DEVICE FOR MEASURING HIGH PRECISION OF THE SPEED OF A MOBILE IN RELATION TO A FLUID THE ENVIRONANT

专利摘要:
Device for very accurate measurement, in real time, of the airspeed VA of a mobile, in particular an aircraft (1), with respect to a mass with a fluid surrounding it, in particular with respect to an ambient air MA surrounding said aircraft (1), and taking into account operational and / or atmospheric conditions, said ambient air mass MA having a direction of movement relative to the aircraft represented by a vector W going from upstream to downstream , said aircraft (1) being able to evolve in a subsonic and / or transonic and / or supersonic speed range, and having at least one fuselage (2), at least one boundary layer CL surrounding said aircraft which has a defined thickness by an angle ALFA, said ALFA angle being defined between the outer surface of the aircraft (1) and a surface where the flow is close to the flow relative to the upstream infinity, said aircraft (1) comprising a structure weakly elastic able to defeat ormer slightly depending on the aerodynamic and / or mechanical and / or thermal stresses experienced by said aircraft, said aircraft (1) being capable of generating a noise B during its displacement and / or its operation in the ambient air mass MA said aircraft (1) having a longitudinal axis OX, a lateral axis OY, a vertical axis OZ constituting an orthonormal coordinate system OXYZ, and comprising at least two acoustic wave generators GA1 and GA2 fixed on the structure of said aircraft (1) respectively at a position G1 and G2 in the OXYZ frame and at least two acoustic wave receivers RAI and RA2 fixed on the structure of said aircraft (1) respectively at a position R1 and R2 in the OXYZ frame, the said receivers RAI and RA2 being furthermore located respectively downstream of the generators GA1 and GA2.
公开号:FR3027398A1
申请号:FR1402359
申请日:2014-10-21
公开日:2016-04-22
发明作者:Robert Schegerin；Bellec Gwezheneg Le
申请人:AER SAS；
IPC主号:

专利说明:

[0001] The present invention relates to a device for measuring, in real time, the accuracy of the speed, in particular anemometric speed, of a mobile, in particular a device for measuring the accuracy of the speed of a moving device relative to a fluid. of an aircraft, with respect to a fluid, in particular to a mass of air, surrounding it independently of the operating conditions and / or the atmospheric conditions, in particular independently of the aerodynamic and / or mechanical and / or thermal stresses experienced by the aircraft; aircraft in the air mass. It particularly relates to an acoustic velocimeter to improve the accuracy and reliability of measuring the relative speed of a mobile relative to a surrounding fluid. It relates more particularly to an acoustic velocimeter for measuring the airspeed of an aircraft relative to the air mass surrounding it. The invention lies in the field of speed sensors of a mobile, in particular a submersible vehicle or terrestrial or aerial, operating under severe operational and / or atmospheric conditions. It is located mainly in the field of anemometric speed sensor of an aircraft operating in severe weather conditions. The invention relates more particularly, but not exclusively, to the reliable measurement of the airspeed of a mobile relative to a surrounding ambient air mass, especially in severe weather conditions (eg snow, heavy rain , lightning, hail, aerodynamic constraints, etc.). There are several devices for measuring the speed of an aircraft with respect to an ambient air mass surrounding said aircraft, in real time. Unfortunately, these devices are sensitive to exceptionally severe operational and / or atmospheric conditions.
[0002] For good airworthiness of the aircraft, particularly its safety and reliability, the speed appears as a fundamental aerodynamic parameter allowing the aircraft to evolve stably in the atmosphere. Indeed, given the low density of air at altitude, the aircraft stalls at a relatively high speed while overspeeding leads to the destruction of the aircraft. Thus, a false speed indication can lead to serious accidents, particularly in the case of simultaneous false information of several speed sensors. As a result, several accidents or serious incidents are certainly due to the incorrect indication of the speed values.
[0003] The pitot probe is one of the means currently used to accurately determine the speed of an aircraft relative to the air mass surrounding said aircraft. This probe is simple and precise, but is very sensitive to very severe atmospheric conditions, especially to strong icing conditions and heavy rains.
[0004] It is known from the state of the art of the airspeed measurement systems using an emitter of electromagnetic waves such as the laser and a receiver associated with said transmitter. Unfortunately, at altitude, the atmosphere is often complex and the use of such waves can cause interference with the transmission frequencies of the control towers communicating with the aircraft. This velocimetry system is therefore not suitable for measuring the airspeed of an aircraft during a flight. It is also known from the state of the art Doppler-based systems. These systems make it possible to measure the speed of the aircraft relative to a fixed point in space and not in relation to the air. Unfortunately, these systems are very sensitive to the aerodynamic and / or mechanical and / or thermal stresses experienced by the aircraft and are therefore not suitable for measuring the airspeed of an aircraft during a flight. From the state of the art is known systems for measuring the airspeed of a mobile relative to a surrounding air mass based on the measurement of propagation time, back and forth of an acoustic wave, usually ultrasound, propagating between two points placed in the ambient air. Unfortunately, this system can not be used to determine the airspeed of an aircraft relative to an air mass surrounding it while being insensitive to severe atmospheric conditions and different aerodynamic and / or mechanical and / or thermal constraints suffered by the aircraft. Indeed, the return or the going is done against the direction of the velocity vector of the ambient air, and if the velocity is close to the velocity of the sound, the traveling distance of the acoustic wave of the return or the to go is very important. In addition, the decrease in the power of the signal being substantially exponential with the distance, the wave eventually fade or disappear before reaching the receiver. This system is inapplicable for measuring the airspeed of the aircraft in all areas of aircraft flight: subsonic and / or transonic and / or supersonic. US Pat. No. 3,222,926 discloses an ultrasound system using at least two receivers and at least one acoustic transmitter making it possible to measure the speed of a mobile with respect to an ambient air mass and possibly the yaw angle and the angle of attack, regardless of atmospheric conditions. Unfortunately, this system is too cumbersome and is not precise, because the acoustic sensors are placed in areas where the boundary layer and / or aerodynamic disturbances are important, especially at the propellers and / or engines and / or wings, but especially at the leading edge. Moreover, in this system, the air is considered homogeneous and the distances separating the sensors are fixed and constant. In addition, the slight deformations of the aircraft are not taken into account, which induces an inaccuracy on the measurement of the airspeed. This system is therefore not suitable for measuring the airspeed of an aircraft relative to the surrounding air mass while being insensitive to the atmospheric conditions and to the various aerodynamic and / or mechanical and / or thermal stresses experienced by the aircraft. the aircraft in all areas of flight of a commercial or military aircraft or a drone. From the publication FR 2 948 458 is known a system for measuring the speed of an aircraft irrespective of meteorological conditions (for example ice, heavy rain, etc.) said system comprising, integral with the airplane, two transmitting couples- ultrasonic receivers (E1, R2), (E2, R1), each transmitter being capable of emitting an acoustic signal and each receiver being capable of receiving an acoustic signal respectively, said couples being located at a fixed distance L one of the 'other. Said system further comprises at least one calculating means for calculating the speed of the aircraft relative to the surrounding air mass when the transmitter El is in front of the aircraft and the receiver R2 is located at the rear of the aircraft and when the emitter E2 is at the rear of the aircraft and the receiver R1 is at the front of the aircraft. Unfortunately, this system makes a round trip whose return is against the direction of displacement of the air mass surrounding the aircraft, especially against the wind, which leads to the total loss of the signal. This system does not make it possible to measure the airspeed of the aircraft relative to the air mass while taking into account the severe atmospheric conditions and the various aerodynamic and / or mechanical and / or thermal stresses experienced by the aircraft in all areas of flight of a commercial or military aircraft or a drone. From the publication WO 2012 150385 is known a precise and reliable device for determining the airspeed of an aircraft independently of atmospheric conditions, said device comprising at least two acoustic generators G1 and G2, capable of emitting respectively at least one train of acoustic wave, respectively fixed on the surface of the aircraft at point CG1 and CG2 respectively, and two acoustic receivers C1 and C2, respectively fixed on the surface of the aircraft at point CC1 and CC2 at the rear of the acoustic generators by relative to the direction of displacement of the air mass surrounding the aircraft and capable of receiving respectively a wave train emitted by the generators G1 and G2 respectively. Unfortunately, in this system, the distances separating the sensors are fixed and constant and the slight deformations of the aircraft are not taken into account, which induces an inaccuracy on the measurement of the airspeed. In addition, the positioning of the sensors, which is an important parameter in the measurement and accuracy of the value of the speed, is not geometrically framed to meet the criteria of precision imposed by the navigation needs. This system therefore does not accurately measure the airspeed of the aircraft relative to a surrounding air mass. One of the main technical problems of the aforementioned velocimetry systems is that, in a severe environment, especially the severe operating and / or atmospheric conditions, the speed measurements are very inaccurate because the structure of the mobile is weakly elastic. and is capable of deforming slightly depending on the operational and / or atmospheric conditions, for example the aerodynamic and / or mechanical and / or thermal stresses experienced by the aircraft on the one hand, and on the other hand, the displacement and / or or the operation of the aircraft in the air mass generates a noise disturbing the speed measurements 10 and making it difficult to continuously evaluate the accuracy of measuring the speed at each instant. In the latter case, aerodynamic noise sources in an aircraft are multiple. The noises result on the one hand from the interactions of the aircraft with the flow. On the other hand, the pressure fluctuations in the turbulent boundary layer around the aircraft excite surfaces, such as the fuselage. Aerodynamic noises are wideband noises in view of the diversity of turbulent structures present in the flow; its active control seems necessary for a good precision on the measurement of the airspeed of an aircraft. For example, the noise of turbojet engines is due to the turbulence of the exhaust jet and combustion, but also to fan noises that emit a characteristic whistling sound, particularly audible on approach and on the ground. Another main technical problem of the aforementioned velocimetry systems is that the geometrical positioning of the generators and the receivers is not governed by physical criteria taking into account the operational and / or atmospheric conditions, in particular on the one hand, of the quality of the signal and the precision of the measurements, since there is a risk of equivalence of the mathematical equations, and secondly, of the nature of the flow (uniform or non-uniform) to take into account the various phenomena aerodynamic. Another main technical problem of the aforementioned velocimetry systems is that the different deformations of the aircraft, in particular the phenomena of aeroelasticities, particularly of the fuselage and the possible effects of the boundary layer, are not taken into account in the calculation of the speed. Indeed, in general, the fuselage, whose section has a shape adapted to reduce the screen, is a structural envelope arranged to transport the payload of the aircraft and to support the other subsets of the aircraft. The fuselage is generally circular for pressurized aircraft. At the beginning of the 20th century, all types of aircraft combined, the use of aluminum-based alloys for the manufacture of the fuselage remains the most common, but composite materials make a notable breakthrough for aircraft carrying 35 passengers . Despite the technical advances in the use of suitable materials for the manufacture of aircraft, the materials constituting the fuselage, but also the wings and empennage, all types of aircraft combined, have a weakly elastic structure and able to deform slightly depending on the operational and / or atmospheric conditions as an example the aerodynamic and / or mechanical and / or thermal stresses to which the aircraft is subjected. This deformation can lead to an increase in the structure of the aircraft and therefore a variation in the distance separating the generator and the acoustic receiver and / or a variation in the path of the acoustic wave trains. In the documents of the state of the art, this deformation is not taken into account to accurately calculate the airspeed of the aircraft. It is therefore clear that under severe operational and / or atmospheric conditions, the structure of the aircraft which is weakly elastic is able to deform slightly. Examples of severe atmospheres are temperature variations. Indeed, the civil or military planes evolve main in the troposphere and / or the stratosphere. In these layers of the earth's atmosphere, the value of the temperature decreases drastically as a function of altitude. Insofar as the expansion of a material is a function of the temperature, it follows a dimensional variation of the structure slightly modifying the dimensions of the aircraft by a few centimeters, lengthening or decreasing the distance between the acoustic generator and the acoustic receiver or lengthening or decreasing the path of the acoustic wave. None of the documents of the state of the art refers to aeroelastic phenomena related in particular to the variation of the temperature to calculate the airspeed of an aircraft. Therefore, it seems necessary to consider other alternatives to the velocimetry systems described in the state of the art, taking into account the severe atmospheric conditions and the various aerodynamic and / or mechanical and / or thermal stresses experienced by the aircraft. aircraft, making it possible to measure and / or improve the accuracy and reliability of the measurements of the speed of the aircraft with respect to a surrounding air mass while resisting said stresses, in all flight areas, especially subsonic and / or transonic and / or supersonic.
[0005] The present invention therefore aims to provide a device for very accurate measurement, in real time, of the airspeed of an aircraft with respect to an ambient air mass surrounding the environmental problems and / or technical problems mentioned above, in particular by improving the accuracy on the measurement of said speed taking into account the different deformations experienced by the aircraft, the noise generated by the aircraft during its displacement in the air mass and the nature of the flow around the aircraft. In the following description, the terms listed below will have the following definition: - Airspeed: speed of the aircraft relative to the surrounding air. - Atmospheric condition: it is the situation of the atmosphere in a given place, on a certain date.
[0006] Severe atmospheric conditions: situation involving very low or very high temperatures and / or including a large quantity of water possibly supercooled and / or a large quantity of crystals and / or aerosols. Operational conditions: any condition encountered in normal flight of an aircraft. - Severe operating conditions: extreme situation of the flight area. - Kilohertz (kHz), Gigahertz (GHz): these are multiples of hertz. Hertz is the unit of measure of frequency. lkHz = 1000 Hz and 1GHz = 1000 kHz. - High precision: ability to distinguish very close values and / or measurements with a greater number of significant digits of the order of a thousandth. - Real time: time shorter than one-tenth of a second. - Subsonic: when the Mach number is less than the critical Mach which corresponds to the appearance of a shock wave. - Transonic: when the local speed becomes equal to the speed of sound; the corresponding Mach Mach number, less than 1, is called the critical Mach. - Supersonic: when the airplane speed is greater than the speed of sound - Limit layer: interface zone between a body and the surrounding fluid during a relative movement between the two, depending mainly on the viscosity of the fluid and its relative speed . - Aerodynamic constraints or aerodynamic loads: it is the force tensor applied by the air on the plane. - Mechanical stresses: these are the existing stresses inside the materials due to forces applied to the structure. - Thermal stresses: these are the existing stresses inside the materials due to temperature variations.
[0007] An active and automatic means: automatic means able to control an action in real time. - Ambient noise: all kinds of ambient noise around the aircraft except the noise emitted by the acoustic wave generator. Upstream: part seeing the airstream first Bottom: part seeing the air flow last - Infinity upstream: place very far ahead of the aircraft, where the relative flow is not modified by the presence of the aircraft. MEMS: Micro-Electro-Mechanical Systems, or microelectromechanical system or electromechanical microsystem, is a microsystem comprising one or more mechanical elements, using electricity as a source of energy, in order to perform a sensor and / or actuator function, with at least one structure having micrometric dimensions, the function of the system being partly ensured by the shape of this structure. CMUT (capacitive MUT): These are transducers that use electrostatic force in parallel-face devices. These transducers require a DC bias voltage and are highly nonlinear. PMUT (piezoelectric MUT): These are transducers that use small piezo elements and most often work in bending mode. The subject of the invention is a device for measuring the real-time accuracy of the airspeed VA of an aircraft with respect to an ambient air mass AM surrounding said aircraft and taking account of operational and / or atmospheric conditions. . Said ambient air mass MA has a direction of movement relative to the aircraft represented by a vector W going from upstream to downstream. Said aircraft is capable of evolving in a subsonic and / or transonic and / or supersonic velocity range, and has at least one fuselage, at least one surrounding CL boundary layer, which has a thickness defined by an ALFA angle. Said angle ALFA is defined between the outer surface of the aircraft and a surface where the flow is close to the flow relative to the upstream infinity. The aircraft according to the invention comprises a weakly elastic structure capable of deforming slightly depending on the operational and / or atmospheric conditions, for example as a function of the aerodynamic and / or mechanical and / or thermal stresses to which said aircraft is subject, and is capable of to generate a noise B during its displacement and / or its operation in the ambient air mass MA. Said aircraft has a longitudinal axis OX, a lateral axis OY, a vertical axis OZ constituting an orthonormal coordinate system OXYZ, and comprises: at least two acoustic wave generators GA1 and GA2 each capable of emitting at least one train of acoustic waves, said generators GA1 and GA2 being fixed on the structure of said aircraft respectively at a position G1 and G2 in the OXYZ coordinate system, and - at least two acoustic wave receivers RAI and RA2 each capable of receiving at least one train of wave emitted by acoustic wave generators GA1 and / or GA2, said receivers RA1 and RA2 being fixed on the structure of said aircraft respectively at a position R1 and R2 in the OXYZ mark. The receiver RA1 is located at a distance D1 of the generator GA1 on the axis OX and at a distance H1 of the generator GA1 on the axis OZ, and the receiver RA2 is located at a distance D2 of the generator GA2 on the axis OX and at a distance H2 from the generator GA2 on the axis OZ, the said receivers RA1 and RA2 are further situated respectively downstream of the generators GA1 and GA2. The device according to the invention is characterized in that the acoustic wave generators GA1 and GA2 and the acoustic wave receivers RA1 and RA2 are fixed on the structure of the aircraft by following the slight deformations of said structure of said aircraft (1), and characterized by the presence of at least two geometric positioning factors FP1 and FP2 defining the positioning domain in the OXYZ frame between the generators GA1 and GA2 and the receivers RA1 and RA2, such that FP1 = D1 / H1 and FP2 = D2 / H2, and characterized in that said positioning domain is chosen such that the geometric positioning factor FP1 is always greater than the geometric positioning factor FP2, and furthermore said geometric positioning factor FP2 is between a minimum value FPMIN and a predefined maximum value FPMAX, and characterized in that, said wave trains emitted by the acoustic wave generators and GA1 and / or GA2 travel from upstream to downstream following the vector W and have an acoustic frequency of between 10 kHz and 100 kHz, and characterized in that each wave train transmitted by the generator GA1 and / or GA2 to the receiver RA1 and / or RA2 is furthermore, with the axis OX, at least one TETA angle greater than or equal to ALFA and said wave trains additionally make at least one BETA angle less than 90 degrees, but different from zero, in a plane of the OXYZ mark, and characterized in that the angle difference TETA-ALFA is between 0.02 degrees and a value TETAmax depending on the geometric characteristics of the aircraft.
[0008] Advantageously, the minimum value of the geometrical positioning factor FPMIN is such that FPMIN = 0.6 and the minimum value of the geometrical positioning factor FPMAX is such that FPMAX = 8 and the value TETAmax is substantially equal to 75 degrees so that, in the XOZ plane, the absolute value of the TETA - BETA difference is less than 90 degrees, preferably less than 75 degrees.
[0009] According to other features of the invention, the measuring device according to the invention further comprises at least one means MC for measuring and calculating, in real time, active and automatic, the airspeed VA with absolute precision PAVA or a relative accuracy PRVA expressed in percent such that PRVA --- 100xPAVA / VA, said means MC comprising simultaneously: - at least one means MC1 for measuring and / or calculating the time Ti of travel of the wave train between the generator GA1 and receiver RA1 and time T2 of course of the train of waves between the generator GA2 and the receiver RA2, following the slight deformations of the structure of the aircraft and - at least one means MC2 measuring and / or calculating the positions G1, G2, R1, R2 and / or distances G1R1 and G2R2 respectively corresponding to the distance between the generator G1 and the receiver R1 and at the distance between the generator G2 and the receiver G2, following the slight deformations from the st the structure of the aircraft, and at least one means for measuring and / or calculating MC3 of the airspeed VA and the speed of sound VS as a function of Ti, T2, G1, G2, R1, R2 and / or function of Ti, T2, G1R1, G2R2, following the slight deformations of the structure of the aircraft.
[0010] And said device further comprises at least one means ME measuring and / or calculating, active and automatic, correction of the value of the airspeed VA and possibly the value of the speed of sound VS improving the absolute accuracy PAVA and / or the relative precision PRVA expressed in percent such that PRVA = 100xPAVA / VA, depending on the operating conditions such as the noise and / or aerodynamic and / or mechanical and / or thermal stresses to which said aircraft is subjected, the value of PRVA preferably being less than 1%; and the means MC and ME are furthermore correlated so that for each value of Ti, T2, G1, G2, R1, R2 and / or of Ti, T2, G1R1, G2R2 measured corresponds one and one only VA value, a PAVA value and / or a PRVA value.
[0011] According to various features of the invention, the measuring device according to the invention furthermore comprises at least one electromagnetic wave generator GE capable of emitting at least one electromagnetic wave train, said wave train having a suitable frequency the aerial regulation and the required performances, said frequency preferably being between 1 and 20 GHz, and at least one electromagnetic wave receiver RE capable of receiving said electromagnetic wave train emitted by said generator GE, said generator GE and receiver RE being fixed on the structure of said aircraft at a position E1 and E2 respectively, following the slight deformations of the structure of said aircraft, said receiver RE being located at a distance GERE of the generator GE so as to measure the relative deformation of the structure said aircraft by measuring in real time the travel time of the electromagnetic wave, and this regardless of the airplane speed. Advantageously, the ME means comprises at least one means ME1 for measuring and / or calculating and regulating the power PA1 and PA2 of the wave trains emitted respectively by said acoustic generators GA1 and GA2, said ME1 means also measuring the power PB of the noise B generated in the operational conditions and / or by the aerodynamic and / or mechanical and / or thermal stresses experienced by the aircraft in the ambient air mass MA, said ME1 means further enabling active control of the power PA1 and / or PA2 as a function of the power PB of the noise B so that the ratio PA1 / PB and / or PA2 / PB is always greater than a predetermined value Pd depending on the operating conditions and / or by the aerodynamic constraints and and / or mechanical and / or thermal, preferably greater than 0.7 or 1.2.
[0012] Advantageously, when the acoustic PB power of the noise B is less than a predetermined value PBm (PB <13 Bm) depending on the operating conditions and / or by the aerodynamic and / or mechanical and / or thermal constraints, for example 60 decibels, for example when the aircraft is stationary, then the power emitted by the generator GAI and / or the generator GA2 is less than or equal to a predetermined value PGm for example 110 decibels, and when the power PB of the noise B is greater than the predetermined value PBm (PB> PBm) the acoustic power emitted by the generator GA1 and / or the generator GA2 is equal to a value greater than said predetermined value PGm, for example 160 decibels. Advantageously, the power PB of the noise B is measured at a place where the power received from the acoustic waves emitted by the generator GA1 and / or GA2 is low and / or the power of the noise B is measured at a time when the power of the waves emitted by the generator GA1 and / or GA2 is weak or zero. According to other features of the invention, the means ME further comprises at least one means ME2 for measuring and calculating the frequency FA1 and FA2 and / or the impedance IA1 and IA2 of the acoustic wave trains transmitted respectively by the acoustic generators GA1 and GA2 and the frequency FB and / or the impedance IB of the noise B generated in the operating conditions and / or by the aerodynamic and / or mechanical stresses experienced by the aircraft in the mass of ambient air MA, said means ME2 further enabling active control of the frequency FA1 and / or FA2 as a function of the frequency FB of the noise B so that the ratio FA1 / FB and / or FA2 / FB is always greater than a predetermined value Fd, and / or said means further enabling control of the impedance IA1 and / or IA2 as a function of the impedance IB of the noise B so that the ratio IA1 / 113 and / or 1A2 / 1B is always greater than a predetermined value Id. According to other characteristics In addition, the ME means comprises at least ME3 means for measuring and calculating the algebraic deviations of the positions PAG1 and PAG2 of the generators GA1 and GA2 respectively and / or the algebraic deviation of the PARI and PAR2 of the receivers RA1 and RA2 respectively and / or algebraic deviations PAG1R1 and PAG2R2 distances G1R1 and G2R2 respectively, depending on the operating conditions and / or depending on aerodynamic and / or mechanical stresses experienced by said aircraft. Advantageously, the ME3 measurement and calculation means also calculates, from the speed VS of the sound, using the tabulated correspondence laws connecting the speed of sound and the ambient temperature, a temperature TA of the ambient air mass. , then using the laws of expansion of the materials and the geometry of the aircraft, the ME3 means calculates the differences PAG1R1 of the distance G1R1 and PAG2R2 of the distance G2R2 as a function of the operating conditions and / or as a function of the aerodynamic constraints and or mechanical undergone by said aircraft. Advantageously, the ME3 measurement and calculation means also calculates, from the airspeed VA and / or the atmospheric pressure, an algebraic deviation PAP to take account of the elongation of the aircraft as a function of the forces of the aircraft. screen applied to the rear parts of the aircraft in order to deduce the algebraic deviations PAG1R1 of the distance G1R1 and PAG2R2 from the distance G2R2 as a function of the operating conditions and / or as a function of the aerodynamic and / or mechanical stresses to which said aircraft is subjected.
[0013] According to other characteristics of the invention, the measuring device according to the invention further comprises a means ME4 for measuring and calculating the electromagnetic wave travel time TEM between the generator GE and the receiver RE and the distance Manages between the generator GE and the receiver RE following the slight deformations of the structure of the aircraft so as to obtain the algebraic deviation PAGERE of the distance GERE and to deduce the algebraic deviation PAG1R1 from the distance G1R1 and the algebraic deviation PAG2R2 of the distance G2R2 as a function of the operational conditions and / or as a function of the aerodynamic and / or mechanical stresses to which said aircraft is subjected. Advantageously, all the means constituting the means MC are correlated with each other and / or all the means constituting the means ME are interrelated with each other. Advantageously, the receivers RA1 and RA2 and / or the generators GA1 and GA2 have an area of at least 16 square millimeters so that, structural deformations undergone by the aircraft, under the operating conditions and / or under the effects aerodynamic and / or mechanical stresses are negligible and do not prevent the receivers RA1 and RA2 from receiving the wave trains emitted by the generator GAI and / or GA2. According to other features of the invention, at least one of the acoustic generators and / or at least one of the acoustic receivers is placed at a point where the deformation effects experienced by the aircraft are substantially negligible so as to measure and calculate with Precise the distances separating the other acoustic generators to the other acoustic receivers, and / or accurately measure the positions of the other acoustic generators and / or other acoustic receivers. Advantageously, the acoustic generators and / or the acoustic receivers are MEMS transducers or magnetostrictive transducers, emitting in the one-third octave band centered on 25 kHz serving for determining the frequencies of each generator. According to other characteristics of the invention, at least one of the acoustic generators and / or receivers is fixed at a place where the thickness of the boundary layer is relatively low and / or where the effects of the boundary layer are relatively small, so that the travel time of the wave train emitted by said generator and / or received by said receiver in the boundary layer is very small, in particular less than a predetermined value TPmax, preferably TPmax = 0.02 seconds.
[0014] According to other characteristics of the invention, the measuring device according to the invention comprises at least two electromagnetic wave generators GE1 and GE2 fixed on the structure of said aircraft at a position Ell and E12 close to the generators GA1 and GA2 respectively, in particular El 1 coincide with G1 and / or E12 coincide with G2, and / or at least two electromagnetic wave receivers RE1 and RE2 attached to the structure of said aircraft at a position E21 and E22 close to the receivers RA1 and RA2 respectively, in particular E21 coincide with R1 and / or E22 coincide with R2. Advantageously, the positions of at least two generators are coincident G1 = G2 or the positions of at least two receivers are merged R1 = R2.
[0015] According to other characteristics of the invention, the measuring device according to the invention comprises an acoustic generator GA12 comprising at least two acoustic generators GA1, GA2 and / or an acoustic receiver RA12 comprising at least two acoustic receivers RA1, RA2. Advantageously, the positions Glet G2 are chosen substantially in the plane of plane symmetry, in an upper part of the fuselage and / or the positions R1 and R2 are chosen substantially in the airplane plane of symmetry, downstream of the positions GA1 and GA2, in the upper part of the vertical empennage. Advantageously, the measuring device according to the invention comprises at least three acoustic wave generators and / or at least three acoustic wave receivers and possibly a means for measuring and calculating the airspeed incidence from the travel times. acoustic waves in order to obtain an accurate value of the incidence and a better accuracy on the value of the high incidence VA speed. The invention also relates to a method of operation of the measuring device according to the invention in which: at least two wave trains are emitted respectively by the acoustic generator GA1 and GA2 respectively towards the receivers RA1 and RA2, the receiver RA1 receives at least one wave emitted by GA1 and the receiver RA2 receives at least one wave emitted by GA2, from the means MC, the travel times of the wave trains Ti and T2 are measured and it is calculated and / or measured, from positions Gl1, G2, R1, R2, distances G1R1 and G2R2, the value of the airplane speed VA and the speed of the sound VS are calculated as a function of Ti, T2, G1, G2, R1, R2 and / or function of Ti, T2, G1R1, G2R2; Advantageously, the operating method of the measuring device according to the invention successively comprises the following steps in which: the value of the power PA1 and / or PA2 of the wave trains emitted by the acoustic generators and the power PB of the noise B are measured. ambient and the ratio PA1 / PB and / or PA2 / PB is calculated, it is verified: o if the ratio PA1 / PB and / or PA2 / PB is greater than the predetermined value Pd as a function of the operating conditions and / or as a function of aerodynamic and / or mechanical stresses experienced by said aircraft in the air mass MA, the value of the power PAlet / or PA2 is kept constant, o if the ratio PA1 / PB and / or PA2 / PB is less than or equal to value Pd, the value of the power PA1 and / or PA2 is substantially increased so as to obtain a ratio PA1 / PB and / or PA2 / PB greater than Pd, the value of the airspeed VA and the speed of sound are corrected. VS as a function of Ti, T2, G1, G2, R1, R2 and / or as a function of Ti, T2, G1R1, G2R2 for the power value PA1 and / or PA2, the absolute accuracy PAVA and / or the relative precision PRVA expressed in percent such as PRVA = 100xPAVA / VA, are calculated as a function of operating conditions and / or depending on the aerodynamic and / or mechanical stresses experienced by said aircraft for the power value PA1 and / or PA2.
[0016] Advantageously, the operating method of the measuring device according to the invention successively comprises the following steps in which: the frequency FA1 and / or FA2 of the acoustic wave trains emitted by the acoustic generators and the frequency FB of the noise B are measured. ambient, and the ratio of the frequencies FA1 / FB and / or FA2 / FB is calculated, - one verifies: o if the ratio FA1 / FB and / or FA2 / FB is higher Fd, then one keeps constant the values of FA1 and / or of FA2, o if the ratio FA1 / FB and / or FA2 / FB is less than or equal to Fd, the value of the frequency FA1 and / or FA2 is substantially increased so as to obtain a ratio FA1 / FB and / or FA2 / FB greater than Fd, - the new value of the airplane speed VA and the speed of sound VS is calculated as a function of Ti, T2, G1, G2, R1, R2 and / or as a function of Ti, T2, G1R1 , G2R2 for the value of the frequency FA1 and / or FA2; the absolute accuracy PAVA and / or the relative precision PRVA expressed in percent, such as PRVA = 100xPAVA / VA, are calculated as a function of the operational conditions and / or as a function of the aerodynamic and / or mechanical stresses experienced by said aircraft for the value of frequency FA1 and / or FA2. Advantageously, the operating method of the measuring device according to the invention successively comprises the following steps in which: the impedance IA1 and / or IA2 of the acoustic wave trains emitted by the acoustic generators and the impedance IB of the noise are measured. B ambient, and one computes the ratio of the impedances IA1 / IB and / or 1A2413, one checks: o if the ratio IA1 / IB and / or 1A2 / B3 is superior to Id, then one keeps constant the values of IA1 and / or of IA2, o if the ratio IA1413 and / or 1A2 / B3 is less than or equal to Id, the value of the frequency IA1 and / or of IA2 is substantially increased so as to obtain a ratio IA1 / IB and / or IA2 / IB greater than Id respectively, - the new value of the airplane speed VA and the speed of sound VS is calculated as a function of Ti, T2, G1, G2, R1, R2 and / or as a function of Ti, T2, G1R1, G2R2 for the value of the frequency IA1 and / or IA2, the absolute accuracy PAVA and / or the relative accuracy PRVA exp is calculated in percent as PRVA = 100xPAVA / VA, depending on the operational conditions and / or the aerodynamic and / or mechanical stresses experienced by said aircraft for the value of the frequency IA1 and / or IA2. Advantageously, the operating method of the measuring device according to the invention successively comprises the following steps in which: the positions G1 and G2 of the generators GA1 and GA2 and / or the new positions R1 and R2 of the receivers RA1 and RA2 are measured and or the new distance G1R1 and G2R2, depending on the operational conditions and / or depending on the aerodynamic and / or mechanical stresses experienced by said aircraft, the algebraic deviations PAG1 and PAG2 of the positions of the generators GA1 and GA2 respectively are calculated and / or the PARI and PAR2 algebraic deviations of the positions of the RAI receivers. and RA2 and / or the algebraic deviations PAG1R1 and PAG2R2 of the distances G1R1 and G2R2 respectively as a function of the operating conditions and / or as a function of the aerodynamic and / or mechanical stresses to which said aircraft is subjected, - the value of the airplane speed VA and the speed of the sound VS as a function of Ti, T2, G1, G2, R1, R2 and / or as a function of Ti, T2, G1R1, G2R2 by integrating the corrections PAG1, PAG2 and / or PAR1, PAR2 of the positions G1, G2, R1, R2 respectively and / or the corrections PAG1R1, PAG2R2, distances G1R1, G2R2 respectively. the absolute accuracy PAVA and / or the relative precision PRVA expressed in percent, such as PRVA = 100xPAVA / VA, are calculated as a function of the operational conditions and / or as a function of the aerodynamic and / or mechanical stresses experienced by said aircraft (1 ) for the values of PAG1, PAG2 and / or PARI, PAR2 and / or PAG1R1, PAG2R2.
[0017] Advantageously, the operating method of the measuring device according to the invention successively comprises the following steps in which: for an operational condition and / or aerodynamic and / or mechanical stresses experienced by said aircraft noted C01, the travel time TEM is measured. of the electromagnetic wave between the generator GE and the receiver RE and the distance GERE is calculated, - for an operational condition and / or aerodynamic and / or mechanical stresses experienced by said aircraft denoted CO2, a new travel time TEM is measured of the electromagnetic wave between the generator GE and the receiver RE and the new distance NGERE is calculated, - one compares the new distance NGERE with the distance GERE and one deduces the algebraic deviation PAGERE = NGERE - GERE of the distance between GE and RE, the value of the aircraft speed VA and the speed of the sound VS are calculated as a function of Ti, T2, G1, G2, R1, R2 and / or as a function of Ti, T2, G1R1, G2R2 by integrating the PAGERE correction with the values of the distances G1R1, G2R2 for an operational condition and / or aerodynamic and / or mechanical stresses undergone by said aircraft (1) denoted CO2, an algebraic deviation PAG1R1 of the distance is deduced G1R1 and an algebraic deviation PAG2R2 of the distance G2R2, - after several iterations, the precise values of VA, VS are obtained as a function of the operational conditions and / or as a function of the aerodynamic and / or mechanical stresses experienced by said CO2 aircraft for the value PAGERE obtained. Advantageously, the method of operation of the measuring device according to the invention successively comprises the following steps in which: - in addition, from the speed VS of the sound, a temperature TA of the ambient air mass is calculated and a difference PATA of said temperature determined from a correlation between the velocity of the sound and the rules of correspondence between the velocity of the sound and the temperature - the algebraic deviation PAG1R1 of the distance GlRlet is deduced from the algebraic deviation PAG2R2 of the distance G2R2 depending on the operational conditions and / or depending on the aerodynamic and / or mechanical stresses experienced by said aircraft. the value of the airplane speed VA and the speed of the sound VS are calculated as a function of Ti, T2, G1, G2, R1, R2 and / or as a function of Ti, T2, G1R1, G2R2 for the algebraic deviations PAG1R1 of the distance G1R1 and PAG2R2 from the distance G2R2, the absolute accuracy PAVA and / or the relative precision PRVA, expressed in percent such as PRVA = 100xPAVA / VA, are calculated as a function of the operating conditions and / or according to the aerodynamic constraints and or mechanical forces experienced by said aircraft for the values of the algebraic deviation PAG1R1 of the distance G1R1 and the algebraic deviation PAG2R2 of the distance G2R2 obtained. The device according to the invention is mainly mounted on an aircraft, since it makes it possible to measure acoustic wave trains and sensor positions directly from the travel times, the airspeed of the aircraft, which is not that the speed of the aircraft relative to the ambient air surrounding said aircraft The device according to the invention may optionally be mounted on any terrestrial or submersible vehicle. In the case of submersible vehicle, the measured speed is not an airspeed, but a submersible speed which is none other than the speed of the mobile relative to the fluid (water or liquid) surrounding said mobile. Advantageously, the aircraft comprises a means for measuring the total pressure, for example using a Pitot tube, obtained at a location on the aircraft, so as to deduce the static pressure at infinity upstream and / or obtain redundancy on the measurement of the speed VA of the aircraft. Advantageously, one of the acoustic wave generators is placed in the alignment of a Pitot tube, just behind it, so as not to create additional halftone and to emit the acoustic wave outside the boundary layer Advantageously , one of the acoustic wave generators is placed in the alignment of an electromagnetic communication antenna, just behind it so as not to create additional halftone and emit the acoustic wave outside the boundary layer.
[0018] Advantageously, the aircraft comprising at least two devices according to the invention, and comprising at least one means for comparing the values of the aircraft speeds VA respectively measured by each device so as to ensure an increased redundancy of the value of the VA speed to improve the accuracy and safety of flying the aircraft. Other characteristics and advantages of the invention, taken alone or in combination, will appear on reading the detailed description which follows for the understanding of which reference will be made to the appended drawings in which: FIG. 1 is a schematic representation of a view in the plane XOZ of an aircraft incorporating a first embodiment of the device according to the invention. FIG. 2 is a diagrammatic representation of an operating flow diagram of the various measurement and calculation means constituting the device according to the invention. FIG. 3 is a schematic representation of a view in the XOZ plane of an aircraft incorporating a second embodiment of the device according to the invention.
[0019] FIG. 4 is a schematic representation of a view in the XOZ plane of an aircraft incorporating a third embodiment of the device according to the invention. FIG. 5 is a schematic representation of a view in the XOZ plane of an aircraft incorporating a fourth embodiment of the device according to the invention.
[0020] FIG. 6 is a schematic representation of an operating flow chart of a means for measuring and calculating the airspeed of the aircraft composing the device according to the invention. FIG. 7 is a schematic representation of an operating flow diagram representing the different interconnections between the different measurement and calculation means composing the device according to the invention. In Figure 1 is shown a side view in the XOZ plane of a modern large aircraft. This figure represents a first embodiment of the device according to the invention. A first acoustic wave generator GAI is placed near the aircraft plane of symmetry on the upper part and at the front of the aircraft. This generator emits a characteristic wave train above and behind.
[0021] Near the upper leading edge of the fin, in particular at the level of the empennage, is placed an acoustic wave receiver RA1. The wave train moves in the air at the speed of sound VS. A second acoustic wave generator GA2 is placed near the plane of symmetry plane and on the upper and central part of the aircraft. This generator emits a characteristic wave train above and behind. Near the upper leading edge of the fin, in particular at the level of the empennage, is placed an acoustic wave receiver RA2. The position sensors GE1, GE2, RE1, RE2 are respectively placed in the same position as each generator GA1, GA2 and each receiver RA1, RA2 to measure in real time the position of each generator and receiver and / or the distance traveled by the wave trains emitted by the GA1 and GA2 generators to the RA1 and RA2 receivers respectively and finally, to evaluate the aeroelasticity.
[0022] In Figure 3 is shown a side view of a modern large aircraft. This figure represents a second embodiment of the device according to the invention. A first acoustic wave generator GA1 is placed near an aircraft plane of symmetry and on the upper part and at the front of the aircraft. This generator emits a characteristic wave train above and behind. Near the upper leading edge of the drift is placed an acoustic wave receiver RA = RA1 + RA2. Acoustic wave trains move in the air at the speed of sound VS. A second acoustic wave generator GA2 is placed near the plane of symmetry plane and on the upper and central part of the aircraft. This generator emits a characteristic wave train above and behind. The RA sensor is designed to also receive the wave trains generated by the GA1 and GA2 sensors. At least one GE position sensor is placed between the generators GA1 and GA2 and at least one position sensor RE is placed close to the receiver RA to evaluate in real time the precision on the position of each generator and / or receiver, and / or the distance traveled by the wave trains emitted by the generators GAI and GA2 to the receiver RA respectively and in particular the variability of the geometric positions of the sensors (generators and receivers).
[0023] In Figure 4 is shown a side view of a modern large aircraft. This figure represents a third embodiment of the device according to the invention. A GA acoustic wave generator is placed on the upper part of the aircraft and in particular near the plane of symmetry plane and the front of the aircraft. This generator emits a characteristic wave train above and behind. Near the upper leading edge of the fin, in particular at the level of the empennage (3) is placed an acoustic wave receiver RAL Near the upper drift leading edge is placed in addition an acoustic wave receiver RA2 also receiving the wave trains generated by GA. A GE position sensor is placed near the plane of symmetry on the same axis as the generator GA and a position sensor RE is placed near the upper leading edge of the drift close to RA1 and RA2.
[0024] In Figure 5 is shown a side view of a modern large aircraft. This figure represents a fourth embodiment of the device according to the invention. Three acoustic generators GA1, GA2 and GA3 are placed on the top of the fuselage (2) near the airplane plane of symmetry respectively on the front part, on the central part, and on the rear part of the fuselage (2). These generators emit wave trains above and behind. Near the upper leading edge of the fin (3), especially at the level of the empennage (3) is placed an acoustic wave receiver RA12 = RA1 + RA2 + RA3. This acoustic sensor RA12 is designed to receive the three wave trains generated by the generators GA1, GA2 and GA3 respectively. In another embodiment not shown here, a first acoustic generator is placed near the airplane plane of symmetry and on the upper part of the central engine air inlet, this generator emits characteristic wave trains above and back. Near the upper leading edge of the drift is placed an acoustic wave receiver and near the leading edge and halfway up the drift is also placed another acoustic wave receiver also receiving the wave train generated by said generator. Referring to FIG. 1, there is shown a device for very accurate measurement, in real time, of the airspeed VA of an aircraft (1) with respect to an ambient air mass AM surrounding said aircraft, and taking into account operational and / or atmospheric conditions of the environment where the aircraft is located. The ambient air mass MA has a direction of movement relative to the aircraft (1) represented by the vector W going from upstream to downstream, that is to say, in the opposite direction of the displacement of the aircraft. Indeed, the aircraft (1) receives the ambient air MA by its front part and moves in a direction opposite to the vector W. The direction of movement of the aircraft (1) is represented by the vector VA, corresponding to the direction of the airspeed vector of the aircraft (1). The aircraft (1) is capable of operating in a subsonic and / or transonic and / or supersonic speed range. The aircraft (1) mainly comprises a fuselage (2), a wing (4), a stabilizer (3) (horizontal stabilizer and / or drift) and at least one landing gear. The aircraft comprises at least one boundary layer CL surrounding which has a thickness defined by an angle ALFA, said ALFA angle is defined between the outer surface of the aircraft (1) and a surface where the flow is close to the relative flow at the infinite upstream. The aircraft (1) has a longitudinal axis OX, a lateral axis OY, a vertical axis OZ, said axes forming an orthonormal reference OXYZ constituting the aircraft geometrical reference.
[0025] The aircraft (1) comprises a weakly elastic structure capable of deforming slightly in the OXYZ mark, depending on the operational and / or atmospheric conditions, for example as a function of the aerodynamic and / or mechanical and / or thermal stresses experienced by said aircraft . The aircraft generates a noise B during its displacement and / or its operation in the ambient air mass MA. This is the engine noise, the noise of the exhausts, possibly the noise of the bearings, and mainly aerodynamic noise. An active control system is developed and put in place to control said noise B. As shown in FIG. 1, the device according to the invention comprises two acoustic wave generators GA1 and GA2, each capable of emitting at least one acoustic wave train.
[0026] Said generators GA1 and GA2 are fixed on the structure of the aircraft (1) respectively at a position G1 and G2 following the slight deformations of the structure of said aircraft (1) along the directions OX, OY and OZ. Said device also comprises two acoustic wave receivers RA1 and RA2, fixed on the structure of said aircraft (1) respectively at a position R1 and R2, following the slight deformations of the structure of said aircraft (1) along the directions OX, OY and OZ. Said receivers RA1 and RA2 are situated respectively downstream of the generators GA1 and GA2 respectively. The acoustic receiver RA1 is capable of receiving at least one wave train emitted by the acoustic wave generator GA1 and the acoustic receiver RA2 is capable of receiving at least one wave train emitted by the acoustic wave generator GA2. Such an arrangement makes it possible to have two acoustic wave train paths corresponding to two mathematical equations with two unknowns, the unknowns of which are the anemometric speed VA and the speed of the sound VS so as to determine in a single measurement, the airspeed VA and VS sound speed. According to an alternative embodiment, the acoustic receiver RA1 is capable of receiving at least one acoustic wave train emitted by the acoustic wave generators GA1 and GA2 and the acoustic receiver RA2 is capable of receiving at least one transmitted wave train by acoustic wave generators GA1 and GA2. Such an arrangement makes it possible to have four acoustic wave train paths, corresponding to four mathematical equations having four unknowns among which there is the airspeed VA and the speed of sound VS.
[0027] Each wave train emitted by the generators has a path from upstream to downstream in a direction substantially along the vector W to be received by at least one receiver. Indeed, in the direction of the vector W, the acoustic wave is driven by the ambient air mass and easily reaches the receiver placed a few meters. In this way, each wave emitted by at least one generator is able to reach the receiver regardless of the flow, because the velocity vector of the acoustic wave in the same direction as the vector W represents the flow. Each wave train has an acoustic frequency in the ultrasound band, in particular a band between 10 kHz and 100 kHz. This frequency band is chosen to allow easy use in both low flow (homogeneous flow) and high flow (turbulent flow) taking into account the operational and / or atmospheric conditions surrounding the aircraft, including attitude. Moreover, in this frequency band, the emission efficiency of the generators, the variation of the directivity with the frequency, the variation of the absorption, the disturbances of the noise level and the constraints of signal processing in real time are weak. . Moreover, in this band of 10 kHz and 100 kHz, the wavelength, depending on the operational and / or atmospheric conditions, varies very slightly. Generators and receivers are coordinated and / or geometrically framed by a geometric relation called geometric positioning factor which defines the position and / or the geometric location of the sensors (generator and receiver) on the fuselage (2) and / or the empennage (3) of the aircraft (1) and in particular with respect to the boundary layer CL.
[0028] In the embodiment according to FIG. 1, the device according to the invention comprises at least two geometrical positioning factors FP1 and FP2 defining the positioning domain between the generators GA1 and GA2 and the receivers RA1 and RA2, in the reference OXYZ, such as FP1 = D1 / H1 and FP2 = D2 / H2. This positioning domain is chosen so that the geometric positioning factor FP1 is always greater than the geometric positioning factor FP2, and furthermore the geometric positioning factor FP2 is between a minimum value FPMIN and a predefined maximum value FPMAX. Each wave train emitted by the generator GA1 and / or GA2 to the receiver RA1 and / or RA2 each have, with the axis OX, at least one TETA angle greater than or equal to an ALFA and said wave trains making moreover between them at least a BETA angle less than 90 degrees, but different from zero, in the XOY plane and / or XOZ and / or YOZ of the OXYZ mark. In addition, the angle difference TETA-ALFA is between 0.02 degrees and a value TETAmax depending on the geometric characteristics of the aircraft. Advantageously, the minimum value FPMIN and the maximum value FPMAX of the geometrical positioning factor are chosen such that: FPMIN = 0.6 and FPMAX = 8. The maximum value TETAmax is chosen substantially equal to 75 degrees so that in the XOZ plane, the absolute value of the TETA-BETA difference is less than 90 degrees, preferably less than 75 degrees. These different parameters, TETA, ALFA, BETA, FP1, FP2, FPMIN, FPMAX make it possible to ensure that the attenuation and / or absorption effects of the power of the trains are low in the interface zones between the aircraft and the fluid surrounding it during a relative movement between said aircraft and the surrounding fluid. In general, they make it possible to avoid any disturbance of the acoustic wave trains in the boundary layer. As a reminder, the boundary layer represents the region of flow where the viscous effects are at least as important as the inertial effects (in terms of order of magnitude). This is indeed not the case far from the wall, where the flow is then called "Euler", and where the viscous effects are practically not felt. According to other features of the invention, each wave train emitted by a generator GA1 or GA2 to the receiver RA1 and / or RA2 makes with the axis OX a TETA angle greater than or equal to 4 degrees. The wave trains emitted by the generators GA1 and GA2 also have a BETA angle greater than 4 degrees between them.
[0029] The value of the angle TETA is chosen such that the influence of the boundary layer on the propagation of the acoustic wave is substantially negligible and that the small thickness of the boundary layer implies that the derivatives of the speed in the direction propagation of the acoustic wave are much lower, in particular substantially negligible. In the context of the present invention, the boundary layer is due to aerodynamic phenomena, in particular by the nonlinear flow around the aircraft and / or generated by the displacement of the aircraft in the air mass surrounding it. The value of the BETA angle is chosen such that the influence of the boundary layer on the reception of the acoustic wave is substantially negligible and that the wave trains emitted by at least one generator GA1 or GA2 are received either by a receiver, or by both receivers; which allows to determine directly, for a single measurement, the airspeed of the aircraft, the speed of sound in the air mass surrounding the aircraft and possibly, but not necessarily, the angle of incidence and the pitch angle. This value of BETA is also chosen to avoid the effects of the airspeed.
[0030] When the acoustic wave is emitted in the boundary layer, taking into account the severe atmospheric conditions and the various aerodynamic and / or mechanical and / or thermal stresses experienced by the aircraft, it is trapped in the potential well created by the boundary layer. and takes a while to get out of it. Indeed, under the severe atmospheric conditions and taking into account the various aerodynamic and / or mechanical and / or thermal stresses experienced by the aircraft, the influence of the turbulence of the upstream flow and the Reynolds number become very important in the morphology and dynamics of highly anisotropic turbulent flows around the aircraft and therefore the distribution of pressures on the fuselage surface (2) and possibly the empennage (3) and / or the wing (4).
[0031] This has a considerable effect on the boundary layer along the aircraft structure and on the points of stitching. Also, upstream turbulence has an influence on the location of the shear layer bonding point and the consequences can be very important in aeroelasticity. To avoid this constraint which induces a delay or an advance to the acoustic wave and which seems to modify the trajectory of said wave and the precision on the measurement of the speed, the sensors (generators and receivers) are placed in an area where the Thickness of the boundary layer is small by respecting a geometric relation defined by the safety parameters called geometric positioning factor FP. Indeed, the generators and the receivers must be positioned correctly in order to make the system work as well as possible to obtain a better precision on the measurement of the speed.
[0032] In order to increase the accuracy of the device according to the invention, it is necessary to move away from the domains where the equations, making it possible to determine the speed from the travel times, are equivalent to obtain more information and precision on the value. the airspeed. For this purpose, the geometric positioning factor FP2 of the acoustic generator-receiver pair (GA2, RA2) or (GA2, RA1) corresponding to the ratio of the distance D2 to the height H2 (D2 / H2) is chosen strictly less than at least a positioning factor FP1 of the acoustic generator-receiver pair (GA1, RA2) or (GA1, RA1) corresponding to the ratio of the distance D1 to the height H1 (D1 / H1), where D1 is the distance on the OX axis between the generator GA1 and the receiver RA1 or RA2, and D2 the distance on the axis OX between the generator GA2 and the receiver RAlou RA2, H1 is the distance on the axis OZ between the generator GA1 and the receiver RA1 or RA2, and D2 the distance on the OZ axis between the generator GA2 and the receiver RAlou RA2. According to the invention, the airspeed VA and the speed of the sound VS, and possibly the angle of incidence, are determined from the geometrical data and the travel times of the acoustic wave trains. In order to be able to determine the speed precisely, it is preferable for the geometric positioning factor FP2 to be between a predefined minimum value FPMIN, preferably FPMIN = 0.6 and a predefined maximum value FPMAX, preferably FPMAX = 8.
[0033] Advantageously, the geometrical positioning factor FP1 is always greater than the geometrical positioning factor FP2, and furthermore said geometrical positioning factor FP2 is between a minimum value FPM1N and a predefined maximum value FPMAX. Advantageously, the wave trains transmitted by the generator GA1 and / or GA2 to the receiver RA1 and / or RA2 make, with the axis OX, at least one TETA angle greater than or equal to ALFA and said wave trains make in addition to each other at least BETA angle less than 90 degrees, but different from zero, in the plane XOY and / or XOZ and / or YOZ of the OXYZ mark, and that the angle difference TETA-ALFA is between 0.02 degree and a TETAmax value depending on the geometric characteristics of the aircraft aircraft.
[0034] Advantageously, FPMIN = 0.6 and FPMAX = 8 and the value of TETAmax is substantially equal to 75 degrees so that in the XOZ plane, the absolute value of the TETA-BETA difference is less than 90 degrees, preferably less than 75 degrees. With reference to FIG. 2, the device according to the invention comprises at least one means MC and a means ME for measurement and calculation.
[0035] The MC means is a means for measurement and calculation, in real time, active and automatic, of the airspeed VA with absolute accuracy PAVA or a relative precision PRVA expressed in percent such as PRVA-100xPAVA / VA. This means MC comprises at the same time: at least one means MC1 for measuring and calculating the time Ti of travel of the wave train between the generator GA1 and the receiver RA1 and time T2 for traveling the wave train between the generator GA2 and the receiver RA2 following the slight deformations of the structure of the aircraft (1), and o at least one means MC2 for measuring and calculating positions G1, G2, R1, R2 and / or corresponding distances G1R1 and G2R2 respectively at the distance between the generator G1 and the receiver R1 and at the distance between the generator G2 and the receiver R2, following the slight deformations of the structure of the aircraft (1), o at least one means for measuring and MC3 calculation of the VA airspeed and the sound velocity VS as a function of Ti, T2, Gl, G2, R1, R2 and / or as a function of Ti, T2, G1R1, G2R2, following the slight deformations of the structure of the aircraft (1).
[0036] Gl, G2, are respectively geometric positions of the acoustic generators GA1 and GA2, and R1 and R2 are geometric positions of the acoustic receivers RA1, RA2. Said different geometrical positions and the distances Gl R1 and G2R2 can be measured with great accuracy better than one thousandth of a millimeter. Given the aerodynamic and / or mechanical and / or thermal stresses to which the aircraft is subjected, in particular the phenomena of aeroelasticities and disturbances due to the noises generated by the displacement of the aircraft in the air mass, the positions G1, G2, R1, R2 and the distances G1R1, G2R2 are defined to take into account said constraints and said disturbances. This makes it possible to measure and / or calculate the positions G1, G2, R1, R2 and / or the distances G1R1, G2R2 with an accuracy better than one thousandth. The values of Ti and T2 are measured with an accuracy better than one tenth of the microsecond, preferably better than one nanosecond. The values obtained can be verified on the ground, at zero speed, and the system can be recalibrated for example at each startup of the system. There is an unambiguous mathematical relation RM1 of the form VA = RM1 (T1, VS) between the travel time T1 and the speed of the aircraft, for a given speed of its VS. Similarly, there is an unambiguous mathematical relationship RM2 of the form VA = R1V12 (T2, VS) between the travel time T2 and the speed of the aircraft VA, for a given speed of sound. These relations lead to a system of two equations with two unknowns, the unknowns being VA and VS. The mathematical resolution of the said equations gives the value of VS and VA very precisely according to the constraints and disturbances previously mentioned. The ME means is a measurement and calculation means, active and automatic, for correcting the value of the airspeed VA and possibly the value of the sound velocity VS calculated with the MC means to improve the absolute accuracy PAVA and / or the relative precision PRVA expressed in percent such that PRVA = 100xPAVA / VA, depending on the operating conditions such as noise for example and / or depending on aerodynamic and / or mechanical and / or thermal constraints experienced by said aircraft (1 ) as the aeroelasticity, the pressurization of the cabin. The value of PRVA is preferably less than 1%. The two means MC and the means ME are correlated so that, for each value of Ti, T2, G1, G2, R1, R2 and / or of Ti, T2, G1R1, G2R2 measured, can correspond to one and a single VA value, a PAVA value and / or a PRVA value. In this way, for all kinds of constraints mentioned above, the value of the airspeed is always accurate. The ME means comprises a plurality of means, ME1, ME2, ME3 and ME4, capable of checking and correcting, using other measurement and calculation techniques including iterative, the value of the airspeed VA and the accuracy of PAVA and / or PRVA at any time regardless of the constraints and / or severe weather conditions. The ME and MC means comprise active control systems for aerodynamic or ambient noise. This active control system includes a propeller or engine noise control system, a fan noise control system, a turbulent boundary layer noise control system, and a flow noise control system. As shown in Figure 1 and Figure 6, a method of operation of the device according to the invention is shown. According to the invention, at least two wave trains are emitted respectively by the acoustic generator GA1 and GA2 in the direction respectively of the receivers RA1 and RA2, said wave trains being substantially in the same direction as the vector W. The receiver RA1 receives at least one wave transmitted by GA1 and the receiver RA2 receives at least one wave transmitted by GA2. From the means MC, the travel times of the wave trains T1 and T2 are measured and the distances G1R1 and G2R2 are calculated and / or measured from the positions G1, G2, R1, R2. The value of the aircraft speed VA and the speed of the sound VS are then calculated as a function of Ti, T2, G1, G2, R1, R2 and / or as a function of Ti, T2, G1R1, G2R2. With reference to FIG. 1, the device according to the invention further comprises, but not necessarily, two electromagnetic wave generators GE1 and GE2 capable of emitting at least one electromagnetic wave train, said wave train having a frequency adapted to the air regulations and the required performances, said frequency preferably being between 1 and 20 GHz; and two electromagnetic wave receivers RE1 and RE2 capable of receiving said electromagnetic wave train emitted by said generators GE1 and GE2. The generators GE1 and GE2 are fixed on the structure of the aircraft at a position El 1 and El 2 respectively following the slight deformations of the structure of the aircraft (1). The receivers RE1 and RE2 are fixed on the structure of the aircraft at a position E21 and E22 respectively following the slight deformations of the structure of the aircraft (1). In this way, it is possible to measure the relative deformation of the structure of said aircraft (1), in particular aeroelasticity, by measuring in real time the distance traveled by the electromagnetic wave and by comparing said distance with the values of the distances separating the aircraft. generators and receivers at rest.
[0037] With reference to FIG. 3, the aircraft (1) comprises two acoustic generators GA1 and GA2 capable of transmitting at least one acoustic wave train to an RA receiver. In this embodiment, the receivers RA1 and RA2 are merged and grouped into a single receiver RA or the receiver RA is a multi-function receiver. The latter thus constitutes a single and unique receiver capable of receiving the wave train emitted by the two acoustic generators RA1 and RA2. According to other characteristics of the invention, the receivers RA1 and RA2 are not confused or grouped, but placed in a single point R1 = R2 = R. According to other characteristics of the invention, the device further comprises a GE electromagnetic wave generator capable of transmitting an electromagnetic wave train to an electromagnetic wave receiver RE. The acoustic generators GA1 and GA2 are fixed on the aircraft structure at a position G1 and G2 respectively following the slight deformations of the aircraft structure (1). The acoustic receivers RA1 and RA2 are fixed on the structure of the aircraft at a position R1 and R2 respectively: R1 = R2 = R, following the slight deformations of the structure of the aircraft (1). The electromagnetic generator GE and the electromagnetic receiver RE are fixed on the structure of the aircraft at a position E1 and E2 respectively following the slight deformations of the structure of the aircraft (1). With reference to FIG. 4, the device according to the invention comprises an acoustic generator GA grouping the acoustic generators GA1 and GA2 or a multifunction acoustic generator GA, two acoustic receivers RA1 and RA2. It further comprises, but not necessarily, a GE electromagnetic generator and an electromagnetic RE receiver. The acoustic generator GA is capable of emitting at least two acoustic wave trains and the two acoustic receivers RA1 and RA2 are capable of receiving at least one wave train emitted by the acoustic generator GA. The electromagnetic generator GE is capable of emitting at least one electromagnetic wave train and the electromagnetic receiver RE is capable of receiving at least one wave train emitted by the electromagnetic generator GE. According to other characteristics of the invention, the acoustic generator GA comprises two acoustic generators GA1 and GA2. According to other characteristics of the invention, the generators GA1 and GA2 constituting the generator GA are fixed at respective positions G1 and G2, such that G1 = G2.
[0038] With reference to FIG. 5, the device comprises three acoustic generators GA1, GA2, GA3 each capable of transmitting an acoustic wave train and at least one acoustic receiver RA capable of receiving the wave trains emitted by said acoustic generators. The acoustic generators are respectively placed at distinct positions G1, G2 and G3. An alternative is that the acoustic receiver RA comprises a plurality of receivers, in particular RA1, RA2, RA3, fixed at a position R1 = R2 = R3-R. Other embodiments in terms of representation and / or geometric position of the sensors are shown in WO 2012 150385 in which this device is improved. With reference to FIG. 2 and FIG. 6, the means MC comprises a multiplicity of measurement and calculation means, in particular the means MC1, MC2, MC3. Said means MC1, MC2, MC3 interact with each other and with other measuring and / or calculation means, in particular with the ME means. The means MC1 is mainly dedicated to the measurement and calculation of acoustic wave travel times in a severe environment taking into account the effects of the boundary layer and the other constraints defined above. This means is capable of measuring the travel times Ti and T2 with an accuracy of the order of a few nanoseconds, because in some media, the difference in Ti-T2 times may be of the order of one microsecond. For this purpose, increased accuracy is required for accurate measurement of the airspeed.
[0039] The means MC2 is mainly dedicated to the measurement and calculation of the geometric positions of the acoustic generators and receivers, in particular the distances separating each receiver and each acoustic generator. This means is capable of measuring and / or calculating with a precision of the order of a micrometer, in particular of the order of a nanometer in a certain medium, the geometrical positions G1, G2, R1, R2 of the generators and receivers and / or the distances G 1 R1, G2R2 separating each generator and each receiver. Said means MC3 is coupled to other means of measurement and / or calculation, in particular the ME means to take into account the severe environment taking into account the effects of the boundary layer and the other constraints previously defined above, in particular the aeroelasticity phenomenon for example. The means MC3 is dedicated mainly to the measurement and calculation of the airspeed and velocity VS sound velocity and possibly the angle of incidence, pitch, trim, etc., from the train travel times acoustic waves, in particular T1 and T2, and distances separating each generator and each acoustic receiver (G1R1, G2R2) and / or the positions of each generator and receiver (G1, G2, R1, R2). This means is capable of calculating with an accuracy of the order of 0.01%, preferably an accuracy of less than 1%, the airspeed VA and possibly the speed of sound VS. This means MC3 is coupled to other means of measurement and / or calculation, in particular the means ME to take into account the severe environment taking into account the effects of the boundary layer and the other constraints previously defined above, in particular the aeroelasticity phenomenon for example and that for each value of Ti, T2, G1, G2, R1, R2 and / or of Ti, T2, G1R1, G2R2 measured, can correspond to one and only one value of VA, a PAVA value and / or a PRVA value. As represented in FIG. 2, the ME means comprises a multiplicity of measurement and calculation means, in particular the MEI, ME2, ME3 and ME4 means. The ME1 means is a means for measuring, calculating and regulating the power of the acoustic wave trains emitted by each acoustic generator. The generator GA1 emits an acoustic wave with a power PA1 and the acoustic generator GA2 emits an acoustic wave with a power PA2. The ME1 means also measures and / or calculates the power PB of the ambient noise B generated by the aircraft under the operating conditions and / or by the aerodynamic and / or mechanical and / or thermal stresses to which the aircraft (1) the ambient air mass MA, in particular the noise B generated by the displacement of the aircraft in the mass and / or by the engines and / or by the air mass surrounding the aircraft. The ME1 means is furthermore a means for actively controlling the power PA1 and / or PA2 as a function of the power PB of the noise B so that the ratio PA1 / PB and / or PA2 / PB is always greater than a value predetermined Pd depending on the operating conditions and / or aerodynamic and / or mechanical and / or thermal constraints, preferably greater than 0.7 or 1.2. A simple method makes it possible to determine the value of Pd. Pd is of course a dimensionless value depending on the operational conditions of the aircraft as well as aerodynamic and / or mechanical and / or thermal constraints. The value of Pd is determined by an iteration that compares the noise power B surrounding the aircraft with the characteristics of the environment, because the difference between the acoustic wave train emitted by at least one generator and the noise B is enough. wave and this appreciation is different depending on the case. Indeed, an acoustic wave train is defined as noise when it is uncomfortable, annoying. For example on the ground, the environment of the aircraft is human, that is to say people can move freely near the aircraft In such cases, the noise is judged according to the people around the aircraft. Aircraft It should be noted that the frequencies audible by humans (people) range from 20 Hz to 20 kHz. Above 20 kHz, it is ultrasound that does not give rise to a sound sensation except exception. A simpler example of Pd is that, on the ground and at rest, the engines of the aircraft are running, the environment and the engines, together, generate a noise B of about 80 decibels. In such a case, Pd is chosen to be 1.2, ie PA1 and / or PA2 equal to 100 decibels. This value of PA1 and / or PA2 is acceptable because it is not contrary to the hearing limits of the human being.
[0040] Another example is that at take-off from an airplane, the power PB is 130 dB. In this case, Pb is chosen at 1.4 or 2 so as to obtain a good signal-to-noise ratio making it possible to appreciate the value of the aircraft airspeed VA. Another example is that, when the acoustic power of the noise B is less than a predetermined value PBm (PB <PBm) depending on the operating conditions and / or by the aerodynamic and / or mechanical and / or thermal constraints, for example 60 decibels when the aircraft is stationary, then the power emitted by at least one of the generators GA1 and / or GA2 is less than or equal to a predetermined value PGm, for example 110 decibels, and when the power of the noise B is greater than the predetermined value PBm (PB> PBm) the acoustic power emitted by at least one of the generators GA1 and / or GA2 is equal to a value greater than said predetermined value PGm, for example 160 decibels. For a good match of the Pd values and / or a good weighting of the Pd values taking into account the operational conditions and / or aerodynamic constraints previously defined, weighting curves have been established in the literature matching the frequencies. and the powers likely to have an impact on the human ear. These weights make it possible to take into account approximately the variation of the sensitivity of the ear as a function of the frequency and the intensity of the wave trains.
[0041] For a good appreciation of the noise B and for a better precision on the measurement and / or the calculation of the airspeed of the aircraft (1), the power of the noise B is measured at a place where the power of the acoustic waves emitted by the generator GA1 and / or GA2 is weak and / or the power of the noise B is measured at a time when the power of the waves emitted by the generator GA1 and / or GA2 is low. Preferably, the predetermined value Pd is determined by using acoustic signal correlation methods taking into account the flight conditions of the aircraft and the reference electronics relative to the generator and / or receiver. The acoustic signal correlation method comprises comparing a noise signal with a transmission signal of at least one generator and regulating the signal strength according to the sensitivity of the receiver and / or the power received by the acoustic receiver. . According to a method of operation of the device according to the invention, the following steps are successively adopted: the value of the power PA1 and / or PA2 of the wave trains emitted by the acoustic generators and the power PB of the ambient noise B are measured. the ratio PA1 / PB and / or PA2 / PB is calculated: - it is verified: o if the ratio PA1 / PB and / or PA2 / PB is greater than the predetermined value Pd as a function of the operating conditions and / or according to the constraints aerodynamic and / or mechanical undergone by said aircraft (1) in the air mass MA, the value of the power PA1 and / or PA2 is kept constant. For example, when stopped, this value Pd is chosen equal to 1.2. o if the ratio PA1 / PB and / or PA2 / PB is less than or equal to the value Pd, the value of the power PA1 and / or PA2 is substantially increased so as to obtain a ratio PA1 / PB and / or PA2 / PB greater than Pd; the value of the anemometric speed VA and of the speed of the sound VS is corrected as a function of Ti, T2, G1, G2, R1, R2 and / or as a function of Ti, T2, G1R1, G2R2 for the power value PA1 and / or PA2; the absolute accuracy PAVA and / or the relative precision PRVA expressed in percent, such as PRVA-100xPAVANA, are calculated as a function of the operational conditions and / or as a function of the aerodynamic and / or mechanical stresses experienced by said aircraft (1) for the power value PA1 and / or PA2. The means ME2 is a means for measuring and calculating the frequency FA1 of the acoustic wave trains emitted by the generator GAI and the frequency FA2 of the acoustic wave trains emitted by the acoustic generator GA2. It is also a means for measuring and calculating the impedance IA1 of the acoustic wave trains emitted by the generator GA1 and the impedance IA2 of the acoustic wave trains emitted by the acoustic generator GA2. This means ME2 also measures the frequency FB and / or the impedance IB of the noise B generated by the air mass MA and / or the displacement of the aircraft in the air mass MA under the operating conditions and / or noise generated by the aerodynamic and / or mechanical stresses experienced by the aircraft (1) in the ambient air mass MA. The means ME2 is particularly a means for actively controlling the frequency FA1 and / or FA2 as a function of the frequency FB of the noise B so that the ratio FA1 / FB and / or FA2 / FB is always greater than a predetermined value. Fd depending on the operational conditions and / or aerodynamic and / or mechanical and / or thermal constraints. The means ME2 is furthermore a means for controlling the impedance IA1 and / or IA2 as a function of the impedance IB of the noise B so that and / or the ratio IA1 / 1B and / or IA2 / IB is always greater than a predetermined value Id depending on the operating conditions and / or aerodynamic and / or mechanical and / or thermal constraints. A simple method makes it possible to determine the values of Fd and Id. This method is equivalent to that making it possible to determine Pd. For example, when stopped, the aircraft is in an environment where human presence is possible. As a result, the frequency is adapted so as not to destroy the human ear. For example, the noise frequency is 4 kHz in an airport, the value of Fd is chosen to be 1.1. According to an operating method of the device according to the invention, the following steps are successively adopted: the frequency FA1 and / or FA2 of the acoustic wave trains emitted by the acoustic generators and the frequency FB of the surrounding ambient noise B are measured. aircraft, and the frequency ratio FA1 / FB and / or FA2 / FB is calculated. we check: o if the ratio FA1 / FB and / or FA2 / FB is higher Fd, then we keep constant the values of FA1 and / or FA2. o if the ratio FA1 / FB and / or FA2 / FB is less than or equal to Fd, the value of the frequency FA1 and / or FA2 is substantially increased so as to obtain a higher ratio FA1 / FB and / or FA2 / FB at Fd. the new value of the airplane speed VA and of the speed of the sound VS is calculated as a function of T1, T2, G1, G2, R1, R2 and / or as a function of T1, T2, G1R1, G2R2 for the value of the frequency FA1 and / or FA2. the absolute accuracy PAVA and / or the relative precision PRVA expressed in percent, such as PRVA ---- 100xPAVA / VA, are calculated as a function of the operating conditions and / or according to the aerodynamic and / or mechanical stresses experienced by said aircraft (1) for the value of frequency FA1 and / or FA2.
[0042] According to another operating method of the device according to the invention, the following steps are successively adopted: the impedance IA1 and / or IA2 of the acoustic wave trains emitted by the acoustic generators and the impedance IB of the noise B are measured. ambient, and the ratio of the impedances IA1413 and / or 1A2 / 13 is calculated, - one verifies: o if the ratio IA1 / IB and / or IA2 / IB is greater than Id, then one keeps constant the values of IA1 and / or of IA2. o if the ratio IAl / lB and / or IA2 / IB is less than or equal to Id, the value of the frequency LAI and / or IA2 is substantially increased so as to obtain a ratio IAMB and / or IA2 / IB greater than Id respectively; . the new value of the airplane speed VA and of the speed of the sound VS is calculated as a function of Ti, T2, G1, G2, R1, R2 and / or as a function of Ti, T2, G1R1, G2R2 for the value of the frequency IA1 and / or IA2. the absolute accuracy PAVA and / or the relative precision PRVA expressed in percent such as PRVA = - 100xPAVA / VA, are calculated as a function of the operational conditions and / or as a function of the aerodynamic and / or mechanical stresses experienced by said aircraft ( 1) for the value of the frequency IA1 and / or IA2. In a given atmosphere, the knowledge of the thermal structure of the air mass surrounding the aircraft as well as the direction of the wind seems an important parameter for the determination of the speed, because the sound can spread less horizontally only at rising angles because of the change in density. In addition the attenuation is significantly less strong downwind and the wind gradient layer acoustic wave by folding it towards the aircraft, conversely the wave moving against the wind fades quickly. Hence the choice to fix the generators in a suitable position so that each generator emits a wave train from upstream to downstream, that is to say, emits a wave train having the same direction as the vector W representing the ambient air and in that each receiver is placed in a position capable of receiving at least one acoustic wave train emitted by each generator. The ME3 means is a means for measuring and calculating the algebraic deviations PAG1 and PAG2 of the positions of the generators GA1 and GA2 respectively and / or the algebraic deviations PARI and PAR2 of the positions of the receivers RA1 and RA2 and / or the algebraic deviations PAG1R1 and PAG2R2 distances G1R1 and G2R2 respectively according to the operating conditions and / or depending on the aerodynamic and / or mechanical stresses experienced by said aircraft (1). A simple method makes it possible to determine the values of the previously defined absolute accuracies. A simple method for example consists of measuring the distance separating the electromagnetic generator from the electromagnetic receiver in the initial state and at a given instant.
[0043] The means ME3 can also measure and calculate, from the speed VS of the sound, a temperature TA of the ambient air mass and an absolute precision PATA of said temperature determined from a correlation between the speed of the sound and the rules of correspondence tabulated in the literature between the velocity of sound and the temperature to deduce the difference PAG1R1 from the distance G1R1 and PAG2R2 of the distance G2R2 as a function of the operational conditions and / or as a function of the aerodynamic and / or mechanical stresses experienced by said aircraft (1). A simple method consists, for example, in measuring the aeroelasticity of the aircraft from the variation of the temperature. Indeed, the structure of the aircraft is designed with materials having a coefficient of thermal expansion.
[0044] Advantageously, the ME3 measurement and calculation means also calculates, based on the speed VS of the sound, using the tabulated correspondence laws connecting the speed of sound and the ambient temperature, the temperature TA of the ambient air mass. , then using the laws of expansion of the materials and the geometry of the aircraft, the ME3 means calculates the differences PAG1R1 of the distance G1R1 and PAG2R2 of the distance G2R2 as a function of the operating conditions and / or as a function of the aerodynamic constraints and or mechanical undergone by said aircraft (1). The means ME3 can also measure and calculate, from the airspeed VA and / or the atmospheric pressure, an absolute precision PAP to take account of the elongation of the aircraft as a function of the drag forces applied to the rear parts. of the aircraft in order to deduce the algebraic deviations PAG1R1 from the distance Gl R1 and PAG2R2 of the distance G2R2 as a function of the operational conditions and / or as a function of the aerodynamic and / or mechanical stresses to which said aircraft (1) is subjected. According to another operating method of the device according to the invention, the following steps are successively adopted: the positions G1 and G2 of the generators GA1 and GA2 and / or the new positions R1 and R2 of the receivers RA1 and RA2 and / or the new distance G1R1 and G2R2, depending on the operational conditions and / or depending on the aerodynamic and / or mechanical stresses experienced by said aircraft (1). the absolute accuracy of the positions PAG1 and PAG2 of the positions of the generators GA1 and GA2 respectively and / or the algebraic deviations PARI and PAR2 of the positions of the receivers RA1 and RA2 and / or the algebraic deviations PAG1R1 and PAG2R2 of the distance G1R1 and G2R2 are calculated respectively depending on the operating conditions and / or depending on the aerodynamic and / or mechanical stresses experienced by said aircraft (1), in particular taking into account aeroelasticities phenomena. the value of the airplane speed VA and the speed of the sound VS are calculated as a function of Ti, T2, G1, G2, R1, R2 and / or as a function of Ti, T2, G1R1, G2R2 by integrating the corrections PAG1, PAG2 and / or PARI, PAR2 of the positions G1, G2, R1, R2 respectively and / or the corrections PAG1R1, PAG2R2, distances G1R1, G2R2 respectively. the absolute accuracy PAVA and / or the relative precision PRVA expressed in percent, such as PRVA = 100xPAVA / VA, are calculated as a function of the operational conditions and / or as a function of the aerodynamic and / or mechanical stresses experienced by said aircraft (1 ) for the values of PAG1, PAG2 and / or PARI, PAR2 and / or PAG1R1, PAG2R2. The means ME4 is a means for measuring and calculating the electromagnetic wave travel time TEM between the generator GE and the receiver RE, and the distance GE between the generator GE and the receiver RE by following the slight deformations of the the structure of the aircraft (1) so as to obtain the algebraic deviation PAGERE of the distance GERE and to deduce the algebraic deviations PAG1R1 from the distance G1R1 and PAG2R2 of the distance G2R2 as a function of the operating conditions and / or according to the constraints aerodynamic and / or mechanical forces experienced by said aircraft (1). According to other operating methods of the device according to the invention, the following steps are successively adopted: for an operational condition and / or aerodynamic and / or mechanical stresses experienced by said aircraft (1) noted C01, the TEM time is measured of course of the electromagnetic wave between the generator GE and the receiver RE and the distance GERE is calculated - for an operational condition and / or the aerodynamic and / or mechanical stresses undergone by said aircraft (1) denoted CO2, a new measurement is measured. TEM time of travel of the electromagnetic wave between the generator GE and the receiver RE and the new distance NGERE is calculated, - the new distance NGERE is compared with the distance GERE and one deduces the algebraic deviation PAGERE = NGERE - GERE of the distance between GE and RE, the value of the airplane speed VA and of the speed of the sound VS is calculated as a function of Ti, T2, G1, G2, R1, R2 and / or as a function of Ti, T2, G1R1, G2R2 inintegrating the PAGERE correction with the values of the distances G1R1, G2R2 for an operational condition and / or aerodynamic and / or mechanical stresses experienced by said aircraft (1) denoted CO2, the algebraic deviations PAG1R1 of the distance G1R1 and PAG2R2 of the distance are deduced G2R2, the absolute accuracy PAVA and / or the relative precision PRVA expressed in percent such as PRVA = 100xPAVA / VA, are calculated as a function of the operating conditions and / or as a function of the aerodynamic and / or mechanical stresses experienced by said aircraft (1 ) CO2 for the PAGERE value obtained.
[0045] The means ME1, ME2, ME3 and ME4 correlate with each other and exchange the data to obtain a better accuracy of the value of the airspeed and / or the speed of the sound and / or the angle of incidence. These means are also correlated with the means MC1, MC2 and MC3. Also, all the means constituting the means MC are interrelated with one another and / or all the means constituting the means ME are interrelated with each other so that, for a value of the airspeed VA, one and a single measurement and / or one and only one calculation of the relative accuracy PAVA performed by the correlation of the means MC and ME. According to the invention, several techniques and / or measurement and / or active calculation systems make it possible to evaluate the relative and / or absolute accuracies on the measurement of the position of each generator and receiver and / or on the measurement and / or the calculation of the distances separating each generator to each receiver. One of the techniques consists in the use of optical linear pressure sensors adapted to the environment of the aircraft. Indeed, this type of sensor is reliable and able to locate linear positions up to 10 km or along curved paths. This makes it possible to measure in real time the position of each generator and receiver with a precision of the order of one-tenth of a micrometer. Another technique consists in the use of optoelectronic sensors adapted to the environment of the aircraft. These sensors have the possibility of being coupled to several so as to obtain, by phase comparison method, a greater accuracy, better than a micrometer, preferably a few nanometers. Another technique consists in the use of magnetostrictive sensors adapted to the environment of the aircraft. These sensors have the ability to operate without coupling with other magnetostrictive position sensors. It allows to obtain a greater precision, better than the micrometer, preferably a few nanometers. This sensor has the advantage that it uses a magnetic field with a pulse adapted to the environment of the aircraft and in particular to the environment of the radio frequencies of the airports. According to one embodiment, the receivers RA1 and RA2 and / or the generators GA1 and GA2 have an area of at least 16 square millimeters so that, structural deformations undergone by the aircraft, under the operating conditions and / or or under the effects of aerodynamic and / or mechanical stresses, are negligible and do not prevent the receivers RA1 and RA2 from receiving the wave trains emitted by the generator GAI and / or GA2. This makes it possible to minimize aeroelasticity phenomena.
[0046] Preferably, at least one acoustic generator and / or at least one acoustic receiver is placed at a point where the deformation effects, in particular the aeroelasticity experienced by the aircraft and / or the effects of the boundary layer, are substantially negligible. to accurately measure and calculate the distances separating the other acoustic generators to the other acoustic receivers and / or to accurately measure the positions of the other acoustic generators and / or other acoustic receivers. According to other embodiments of the invention, each acoustic generator and / or acoustic receiver further comprises MPT means for measuring and calculating the temperature of their operation with a certain accuracy. This MPT means also makes it possible to calculate the accuracy on the position of each acoustic generator and / or each acoustic receiver, and possibly the accuracy on measuring the distance between an acoustic generator and an acoustic receiver by using the principle of aeroelasticity of the acoustic generators. materials known from literature. The acoustic generators and / or acoustic receivers chosen for the implementation of the invention are MEMS transducers or magnetostrictive transducers, emitting in the one-third octave band centered on 25 kHz. This chosen frequency band makes it possible to determine the transmission frequencies of each generator. The basic structure of the selected generators and receivers is the key point of the entire device. For example, the generator and the receiver are formed of a matrix of 100 (10x10) identical elements able to accept a maximum power of 250 W each. Each element has been designed to cover the desired frequency range. The elements are associated in concentric rings. To control the directivity, each ring is associated with a power amplifier and a power preamplifier. This makes it possible to weight the various rings on transmission and reception in order to limit the variations of directivity on the band. The power amplifiers are tuned or untuned linear amplifiers (10 to 100 kHz); this allows great latitude in the design of acoustic signals. Each module preferably delivers 1 kW (+/- 90 V) under a very low impedance (0.1 Ohm). Given the structure of the rings, the maximum level in the axis will be a few hundred decibels: 214 decibels at 30 kHz, 215 decibels at 50 kHz and 207 decibels at 70 kHz. It is planned to correct these variations by prefiltering (pre-emphasis) on the emission of the wave train. This is easily adaptable to the extent that emitted wave trains are precalculated and stored in digital form. The directivity considerations cited are, in fact, a superposition of narrow-band views to describe a broadband system. It is true that the definition of a broadband directivity index is very complex, because the latter is a function of two variables which are the angle and the frequency. However, as a first approach, we can consider the energy emitted (or received) on a given frequency band. This distribution of energy is reduced to the directivity diagram, if one places oneself at narrow band. This energy consideration allows a totally broadband approach to the device. A device block according to the invention mainly, but not exclusively, comprises three essential parts: transducer and associated electronics, power and / or frequency amplifiers and / or impedance amplifiers, the data processing and correction unit. The associated electronics is housed in a sealed compartment; it is connected to the power, impedance, frequency, processing and correction part. This makes it possible to install the transducer on the fuselage (2) of the aircraft with a better stability, a lower noise level.
[0047] The wave train processing operations are widely known from the state of the art except for the parts described by the present invention. According to the invention, the analog preprocessing is separated by a frequency band. The filtering corresponding to the accuracy of the value of the airspeed is performed by digital filtering in real time.
[0048] The processing architecture for accurately calculating the value of the airspeed proposed by the present invention makes it possible to overcome the problems due to the widening of the working band which is that of MEMS transducers or magnetostrictive transducers, emitting in the third octave band centered on 25kHz. According to an alternative embodiment of the invention, the transducers used are piezoelectric transducers. According to other embodiments of the invention, the transducers used are magnetostrictive transducers. According to other embodiments of the invention, the transducers used are electrostatic transducers. According to other embodiments of the invention, the transducers used are CMUT transducers. According to other embodiments of the invention, the transducers used are PMUT transducers. Advantageously, at least one of the acoustic generators and / or receivers is fixed in a place where the thickness of the boundary layer is low and / or where the effects of the boundary layer are low, so that the travel time of the wave train emitted by at least one of the generators and / or received by at least one receiver in or out of the boundary layer is very small, in particular less than a predetermined value TPmax. TPmax is an arbitrary value defined according to the nature and the thickness of the boundary layer The value of TPmax is always greater than 1 microsecond to obtain a better precision on the value of the speed.
[0049] Advantageously, the sensors, in particular the generators, are placed on at least one fin placed on the fuselage (2). According to other characteristics of the invention, the device according to the invention comprises at least two electromagnetic wave generators GE1 and GE2 fixed on the structure of said aircraft at a position Ell and El2 close to the generators GA1 and GA2 respectively, in particular El1 = G1 and / or El 2 = G2, and / or at least two electromagnetic wave receivers RE1 and RE2 fixed on the structure of said aircraft at a position E21 and E22 close to the receivers RA1 and RA2 respectively, in particular Ell-R1 and / or or E 1 2 = R2. According to other embodiments of the device according to the invention, to simplify the device and to make the device according to the invention compact, the positions of at least two generators are merged G1 = G2 and / or the positions of at least two receivers are combined R1 = R2. With reference to FIG. 4 and FIG. 5, the device according to the invention comprises an acoustic generator GA12 comprising at least two acoustic generators GA1 and GA2, and / or comprises an acoustic receiver RA12 comprising at least two acoustic receivers RA1 and RA2 .
[0050] Advantageously, the positions G1 and G2 of the generators GA1 and GA2 respectively are chosen substantially in the plane of plane symmetry, in an upper part of the fuselage (2) and / or the positions R1 and R2 are chosen substantially in the airplane plane of symmetry, behind positions GA1 and GA2, in the upper part of the vertical empennage (3). The front and the back are upstream and downstream relative to the movement of the speed. In other words, the generators are placed in front of the receivers in the direction of movement of the speed VA, so they receive the mass of air first, before the receivers. According to other embodiments, the device according to the invention further comprises at least three acoustic wave generators and / or at least three acoustic wave receivers and possibly a means for measuring and calculating the incidence. anemometric from the acoustic wave travel times to obtain a better accuracy on the value of the high incidence VA speed.
[0051] According to other features of the invention, the device comprises at least one other velocity measuring means such as a Pitot tube, so as to compare speeds and obtain information redundancy. Advantageously, said other speed measuring means is placed on the structure of the aircraft, and in particular on a fin placed on the fuselage (2). According to another operating method of the device according to the invention, the following steps are successively adopted: - in addition, from the speed VS of the sound, a temperature TA of the ambient air mass and a PATA deviation of said temperature determined from a correlation between the velocity of the sound and the rules of correspondence between the velocity of the sound and the temperature, the algebraic deviations PAG1R1 of the distance G1R1 and PAG2R2 of the distance G2R2 are deduced as a function of the operating conditions and / or depending on the aerodynamic and / or mechanical stresses experienced by said aircraft (1). the value of the airplane speed VA and of the speed of the sound VS is calculated as a function of Ti, T2, G1, G2, R1, R2 and / or as a function of Ti, T2, G1R1, G2R2 for the algebraic deviations PAG1R1 of the distance GlRlet PAG2R2 of the distance G2R2, the absolute accuracy PAVA and / or the relative accuracy PRVA, expressed in percent such as PRVA = 100xPAVA / VA, are calculated as a function of the operating conditions and / or according to the aerodynamic constraints and / or mechanical forces undergone by said aircraft (1) for the values of the algebraic deviations PAG1R1 of the distance GlRlet PAG2R2 of the distance G2R2 obtained. It is clear that to obtain a value of the precise speed, the redundancy of measurement is obligatory. For this, it is mounted on an aircraft by the measurement means described above, preferably two or three speed measuring devices VA described above. Said aircraft also comprises means for comparing the values of the aircraft speeds VA respectively measured by each device so as to ensure an increased redundancy of the value of the speed VA to improve the steering accuracy of the aircraft. According to other embodiments, the aircraft, comprising the device according to the invention, further comprises a means for measuring the total pressure, for example using a Pitot tube, obtained at a location of the aircraft, so as to deduce the static pressure at infinity upstream and obtain redundancy on the measurement of the speed VA of the aircraft (1).
[0052] According to other characteristics of the invention, each sensor comprises at least one protection means adapted according to the aircraft and / or the flight range of the aircraft. This, to take into account the kinematic heating of flight conditions. Advantageously, each sensor comprises an outer envelope comprising a system for adapting to a rise in pressure, in particular accidental from an untimely decompression of the aircraft. Advantageously, the protection of the sensors may consist of a material, in particular elastomer or porous material, causing an acceleration of ultrasonic sound waves, especially when said waves pass through said material. This is to compensate for the delay that the acoustic wave may undergo when crossing the boundary layer and / or in the boundary layer. Advantageously, the sensor protection means previously mentioned is of the radome type. The invention described above has removed the doubts that the use of such a device in aircraft capable of moving in severe environments would be uncertain, if not impossible. Indeed, all the problems that are most often encountered in the design of generators and receivers have been solved physically. For example, the variation of the output of the generators and / or receivers on the selected frequency band, in particular the band of 10 kHz to 80 kHz, preferably 100 kHz, is noted: a variation of the directivity of the frequency; a variation of the adsorption of the signal, an increase in the noise level B, the real-time processing constraints of the acoustic wave train signal, - the interpretation of the data leading to the calculation of the precise value of the airspeed velocity VA of the aircraft and speed of sound VS. It can thus be seen that it is possible to produce a device for very accurate measurement, in real time, of the airspeed VA of an aircraft (1) with respect to an ambient air mass MA surrounding the aircraft, and taking into account the operational and / or atmospheric conditions, said device making it possible to determine with great precision the aircraft speed VA and the speed of the sound VS in the entire flight range of the aircraft, subsonic, transonic and supersonic, in selecting particular locations for the generator and the receiver where the boundary layer is relatively thin and respecting the prescribed minimum angles between the paths of the wave trains. It is possible knowing the actual speed of the sound and the ambient temperature to deduce the moisture content. The knowledge of this air humidity can be important for the pilot to know precisely the risk of icing. For example, if the temperature is negative and the humidity is high, the risk of icing is high. Indeed, the speed of sound in the air varies mainly with the temperature, then a little according to the humidity content in the atmosphere. Here, our acoustic system allows to know the speed of sound. A temperature measurement makes it possible to know the ambient temperature. Tables give the influence of moisture on the speed of sound. It is therefore possible to deduce the moisture content of the air knowing the actual speed of sound and temperature. For example, if the speed of sound measured by the acoustic system is equal to the speed of the theoretical sound in the air for a given temperature, then it can be deduced that the moisture content is zero.
[0053] In the nonlimiting embodiment illustrated in FIG. 4, three acoustic wave trains emitted respectively by three generators GA1, GA2, GA3 are routed to a triple receiver RA12. This receiver is designed to receive the three trains of waves one after the other, here conveyed discontinuously. The travel times of these three wave trains are respectively T1, T2, T3 and the positions of the generators are respectively Gl, G2, G3, the receiver being in position R. In this embodiment, the angles between the paths of the Wave trains (TETA and BETA) are greater than or equal to 4 degrees. It is demonstrated that if the generators and the triple receiver are substantially arranged according to FIG. 4 then it is possible to unequivocally deduce the values of the speed of the sound VS, the airspeed VA and the angle of incidence of the the aircraft, from the position coordinates of the generators and the triple receiver, and travel times Ti, T2, T3. An error calculation, in particular of the relative precision PRVA and / or of the absolute precision PAVA on the value of the airspeed, an error calculation on the value of the speed of the sound VS and the angle of incidence are fully compatible with aeronautical needs. So we see that it is possible, contrary to what was previously imagined, to calculate the speed of an aircraft or a drone relative to the ambient air mass with good accuracy (better than a tenth of percent) from the geometrical position data of generators and receivers, and this independently of other parameters such as pressure, humidity, the presence of water droplets, fog, snow, dust,. .. By comparing the calculated speed of sound by the acoustic system, with what should be the speed of sound for a temperature and considering extreme values of humidity, it is possible to verify that the system is working properly. Indeed, the speed of sound varies little according to the humidity rate (less than 100% for temperatures below 0 degrees, and a few percent at higher temperatures). The acoustic system can therefore include a self-checking function. what can not do today Pitot probes and what explains that these airspeeds are three in one aircraft.
[0054] On the other hand, it is seen that the use of conventional components having standard accuracy levels makes it possible to achieve very good accuracy on the measurement of the speed VA and leads to industrialization at very low cost. Contrary to the prejudices which consisted in believing that only the Pitot probes make it possible to accurately measure the airspeed of an aircraft, the device which is the subject of the present invention makes it possible to provide more accurate and reliable information, of anemometric airspeed. an aircraft under severe atmospheric conditions and in the presence of a multiplicity of constraints, better than those of pitot tubes. It also allows real redundancy with other conventional speed measurement systems. It also allows self-monitoring of the displayed speed. It also allows to know the humidity level of the ambient air, which with the knowledge of the temperature makes it possible to alert the pilot on the risks of icing. Those skilled in the art can apply this concept to many other similar systems without departing from the technical scope of the present invention.

权利要求:
Claims (33)
[0001]
CLAIMS1) High-precision measurement device, in real time, the airspeed VA of an aircraft (1) with respect to a surrounding air mass MA surrounding said aircraft and taking into account operational and / or atmospheric conditions, said ambient air mass MA having a direction of movement relative to the aircraft represented by a vector W going from upstream to downstream, said aircraft (1) being able to evolve in a subsonic speed domain and / or transonic and / or supersonic, and having at least one fuselage (2), at least one boundary layer CL surrounding said aircraft which has a thickness defined by an angle ALFA, said ALFA angle being defined between the outer surface of the aircraft (1) and a surface where the flow is close to the flow relative to the upstream infinity, said aircraft (1) comprising a weakly elastic structure capable of deforming slightly depending on the operating conditions and / o u atmospheric as for example depending on the aerodynamic and / or mechanical and / or thermal stresses experienced by said aircraft, said aircraft (1) being capable of generating a noise B during its displacement and / or its operation in the mass of ambient air MA, said aircraft (1) having a longitudinal axis OX, a lateral axis OY, a vertical axis OZ constituting an orthonormal coordinate system OXYZ, and comprising: at least two acoustic wave generators GA1 and GA2 capable of emitting each at least one acoustic wave train, said generators GA1 and GA2 being fixed on the structure of said aircraft (1) respectively at a position G1 and G2 in the OXYZ coordinate system, and at least two acoustic wave receivers RA1 and RA2 capable of each receive at least one wave train emitted by the acoustic wave generators GA1 and / or GA2, said receivers RA1 and RA2 being fixed on the structure of said aircraft (1) respectively at a position R1 and R2 da ns the OXYZ mark, the receiver RA1 being situated at a distance D1 of the generator GA1 on the axis OX and at a distance H1 of the generator GA1 on the axis OZ, and the receiver RA2 being situated at a distance D2 of the generator GA2 on the axis OX and at a distance H2 from the generator GA2 on the axis OZ, the said receivers RA1 and RA2 being further situated respectively downstream of the generators GA1 and GA2, characterized in that the acoustic wave generators GA1 and GA2 and the acoustic wave receivers RA1 and RA2 being fixed on the structure of said aircraft by following the slight deformations of said structure of said aircraft (1), and characterized by the presence of at least two geometric positioning factors FP1 and FP2 defining the positioning domain in the OXYZ reference frame between the generators GA1 and GA2 and the receivers RA1 and RA2, such that FP1 = D1 / H1 and FP2 = D2 / H2, and in that said positioning domain being chosen in such a way e that the geometrical positioning factor FP1 is always greater than the geometrical positioning factor FP2, and furthermore said geometrical positioning factor FP2 is comprised between a minimum value FPMIN and a predefined maximum value FPMAX, and characterized in that said wave trains transmitted by the acoustic wave generators GA1 and / or GA2 traveling from upstream to downstream following the vector W and having an acoustic frequency of between 10 kHz and 100 kHz, and characterized in that each train of wave transmitted by the generator GA1 and / or GA2 to the receiver RA1 and / or RA2 making, in addition, with the axis OX, at least one TETA angle greater than or equal to ALFA and said wave trains furthermore making them minus a BETA angle less than 90 degrees but different from zero, in a plane of the OXYZ mark, and in that the angle difference TETA-ALFA being between 0.02 degrees and a TETAmax value geometric characteristics of said aircraft.
[0002]
2) measuring device according to claim 1 characterized in that FPMIN = 0.6 and FPMAX = 8 and in that the value TETAmax is substantially equal to 75 degrees so that in the plane XOZ, the absolute value of the difference TETA - BETA is less than 90 degrees, preferably less than 75 degrees.
[0003]
3) measuring device according to claim 1 or 2 characterized in that it further comprises at least one means MC for measuring and calculating, in real time, active and automatic, the airspeed VA with an absolute accuracy PAVA or a relative accuracy PRVA expressed in percent such that PRVA = 100xPAVA / VA, said means MC comprising simultaneously: - at least one means MC1 for measuring and / or calculating the time Ti of travel of the wave train between the generator GA1 and the receiver RAI and time T2 of travel of the wave train between the generator GA2 and the receiver RA2, following the slight deformations of the structure of the aircraft (1) and - at least one means MC2 measuring and / or calculating the positions G1, G2, R1, R2 and / or distances G1R1 and G2R2 respectively corresponding to the distance between the generator G1 and the receiver R1 and at the distance between the generator G2 and the receiver G2, following the slight deformations of the structure of the aircraft (1), and at least one means for measuring and / or calculating MC3 of the airspeed VA and the speed of the sound VS as a function of Ti, T2, Gl, G2, R1, R2 and / or function of Ti, T2, G1R1, G2R2, following the slight deformations of the structure of the aircraft (1), and in that it furthermore comprises at least one ME measurement and / or calculation means, active and automatic, correction of the value of the airspeed VA and possibly the value of the speed of sound VS by improving the absolute accuracy PAVA and / or the relative accuracy PRVA expressed in percent such that PRVA = 100xPAVA / VA, depending operating conditions such as the noise and / or the aerodynamic and / or mechanical and / or thermal stresses experienced by said aircraft (1), the value of PRVA being preferably less than 1%, and in that the MC means and the ME being furthermore correlated so that for each value of Ti, T2, G1, G2, R1, R2 and / or Ti, T2, G1R1, G2R2 measured corresponds to one and only one value of VA, a value of PAVA and / or a value of PRVA.
[0004]
4) measuring device according to any one of the preceding claims characterized in that it further comprises at least one electromagnetic wave generator GE capable of emitting an electromagnetic wave train, said wave train having a frequency adapted to the aerial regulations and the required performances, said frequency being preferably between 1 GHz and 20 GHz, and at least one electromagnetic wave receiver RE capable of receiving said electromagnetic wave train emitted by said generator GE, said generator GE and receiver RE being fixed on the structure of said aircraft at a position E1 and E2 respectively, following the slight deformations of the structure of said aircraft (1), said receiver RE being located at a distance GE of the GE generator so as to measure the relative deformation of the structure of said aircraft (1) by measuring in real time the travel time of the electromagnetic wave that, regardless of the aircraft speed.
[0005]
5) Measuring device according to claim 3 characterized in that the ME means comprises at least one means ME1 for measuring and / or calculating and regulating the power PA1 and PA2 of the wave trains emitted respectively by said acoustic generators GA1 and GA2, said ME1 means further measuring the power PB of the noise B generated in the operating conditions and / or by the aerodynamic and / or mechanical and / or thermal stresses experienced by the aircraft (1) in the ambient air mass MA, said means ME1 further enabling active control of the power PA1 and / or PA2 as a function of the power PB of the noise B so that the ratio PA1 / PB and / or PA2 / PB is always greater than a value predetermined Pd depending on the operating conditions and / or aerodynamic and / or mechanical and / or thermal constraints, preferably greater than 0.7 or 1.2.
[0006]
6) Measuring device according to claim 5 characterized in that when the acoustic power PB noise B is less than a predetermined value PBm (PB <13 Bm) depending on operational conditions and / or aerodynamic and / or mechanical stresses and or thermal, for example 60 decibels, for example when the aircraft is stationary, then the power emitted by the generator GA1 and / or the generator GA2 is less than or equal to a predetermined value PGm, for example 110 decibels, and when the power PB of the noise B is greater than the predetermined value PBm (PB> PBm), the acoustic power emitted by the generator GA1 and / or the generator GA2 is equal to a value greater than said predetermined value PGm, for example 160 decibels.
[0007]
7) measuring device according to any one of claims 5 or 6 characterized in that the power PB noise B is measured at a location where the power received acoustic waves emitted by the generator GA1 and / or GA2 is low and / or the power of the noise B is measured at a time when the power of the waves emitted by the generator GA1 and / or GA2 is low or zero.
[0008]
8) measuring device according to any one of claims 3 to 7 characterized in that the ME means further comprises at least a means ME2 for measuring and calculating the frequency FA1 and FA2 and / or the impedance IA1 and IA2 acoustic wave trains emitted respectively by acoustic generators GA1 and GA2 and the frequency FB and / or impedance IB noise B generated under operational conditions and / or aerodynamic and / or mechanical constraints suffered by the aircraft (1) in the ambient air mass MA, said means ME2 further enabling active control of the frequency FA1 and / or FA2 as a function of the frequency FB of the noise B so that the ratio FA1 / FB and / or FA2 / FB is always greater than a predetermined value Fd, and / or said means furthermore making it possible to control the impedance IA1 and / or IA2 as a function of the impedance IB of the noise B so as to the ratio 1A1 / IB and / or 1A2 / 1B is always greater than one predetermined value Id.
[0009]
9) Measuring device according to any one of claims 3 to 8 characterized in that the means ME further comprises at least a means ME3 for measuring and calculating the algebraic deviations of the positions PAG1 and PAG2 of the generators GA1 and GA2 respectively and / or the algebraic deviation of the positions PARI and PAR2 of the receivers RA1 and RA2 respectively and / or the algebraic deviations PAG1R1 and PAG2R2 of the distances G1R1 and G2R2 respectively, as a function of the operational conditions and / or as a function of the aerodynamic constraints and or mechanical undergone by said aircraft (1).
[0010]
10) Measuring device according to claim 9 characterized in that the means ME3 measurement and calculation further calculates, from the speed VS of the sound, using the tabulated correspondence laws connecting the speed of sound and the ambient temperature , a temperature TA of the ambient air mass, then using the laws of expansion of the materials and the geometry of the aircraft, the ME3 means calculates the differences PAG1R1 of the distance G1R1 and PAG2R2 of the distance G2R2 as a function of the the operational conditions and / or the aerodynamic and / or mechanical stresses experienced by said aircraft (1).
[0011]
11) Measuring device according to any one of claims 9 to 10 characterized in that the means ME3 for measuring and calculating further calculates, from the airspeed VA and / or atmospheric pressure, a PAP algebraic deviation to account for the elongation of the aircraft according to the dither forces applied to the rear parts of the aircraft in order to deduce the algebraic deviations PAG1R1 from the distance G1R1 and PAG2R2 from the distance G2R2 as a function of the operating conditions and / or depending on the aerodynamic and / or mechanical stresses experienced by said aircraft (1).
[0012]
12) Measuring device according to any one of claims 9 to 11 characterized in that it further comprises means ME4 for measuring and calculating the time TEM of the electromagnetic wave travel between the generator GE and the receiver RE and the distance GERE between the generator GE and the receiver RE following the slight deformations of the structure of the aircraft (1) so as to obtain the algebraic deviation PAGERE of the distance GERE and to deduce the algebraic correction PAG1R1 of the distance G1R1 and also to deduce the algebraic correction PAG2R2 of the distance G2R2 as a function of the operating conditions and / or as a function of aerodynamic and / or mechanical stresses experienced by said aircraft (1).
[0013]
13) Measuring device according to any one of claims 3 to 12, characterized in that all the means constituting the means MC are correlated with each other and / or all the means constituting the ME means are correlated with each other.
[0014]
14) Measuring device according to any one of the preceding claims, characterized in that the receivers RA1 and RA2 and / or the generators GA1 and GA2 have an area of at least 16 square millimeters so that, structural deformations undergone by the aircraft, under the operational conditions and / or under the effects of aerodynamic and / or mechanical stresses, are negligible and do not prevent the receivers RA1 and RA2 from receiving the wave trains emitted by the generator GA1 and / or GA2.
[0015]
15) Measuring device according to any one of the preceding claims, characterized in that at least one of the acoustic generators and / or at least one of the acoustic receivers is placed at a point where the deformation effects experienced by the aircraft are substantially negligible so as to accurately measure and calculate the distances separating the other acoustic generators to the other acoustic receivers, and / or to accurately measure the positions of the other acoustic generators and / or other acoustic receivers.
[0016]
16) Measuring device according to any one of the preceding claims, characterized in that the acoustic generators and / or the acoustic receivers are MEMS transducers or magnetostrictive transducers, emitting in the one-third octave band centered on 25 kHz used to determine the frequencies of each generator.
[0017]
17) Measuring device according to any one of the preceding claims, characterized in that at least one of the generators and / or acoustic receivers is fixed at a place where the thickness of the boundary layer is relatively low and / or, where the effects of the boundary layer are relatively small, so that the travel time of the wave train emitted by said generator and / or received by said receiver in the boundary layer is very small, in particular less than a predetermined value TPmax, preferably TPmax = 0.02 seconds.
[0018]
18) Measuring device according to any one of the preceding claims, characterized in that it comprises at least two electromagnetic wave generators GE1 and GE2 fixed on the structure of said aircraft at a position Ell and El 2 close to the generators GA1 and GA2 respectively, in particular El 1 coincide with G1 and / or E12 coincide with G2, and / or at least two electromagnetic wave receivers RE1 and RE2 fixed on the structure of said aircraft at a position E21 and E22 close to the receivers RA1 and RA2 respectively , especially E21 coincide with R1 and / or E22 coincide with R2.
[0019]
19) Measuring device according to any one of the preceding claims, characterized in that the positions of at least two generators are coincident G1 = G2 or in that the positions of at least two receivers are coincident Ri = R2.
[0020]
20) Measuring device according to any one of the preceding claims, characterized in that it comprises an acoustic generator GA12 comprising at least two acoustic generators GA1, GA2 and / or an acoustic receiver RA12 comprising at least two acoustic receivers RA1, RA2 .
[0021]
21) Measuring device according to any one of the preceding claims, characterized in that the positions G1 and G2 are chosen substantially in the plane of plane symmetry, in an upper part of the fuselage (2) and / or the positions R1 and R2 are selected substantially in the airplane plane of symmetry, downstream of positions GA1 and GA2, in the upper part of the vertical tail.
[0022]
22) Measuring device according to any one of the preceding claims, characterized in that it comprises at least three acoustic wave generators and / or at least three acoustic wave receivers and possibly a means for measuring and calculating the airspeed incidence from the acoustic wave travel times so as to obtain an accurate value of the incidence and a better accuracy on the value of the high incidence velocity VA.
[0023]
23) A method for implementing the measuring device according to any one of claims 3 to 22 wherein: at least two wave trains are emitted respectively by the acoustic generator GA1 and GA2 respectively to RA1 and RA2 receivers respectively the receiver RA1 receives at least one wave transmitted by GA1 and the receiver RA2 receives at least one wave transmitted by GA2, from the means MC, the travel times of the wave trains T1 and T2 are measured, and or measure, from the positions G1, G2, R1, R2, the distances G1R1 and G2R2, the value of the airplane speed VA and the speed of the sound VS are calculated as a function of Ti, T2, Gl, G2, R1, R2 and / or as a function of T1, T2, G1R1, G2R2;
[0024]
24) The method of claim 23 wherein: - the value of the power PA1 and / or PA2 of the wave trains emitted by the acoustic generators and the power PB of the ambient noise B is measured and the ratio PA1 / PB is calculated and / or PA2 / PB, - it is verified: o if the ratio PA1 / PB and / or PA2 / PB is greater than the predetermined value Pd as a function of the operating conditions and / or as a function of the aerodynamic and / or mechanical stresses experienced by said aircraft (1) in the air mass MA, the value of the power PAlet / or PA2 is kept constant, o if the ratio PA1 / PB and / or PA2 / PB is less than or equal to the value Pd, then substantially the value of the power PA1 and / or PA2 so as to obtain a ratio PA1 / PB and / or PA2 / PB greater than Pd, - the value of the airspeed VA and the speed of the sound VS are corrected as a function of Ti , T2, G1, G2, R1, R2 and / or as a function of Ti, T2, G1R1, G2R2 for the power value PA1 and / or PA2, it is calculated e the absolute accuracy PAVA and / or the relative accuracy PRVA expressed in percent such that PRVA = 100xPAVA / VA, depending on the operational conditions and / or depending on the aerodynamic and / or mechanical stresses experienced by said aircraft (1) for the power value PA1 and / or PA2.
[0025]
25) A method according to any one of claims 23 to 24 wherein: the frequency FA1 and / or FA2 of the acoustic wave trains emitted by the acoustic generators and the frequency FB of the ambient noise B are measured, and the ratio is calculated frequencies FA1 / FB and / or FA2 / FB, - it is verified: o if the ratio FA1 / FB and / or FA2 / FB is greater than Fd, then the values of FA1 and / or of FA2 are kept constant, o if the ratio FA1 / FB and / or FA2 / FB is less than or equal to Fd, the value of the frequency FA1 and / or FA2 is substantially increased so as to obtain a ratio FA1 / FB and / or FA2 / FB greater than Fd, the new value of the airplane speed VA and of the speed of the sound VS is calculated as a function of Ti, T2, G1, G2, R1, R2 and / or as a function of Ti, T2, G1R1, G2R2 for the value of the frequency FA1 and / or FA2; the absolute accuracy PAVA and / or the relative precision PRVA expressed in percent, such as PRVA = 100xPAVA / VA, are calculated as a function of the operational conditions and / or as a function of the aerodynamic and / or mechanical stresses experienced by said aircraft (1 ) for the value of the frequency FA1 and / or FA2.
[0026]
26) Method according to any one of claims 23 to 25 wherein: - the impedance IA1 and / or IA2 is measured acoustic wave trains emitted by the acoustic generators and the impedance IB ambient noise B, and calculates the ratio of the impedances IA1 / IB and / or 1A2413, one verifies: o if the ratio IA1 / 113 and / or 1A2 / I13 is superior to Id, then one keeps constant the values of IA1 and / or IA2, o if the ratio IA1 / D3 and / or IA2 / 113 is less than or equal to Id, the value of the frequency IA1 and / or IA2 is substantially increased so as to obtain a ratio IA1 / IB and / or 1A2 / 113 greater than Id respectively, - the new value of the airplane speed VA and the speed of the sound VS are calculated as a function of Ti, T2, G1, G2, R1, R2 and / or as a function of Ti, T2, G1R1, G2R2 for the value of the frequency IA1 and / or IA2, the absolute accuracy PAVA and / or the relative accuracy PRVA expressed in percent are calculated, such that PRVA = 100xPAVA / VA, depending on the conditions. and / or according to the aerodynamic and / or mechanical stresses experienced by said aircraft (1) for the value of the frequency IA1 and / or IA2.
[0027]
27) Method according to any one of claims 23 to 25 wherein: the positions G1 and G2 of the generators GA1 and GA2 and / or the new positions R1 and R2 of the receivers RA1 and RA2 and / or the new distance G1R1 and G2R2, depending on the operational conditions and / or depending on the aerodynamic and / or mechanical stresses experienced by said aircraft (1), the algebraic deviations PAG1 and PAG2 of the positions of the generators GA1 and GA2 respectively and / or the PARI algebraic deviations are calculated. and PAR2 of the positions of the receivers RA1 and RA2 and / or the algebraic deviations PAG1R1 and PAG2R2 of the distances G1R1 and G2R2 respectively as a function of the operational conditions and / or as a function of the aerodynamic and / or mechanical stresses experienced by said aircraft (1), calculates the value of the aircraft speed VA and the speed of the sound VS as a function of Ti, T2, G1, G2, R1, R2 and / or as a function of Ti, T2, G1R1, G2R2 by integrating the corrections PAG1 , PAG2 and / or PARI, PAR2 of the positions G1, G2, R1, R2 respectively and / or the corrections PAG1R1, PAG2R2, distances G1R1, G2R2 respectively. the absolute accuracy PAVA and / or the relative accuracy PRVA expressed in percent, such as PRVA = 100xPAVA / VA, are calculated as a function of the operational conditions and / or as a function of the aerodynamic and / or mechanical stresses experienced by said aircraft (1) for the values of PAG1, PAG2 and / or PARI, PAR2 and / or PAG1R1, PAG2R2.
[0028]
28) A method according to any one of claims 23 to 27 wherein: - for an operational condition and / or aerodynamic and / or mechanical stresses undergone by said aircraft (1) noted C01, measuring the travel time TEM of the an electromagnetic wave between the generator GE and the receiver RE and the distance GERE is calculated, for an operational condition and / or aerodynamic and / or mechanical stresses experienced by said aircraft (1) denoted CO2, a new travel time TEM is measured of the electromagnetic wave between the generator GE and the receiver RE and the new distance NGERE is calculated, - one compares the new distance NGERE with the distance GERE and one deduces the algebraic deviation PAGERE = NGERE - GERE of the distance between GE and RE, the value of the airplane speed VA and the speed of the sound VS are calculated as a function of Ti, T2, G1, G2, R1, R2 and / or as a function of Ti, T2, G1R1, G2R2 by integrating the correction. PAGERE to the values of distances G1R1, G2R2 for an operational condition and / or aerodynamic and / or mechanical constraints experienced by said aircraft (1) denoted CO2, an algebraic deviation PAG1R1 of the distance G1R1 and an algebraic deviation PAG2R2 of the distance G2R2 are deduced after several iterations are obtained the precise values of VA, VS, depending on the operational conditions and / or depending on the aerodynamic and / or mechanical stresses experienced by said aircraft (1) CO2 for the PAGERE value obtained.
[0029]
29) A method according to any one of claims 23 to 28 wherein: is further calculated from the speed VS of the sound, a temperature TA of the ambient air mass and a PATA deviation of said temperature determined from of a correlation between the velocity of the sound and the rules of correspondence between the speed of sound and the temperature one derives the algebraic deviation PAG1R1 from the distance GlRlet the algebraic deviation PAG2R2 of the distance G2R2 as a function of the operating conditions and / or depending on the aerodynamic and / or mechanical stresses experienced by said aircraft (1). the value of the airplane speed VA and the speed of the sound VS are calculated as a function of Ti, T2, G1, G2, R1, R2 and / or as a function of Ti, T2, G1R1, G2R2 for the algebraic deviations PAG1R1 of the distance G1R1 and PAG2R2 of the distance G2R2, the absolute accuracy PAVA and / or the relative precision PRVA, expressed in percent such as PRVA = 100xPAVA / VA, are calculated as a function of the operating conditions and / or as a function of the aerodynamic constraints and / or mechanical undergone by said aircraft (1) for the values of the algebraic deviation PAG1R1 of the distance G1R1 and the algebraic deviation PAG2R2 of the distance G2R2 obtained.
[0030]
30) Aircraft characterized in that it comprises at least one claimed device according to any one of claims 1 to 22, and in that it further comprises a Pitot tube for measuring the total pressure at a location of the aircraft in order to deduce the static pressure at infinity upstream and / or obtain a redundancy on the measurement of the speed VA of the aircraft (1).
[0031]
31) Aircraft according to claim 30 characterized in that, one of the acoustic wave generators is placed in alignment with the Pitot tube, just behind it, so as not to create additional halftone and to emit the wave acoustic outside the boundary layer.
[0032]
32) Aircraft according to any one of claims 30 to 31 characterized in that one of the acoustic wave generators is placed in the alignment of an electromagnetic communication antenna, just behind it so as not to create additional raster and emit the acoustic wave outside the boundary layer.
[0033]
33) Aircraft according to any one of claims 30 to 32, characterized in that it comprises at least one means for comparing the values of the aircraft speeds VA measured so as to ensure an increased redundancy of the value of the speed VA to improve the accuracy and safety of flying the aircraft.

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同族专利:

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公开号 | 公开日

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FR3027398B1|2017-12-15|

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EP3218726A2|2017-09-20|

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WO2016062929A3|2017-07-13|

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WO2016062929A2|2016-04-28|

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EP3218726B1|2021-03-10|

引用文献:

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公开号 | 申请日 | 公开日 | 申请人 | 专利标题

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US2699677A|1949-01-18|1955-01-18|Ferranti Ltd|Velocity measuring apparatus|

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US20120173191A1|2011-01-03|2012-07-05|Moeller Lothar B|Airspeed And Velocity Of Air Measurement|

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WO2012150385A1|2011-05-04|2012-11-08|Aer|Acoustic velocimeter|EP3633388A1|2018-10-05|2020-04-08|Rosemount Aerospace Inc.|Aircraft freestream data systems|

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EP3712620A1|2019-03-21|2020-09-23|Rosemount Aerospace Inc.|Acoustic air data sensing system with skin friction sensor|

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WO2020240104A1|2019-05-29|2020-12-03|Aer|Miniaturised ultrasonic electroacoustic capacitive transducer operating at high voltage|

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WO2020240103A1|2019-05-29|2020-12-03|Aer|Method for manufacturing a miniaturized electroacoustic emitter|

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FR3103282A1|2019-11-18|2021-05-21|Robert Schegerin|Device and method for obtaining the total temperature of the ambient air surrounding an aircraft|US3222926A|1961-07-10|1965-12-14|Boeing Co|Air mass relative motion meter|

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FR2948458B1|2009-07-24|2011-12-09|Thuries Edmond Emile|MEASURING THE SPEED OF AN AIRCRAFT IN RELATION TO AIR, INSENSITIVE TO WEATHER CONDITIONS|US10884016B2|2018-07-13|2021-01-05|Rosemount Aerospace Inc.|Low profile air data system architecture|

法律状态:
2015-08-31| PLFP| Fee payment|Year of fee payment: 2 |

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2016-04-22| PLSC| Publication of the preliminary search report|Effective date: 20160422 |

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2016-09-08| PLFP| Fee payment|Year of fee payment: 3 |

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2017-07-11| PLFP| Fee payment|Year of fee payment: 4 |

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2018-10-16| PLFP| Fee payment|Year of fee payment: 5 |

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2019-10-31| PLFP| Fee payment|Year of fee payment: 6 |

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2020-10-30| PLFP| Fee payment|Year of fee payment: 7 |

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2021-09-28| PLFP| Fee payment|Year of fee payment: 8 |

优先权:

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申请号 | 申请日 | 专利标题

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FR1402359A|FR3027398B1|2014-10-21|2014-10-21|DEVICE FOR MEASURING HIGH PRECISION OF THE SPEED OF A MOBILE IN RELATION TO A FLUID THE ENVIRONANT|FR1402359A| FR3027398B1|2014-10-21|2014-10-21|DEVICE FOR MEASURING HIGH PRECISION OF THE SPEED OF A MOBILE IN RELATION TO A FLUID THE ENVIRONANT|

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PCT/FR2015/000194| WO2016062929A2|2014-10-21|2015-10-13|Device for the high-precision measurement of the speed of a moving vehicle in relation to a surrounding fluid|

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EP15851918.1A| EP3218726B1|2014-10-21|2015-10-13|Device for the high-precision measurement of the speed of a moving vehicle in relation to a surrounding fluid|