• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The radar comprises: - a secondary antenna (1) composed of a set of columns of radiating elements each placed in a vertical plane, said antenna comprising a microwave distribution circuit columns to form a sum sum (Σ) and a path difference in azimuth; - Transmission means (3, 6) and means (2) for generating interrogation signals, said signals being transmitted via said antenna (1) to a target; receiving means (4, 6) and means (5) for processing the signals received via said antenna (1) in response to said interrogation signals, said processing means calculating the azimuth location of said target from the signals received by the sum and difference channels in azimuth, an altitude information of said target being encoded in the received signals; a circuit (31) for microwave distribution of the lines formed by the radiating elements of the different columns, said lines being situated in a horizontal plane in order to produce a difference in elevation channel, the processing means (5) calculating (4) the altitude of said target from the signals received by said elevation difference channel.
    公开号:FR3023009A1
    申请号:FR1401425
    申请日:2014-06-26
    公开日:2016-01-01
    发明作者:Philippe Billaud；Leon Dupont
    申请人:Thales SA；
    IPC主号:
    专利说明:

    [0001] SECONDARY RADAR The present invention relates to a secondary radar, it is particularly applicable to secure air traffic near the airports.
    [0002] The increase in traffic approaching airports induces a reconciliation of aircraft. In the approach phase of the airport, planes are tightening naturally and altitude differences between aircraft are decreasing. An altitude measurement error can therefore have serious consequences. In secondary radar, the altitude of an aircraft is transmitted to the radar via code C by the transponder of the aircraft. It is therefore information received by the interrogator and not a measurement conventionally performed by a primary radar. This information can therefore be tainted by error. However, the S mode with its error correcting code limits the probability of occurrence. Nevertheless, the altitude is a measurement made aboard the aircraft by the altimeter from the atmospheric pressure. Following the phase of the flight, approaching or en route, the pilot compensates the altimeter value with the standard pressure 1013.2 mbar (en route) or the pressure QNH (approaching). This results in the possibility of human error, on the part of the pilot, or material error, on the part of the altimeter in particular. The sources of error can in fact be multiple: error on the reference pressure, error on the entry of the reference pressure, bad local barometric measurement, malfunction of the probe in particular.
    [0003] It should be noted that depending on the local atmospheric pressure, a real uncertainty ranging for example up to +/- 400 meters can occur. Thus, a technical problem to be solved is to secure the information transmitted by a plane in mode C from the atmospheric pressure measured by the edge altimeter.
    [0004] An object of the invention is in particular to solve this technical problem, reliably and economically. For this purpose, the subject of the invention is a secondary radar, comprising at least: a secondary antenna composed of a set of columns of radiating elements each placed in a vertical plane, said antenna comprising a vertical microwave distribution circuit, by column, signals received by the radiating elements 19 of said column and a horizontal microwave distribution circuit of the columns to form a sum channel (E) and an azimuth difference channel (A AZI); transmission means and interrogation signal generating means, said signals being transmitted via said antenna to a target; receiving means and signal processing means received via said antenna in response to said interrogation signals, said processing means calculating the azimuth location of said target from the signals received by the sum and difference channels in azimuth, a altitude information of said target being encoded in the received signals; said radar further comprising a microwave distribution circuit combining: - the vertical microwave distribution of the signals from the radiating elements by amplitude and phase weighted summation to form a signal difference in elevation (A_ELEV ') per column and; the horizontal microwave distribution of the difference signals in elevation (A_ELEV ') of the different columns received by their radiating elements, by amplitude and phase weighted summation in order to form an elevation difference channel (A_ELEV) in the beam direction of said antenna, the processing means calculating the altitude of said target from the comparison of the signals received by said sum channel (E) and said elevation difference channel (A_ELEV). In a possible embodiment, the processing means compare the altitude value given by said information transmitted by the received signal with the calculated altitude value, an indication of potential altitude error being emitted when said difference between the two values is greater than a given threshold when detecting a target such as a radar plot message. An alert is emitted for example for a given target when the occurrence of said difference is greater than the given threshold beyond a given number of consecutive antenna turns. Said microwave distribution circuits are for example implanted on said antenna, a rotating joint RF wafer transmitting the signals of said difference in elevation channel to reception circuits dedicated to said channel. The altitude information is for example transmitted via a code C. The interrogation signal is for example of the SSR, Mode S or IFF type.
    [0005] Said radar comprises, for example, detection means able to exploit the difference in azimuth or elevation of the responses coming from two close targets to detect the presence of said targets. Advantageously, it integrates, for example, a reception function of the "squitter" ADS-B by said sum diagram E and by the control diagram CONT, the interrogations being adapted to exchanges ADS-B. Other features and advantages of the invention will become apparent from the description which follows, given with reference to the appended drawings which represent: FIG. 1, an architecture of a secondary radar according to the prior art; FIGS. 2a, 2b and 2c, a method for obtaining the sum and difference channels in azimuth according to the prior art; FIG. 3, an exemplary architecture of a secondary radar according to the invention; FIGS. 4a and 4b, an example of a secondary antenna with a possible way of obtaining the sum and difference in elevation channels; Figure 5 is an illustration of the antenna patterns sum and differences in elevation; FIG. 6, an example of exploitation of a radar according to the invention. Figure 1 illustrates the architecture of a secondary radar according to the prior art. The radar comprises an antenna SSR 1, or IFF for example, constituted by parallel bars or columns located substantially in a vertical plane, each bar being itself constituted by radiating elements. In a typical embodiment, the antenna comprises 35 columns, each column comprising 11 radiating elements. Thus, a wide vertical aperture antenna, called LVA ("wide vertical aperture"), has a width of the order of 9 meters, and a height of about one meter. Antenna 1 provides interrogation radiation at 1030 MHz and the capture of responses at 1090 MHz from transponders on board aircraft. The other units making up the radar include the following: a space-time management unit 2, generating the secondary mode S interrogations according to the tasks to be performed with the predicted targets present in the main lobe, this entity notably elaborates the SSR interrogations, MS and IFF as well as ISLS queries; a transmitter 3, converting into high power RF signals the interrogations to be radiated by the antenna 1; a receiver 4, demodulating the RF signals received by the antenna 1; a signal and data processing unit 5, detecting and decoding the received responses in the main lobe of the antenna; an RF unit 6 transferring the RF signals to and from the antenna patterns, for this purpose it conventionally comprises microwave circulators 601, 602, 603 routing the transmission and reception signals to and from the antenna. In the current radars, conventionally the diagrams used are: In emission, the sum E and CONT control diagrams, for the interrogation of the planes in the main lobe of the antenna; In reception, the sum sum E and CONT control for the detection of the responses in the main lobe and the A_AZI azimuth difference channel for the fine localization of the target in the main lobe of the antenna. The A_AZI channel can also be used for the detection in case of tangled replies35 The main functions of the RF unit 6 are the circulators 601, 602, 603 and conventionally the phase shifter 605 allowing the phasing of the signals received on the sum E diagrams. and difference in azimuth A_AZI. Once transposed into baseband by the receiver 4, the signals coming from the sum channels E, CONT (sometimes A_AZI) are used by the signal processing unit 5 to detect the responses of the transponders present in the main lobe, then to establish for each response the misalignment of the response in the main lobe in azimuth. This is done by exploiting the signals of the sum channel E and simultaneously those coming from the difference channel A_AZI, by the function conventionally called "monopulse in azimuth". At the data processing stage 5, the responses received are assembled to form a pad and the azimuthal position of the target thus detected is calculated from the position of the antenna axis and the misalignment of each response (monopulse). of azimuth) retained to constitute the stud. FIGS. 2a, 2b and 2c illustrate a possible way of obtaining the channels E and the difference in azimuth h, _AZI according to the prior art. Figure 2a illustrates lobe formation in elevation I '. More particularly, it represents a column 10 of radiating elements 19 and a vertical distributor 40, or microwave distribution circuit. The radiating elements 19 are connected to the distributor 40. The latter produces the lobe in elevation E 'by amplitude and phase weighting of the signals of each radiating element 19. A signal E' is thus produced for each column 10. FIG. the realization of the sum diagrams E, difference in azimuth A_AZI and control CONT. These diagrams are conventionally carried out by means of a horizontal distributor 21, from the E 'signals of the amplitude and phase weighted columns and the back column for the CONT channel. FIG. 2c presents, by two curves 28, 29, the antenna patterns as a function of the azimuth angle θ. A first curve 28 represents the sum diagram E whose maximum corresponds to the direction of the normal 20 at the antenna. at the level of the central column, this diagram E 35 being symmetrical with respect to the normal 20. A second curve 29 represents the difference channel AAZI in azimuth, symmetrical with respect to the normal of the antenna, presenting a value substantially zero in the direction of the normal. As is well known, the A_AZI difference channel makes it possible to precisely locate the targets in azimuth in the main lobe of the antenna (function called azimuth monopulse). FIG. 3 illustrates a possible architecture of a radar according to the invention. Advantageously, the invention uses the vertical dimension of the secondary antenna 1, that is to say its height, to form a difference in elevation way. The height is sufficient to perform an elevation measurement of sufficient accuracy, using the device according to the invention, to make altitude measurements of aircraft approaching the airports to validate the altitude information, expected by the ATC controller according to the pressure correction instructions 1013.2 mbar or QNH, transmitted via the C code or any other message.
    [0006] More precisely, advantageously, a radar according to the invention makes a measurement of the elevation of an airplane from the same responses as those used for the detection and decoding of the C code in SSR as in S mode as in IFF. There is therefore no additional transaction to increase the reliability of the C code information, since it is the signal carrying the C code that is used to perform the elevation measurements. This measurement is performed on the basis of a monopulse elevation function, in a manner totally analogous to the monopulse azimuth function. Thus, each response received from the target, the aircraft, regardless of its content (A code, C code, S mode message, IFF identification in particular), to measure the elevation of the target. The radar architecture of FIG. 3 repeats the elements of the radar architecture of FIG. 1 by adding the elements necessary for the realization of the difference in elevation path. The conventional functions of a secondary radar, as described in relation to FIG. 1, are not modified, the elevation measurement function is added in parallel with the existing functions. The elements to be added are described below. A new horizontal distributor 31, made on the antenna, makes it possible to form the difference diagram in elevation A_ELEV.
    [0007] Figures 4a and 4b illustrate the realization of this difference in elevation diagram. FIG. 4a has the same column 10 of radiating elements 19 as that of FIG. 2a, but according to the invention, the radiating elements 19 are now divided into two groups 48, 49 to form an elevation difference channel A_ELEV '. For this purpose, a first group 48 comprises for example four radiating elements connected to a first splitter 41 and a second group 49 comprises for example seven radiating elements connected to a second splitter 42. The outputs of these splitter boxes 41, 42 are themselves connected to a third distributor 43. These distributors 41,42, 43 make it possible to realize the same sum diagram E 'in elevation and the difference diagram in elevation A_ELEV' by weighting in amplitude and phase of the signals of each radiating element 19. Advantageously, it is not necessary to modify the existing architecture. Figure 4b illustrates the formation of the difference diagram in elevation A ELEV. More particularly, FIG. 4b shows the first horizontal splitter 21 already presented with respect to FIG. 2b and the new splitter 31. As in the architecture presented in FIG. 2b, the first splitter produces the sum diagrams E, difference in azimuth A_AZI and control CONT. The second splitter 31 realizes the A_ELEV diagram from the A_ELEV 'signals of the amplitude and phase-weighted columns according to a law that is almost identical to that applied in the splitter 21 for the E-diagram.
    [0008] FIG. 5 illustrates antenna diagrams obtained by means of this additional distributor 31, by curves representative of the antenna gain. A first curve 51 represents the sum diagram E 'almost identical to that obtained with the device 2a and a second curve 52 represents the difference in elevation diagram A_ELEV. Referring back to FIG. 3. The new horizontal distributor 31 being placed on the antenna, an additional RF wafer, not shown, is provided at the rotary joint for transferring the microwave signals between the antenna 1 and the rest of the circuits which are fixed.
    [0009] A circulator 32 makes it possible to direct the signals of the channel A_ELEV, in reception towards the treatment A phase-shifter 33 ensures the phasing of the signals emitted on the sum channel E and on the difference channel A_ELEV. The signals of the A_ELEV channel 5 are also transposed into baseband by the reception means 4. At the signal processing stage 5, the detected responses are now enriched, in addition to the azimuth misalignment, of the response in the main lobe. of the response in the main lobe in elevation by exploiting the signals of the sum channel E and simultaneously those from the difference channel A ELEV by the monopulse type function, which can be called a monopulse of elevation 34 by similarity with the classic monopulse function in azimuth. The responses received, assembled by the extractor 7 at the signal processing stage to constitute the stud, are now also used to constitute the elevation of the target thus measured from the misalignment in the main lobe in elevation of each response retained. to constitute the plot. Figure 6 illustrates an aspect of the processing performed by a radar according to the invention. An interrogation signal 61 is transmitted via the antenna 1. In response, an aircraft 62 returns, via its transponder, a response 63 of SSR type, Mode S or IFF in particular, most of the responses containing the code C conveying the barometric altitude information. This response is picked up by the antenna 1. The received signals are transmitted to the processing means as previously described. Conventionally, the processing means 25 perform a 2D measurement of the position of the aircraft (distance and azimuth), in particular from the sum diagram and from the azimuthal position of the main beam of the antenna completed by the measurement resulting from the difference diagram. in azimuth A_AZI. According to the invention, the processing means elaborate an attribute to the response received, this attribute giving an altitude information of the aircraft by using the difference-in-elevation diagram A_ELEV. The radar thus makes a measurement of the altitude of the aircraft from the same responses as those used for detection in SSR as in S or IFF mode. As indicated above, there is therefore no additional transaction to increase the reliability of the C code information, but in addition there is synchronization since it is the signal conveying this C code that is used to perform the elevation measurements. The altitude information obtained by the measurement of the distance and the elevation ELEV of the target can be compared with the altitude information transmitted by the code C, decoded elsewhere, and coming from the altimeter of the plane. To compare the altitude transmitted via the code C and the altitude calculated by means of the elevation difference pathway, the processing means compare the difference between the altitudes at a given threshold characterizing the appearance of a potential altitude error. which can be indicated in the plot message delivered by the radar for each detected target. The invention therefore advantageously makes it possible, with a very small additional cost of equipment, to secure the altitude information transmitted from the aircraft. The low height of the secondary antenna 1 does not make it possible to obtain precise information at altitude, but this accuracy is sufficient to confirm the altitude information provided by the planes, especially when approaching the airports where the precision is then enough. To validate the altitude information transmitted by a given target, one can take into account measurements made with it on several antenna towers. In particular, to validate a false altitude information provided by the code C, different from the altitude measured by the radar, the radar processing means verify this difference over several antenna turns. In case of confirmation of the error, an alert can be transmitted to the pilot by the air traffic control, to order for example the pilot to change altimeter or check the taking into account of the controller's instruction (1013.2 mbar or QNH). Any other action that can be taken elsewhere. Since the elevation information has sufficient accuracy when approaching the airports, the invention also makes it possible to improve the resolution of nearby targets by also detecting the targets on the difference diagram in elevation D ELEV as is currently done on some SRR, Mode S or IFF radar treatments with the azimuth diagram. Indeed, two entangled responses (close distances) if they are of the same signal level are not distinguishable on the detection path E. On the other hand, if the aircraft which are the sources of these responses have a sufficient difference in azimuth or by the shape of these two diagrams having a zero at the center of the lobe (represented by the second curve 52 of FIG. 5), the responses resulting from the azimuth difference diagrams A AZI and / or elevation A ELEV are then of different levels. which then makes it possible to detect them. With reference to FIG. 5, the radar detection means 8 then exploit the level difference brought by the zero at the center of the A_ELEV lobe, represented by the second curve 52. Moreover, if the radar integrates the message reception function. radar asynchronously transmitted periodically by the targets equipped with Mode S and IFF transponders (referred to in the literature as squitter) ADSB by the current antenna diagrams E and CONT, the difference diagram in elevation ELEV can be reproduced identically to that of the E-channel, this time for the CONT channel, this time using in addition the rear dipole and thus making it possible to measure the elevation of the ADS-B squitter in a similar manner in a similar way and thus to be able to check the coherence between the barometric altitude or GPS information that it transmits with the value measured by the radar. 20
    权利要求:
    Claims (8)
    [0001]
    REVENDICATIONS1. Secondary radar, comprising at least: a secondary antenna (1) composed of a set of columns (10) of radiating elements (19) each placed in a vertical plane, said antenna comprising a circuit (40) of vertical microwave distribution, by column, signals received by the radiating elements 19 of said column and a horizontal microwave distribution circuit (21) of the columns (10) to form a sum channel (E) and an azimuth difference channel (A_AZI); Transmission means (3, 6) and means (2) for generating interrogation signals (61), said signals being transmitted via said antenna (1) to a target (62); reception means (4, 6) and processing means (5) of the received signals (63) via said antenna (1) in response to said interrogation signals (61), said processing means (50) calculating the location in azimuth of said target (62) from the signals received by the sum and difference channels in azimuth, an altitude information of said target being coded in the received signals (63); characterized in that said radar further comprises a microwave distribution circuit (31) combining: - the vertical microwave distribution of the signals from the radiating elements (19) by weighted summation in amplitude and phase to form a signal difference in elevation (A_ELEV ' ) by column (10), and; the horizontal hyperfrequency distribution of the difference signals in elevation (A_ELEV ') of the different columns (10) received by their radiating elements (19), by weighted amplitude and phase summation in order to form an elevation difference channel (A_ELEV) in the direction the beam of said antenna, the processing means (5) calculating the altitude of said target from the comparison (4) of the signals received by said channel Sum (E) and said elevation difference channel (A_ELEV).
    [0002]
    2. Secondary radar according to claim 1, characterized in that the processing means (5) compare the altitude value given by said information transmitted by the received signal with the calculated altitude value (4), an indication of potential altitude error being emitted when said difference between the two values is greater than a given threshold when detecting a target such as a radar plot message.
    [0003]
    3. Secondary radar according to claim 2, characterized in that an alert is issued for a given target when the occurrence of said difference is greater than the given threshold beyond a given number of consecutive antenna towers.
    [0004]
    4. Secondary radar according to any one of the preceding claims, characterized in that said microwave distribution circuits (31, 41, 42, 43) are implanted on said antenna, a rotary joint RF wafer transmitting the signals of said difference channel. in elevation to reception circuits (32, 33, 4) dedicated to said channel.
    [0005]
    5. Secondary radar according to any one of the preceding claims, characterized in that the altitude information is transmitted via a code C.
    [0006]
    6. Secondary radar according to any one of the preceding claims, characterized in that the interrogation signal is SSR, Mode S or IFF type.
    [0007]
    7. Secondary radar according to any one of the preceding claims, characterized in that it comprises detection means (8) able to exploit the difference in azimuth or elevation of the responses from two nearby targets to detect the presence of said targets. .
    [0008]
    8. Secondary radar according to any one of the preceding claims, characterized in that it integrates a reception function of the "squitter" ADS-B by said sum diagram E and the control diagram CONT, the interrogations being adapted to exchanges ADS-B.
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    同族专利:
    公开号 | 公开日
    EP2960671A1|2015-12-30|
    ES2614493T3|2017-05-31|
    EP2960671B1|2016-11-09|
    FR3023009B1|2016-10-14|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    EP0577520A1|1992-07-03|1994-01-05|Thomson-Csf|Antenna for a secondary radar in S-mode|
    WO2001086319A2|2000-05-09|2001-11-15|Advanced Navigation & Positioning Corporation|Vehicle surveillance system|
    FR2965063A1|2010-09-21|2012-03-23|Thales Sa|METHOD FOR EXTENDING THE TIME OF ILLUMINATION OF TARGETS BY SECONDARY RADAR|
    CN106199531A|2016-06-27|2016-12-07|芜湖航飞科技股份有限公司|A kind of airway traffic control radar secondary radar data control system|
    FR3082949B1|2018-06-25|2020-06-26|Thales|METHOD FOR DETECTING AND LOCATING FALSE ADS-B TARGETS AND SECONDARY RADAR SYSTEM USING SUCH A METHOD|
    US20220026565A1|2018-11-23|2022-01-27|James Harvey|Air traffic control antenna and system|
    FR3090122B1|2018-12-18|2020-11-27|Thales Sa|Azimuth precision measurement method and diagrams of the main antenna lobe of a secondary radar, and radar implementing such a method|
    RU2742944C1|2020-05-12|2021-02-12|Российская Федерация, от имени которой выступает Министерство обороны Российской Федерации|System for determining coordinates of target|
    RU2742945C1|2020-05-12|2021-02-12|Российская Федерация, от имени которой выступает Министерство обороны Российской Федерации|Method of determining coordinates of target in request-response system|
    法律状态:
    2015-06-08| PLFP| Fee payment|Year of fee payment: 2 |
    2016-01-01| PLSC| Search report ready|Effective date: 20160101 |
    2016-05-26| PLFP| Fee payment|Year of fee payment: 3 |
    2017-05-30| PLFP| Fee payment|Year of fee payment: 4 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1401425A|FR3023009B1|2014-06-26|2014-06-26|SECONDARY RADAR|FR1401425A| FR3023009B1|2014-06-26|2014-06-26|SECONDARY RADAR|
    EP15172811.0A| EP2960671B1|2014-06-26|2015-06-19|Secondary radar|
    ES15172811.0T| ES2614493T3|2014-06-26|2015-06-19|Secondary radar|
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