• 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 method uses an ESM receiver network (21, 22). It comprises: a step of calculating a first geometrical shape from a first measurement giving an arrival angle difference information of said emission beam on two receivers (21, 22), said first geometric form having the points of the space giving the same first measurement on said two receivers (21, 22); a step of calculating a second geometrical shape from a second measurement giving arrival direction information on at least one receiver (21, 22), said second geometric shape comprising the points of the space giving the same second measurement on said receiver (21, 22); a step of calculating the position of the source (1), said position being the intersection of said first geometrical shape and said second geometrical shape.
    公开号:FR3037659A1
    申请号:FR1501253
    申请日:2015-06-17
    公开日:2016-12-23
    发明作者:Jean Francois Grandin；Hugo Seute；Raphael Sperling；Laurent Ratton
    申请人:Thales SA；
    IPC主号:
    专利说明:

    [0001] METHOD FOR LOCATING AN ELECTROMAGNETIC TRANSMISSION SOURCE AND SYSTEM IMPLEMENTING SAID METHOD
    [0002] The present invention relates to a method for locating an electromagnetic source. It also relates to a system implementing such a method. The invention can be applied in many situations. It can in particular be applied for the elaboration of a tactical situation that is to say for the location of slow or fast fixed or mobile radar transmissions, in terrestrial, maritime or airborne contexts starting from a network of fixed or mobile ESMs on land, sea, drone, aircrafts or helicopters. In particular, the invention applies: In a maritime context, for surveillance from the coast by a network of ESM stations; In a terrestrial context, for example for surveillance by a swarm of drones; In an air context, for example for the trajectory of airborne threats by a network of ESMs embedded in an airplane. The invention particularly relates to the location of a radar emission by using an ESM system composed of one or two remote ESMs performing two types of measurements: On the one hand, an arrival angle measurement AOA (Angle Of Arrival) but preferentially HDOA (Hyperbolic Direction Of Arrival) obtained by TDOA (Time Difference Of Arrival) between two remote ESMs; On the other hand, a measure of Angular Difference of Arrival (ADOA) angular differences between two remote ESMs.
    [0003] In traditional methods, the localization is based on iterative methods by gradient, by the maximum likelihood estimation, requiring calculations of step of the gradient often consuming resources in terms of computational power, or methods requiring to digitize the data. research space.
    [0004] An object of the invention is especially to estimate the location of the emission by a direct calculation and therefore not iterative. To this end, the subject of the invention is a method for locating an electromagnetic emission source 5 from an ESM receiver network, said source emitting a transmission beam scanning the space, said method comprising: a step of calculating a first geometrical shape from a first measurement giving an arrival angle difference information of said emission beam on two receivers, said first geometrical shape comprising the points of the space giving the same first measurement on said two receivers; a step of calculating a second geometric shape from a second measurement giving an arrival direction information on at least one receiver, said second geometric shape comprising the points of the space giving the same second measurement on said receiver; a step of calculating the position of said source, said position being the intersection of said first geometrical shape and said second geometrical shape. In a particular embodiment, said method comprises: a step of measuring arrival angle difference (A0) of said transmission beam on two receivers, called ADOA measurement; a step of calculating a so-called ADOA cylinder from said ADOA measurement, said iso-ADAO cylinder corresponding to points in the space giving the same ADOA measurement for said two receivers; a step of measuring the arrival time difference of said transmission beam on said two receivers, called TDOA measurements; A step of calculating a hyperboloid called iso-AOA from said AOA measurements, said iso-TDOA hyperboloid corresponding to points giving said same TDOA measurements; A step of calculating the position of said source, said position being the intersection of said iso-ADOA cylinder and said iso-TDOA hyperboloid. In another particular embodiment, said method comprises: a step of measuring the difference in time passing said emission beam on two receivers, called DTPL measurement; a step of calculating a cylinder said iso-DTPL from said measurement DTPL, said cylinder iso-DTPL corresponding to points in the space giving the same measurement DTPL for said two receivers; a step of measuring the arrival time difference of said transmission beam on said two receivers, called TDOA measurements; a step of calculating a hyperboloid called iso-AOA from said AOA measurements, said iso-TDOA hyperboloid corresponding to points giving said same TDOA measurements; a step of calculating the position of said source, said position being the intersection of said iso-ADOA cylinder and said iso-TDOA hyperboloid. The calculation of said cylinder is for example carried out in two dimensions, corresponding to a given altitude, corresponding to the calculation of a circle, the position of said source being the intersection of said circle and said iso-TDOA hyperbola. ESM sensors are for example worn by an aircraft. Said network comprises for example a single ESM sensor, the measurements 25 being made in two consecutive positions of said sensor. Said source being mobile, the step of calculating the position of said source at a given instant is for example followed by a Kalman filtering step and prediction of the positions of said moving target.
    [0005] The invention also relates to a system for locating an electromagnetic emission source comprising at least one network of ESM sensors and processing means implementing said method.
    [0006] Other features and advantages of the invention will become apparent from the description which follows, given with reference to the appended drawings which represent: FIGS. 1a and 1b, an illustration of contexts of application of the invention ; FIG. 2, an illustration of the type of measurements used; FIG. 3, an illustration of a measurement of the DTPL type, measure of time difference of transmission lobes; Figure 4 is a representation of a scanning radar lobe intercepted by two ESM receivers; Figure 5 is a representation of the positions of a target and two ESM receivers in an orthogonal coordinate system; Figures 6a and 6b, an example of geometric shape used in the implementation of the invention, a cylinder in this example; FIG. 7, an example of a change of reference allowing the calculation of a second geometrical shape used in the method according to the invention. Figures 1a and 1b illustrate contexts of application of the invention. FIG. 1a shows a target 1 producing a transmission 10. In the example of FIG. 1a, the target 1 is a rotary radar. Two ESMs are embedded on two mobile carriers 11, 12, each carrier being equipped with an ESM. FIG. 1b illustrates the same configuration but with two fixed ESMs 13, 14. The invention deals with the location of a fixed transmission by two fixed or mobile ESM stations. However, it can be applied to a single ESM station in motion.
    [0007] The invention can also be applied to a mobile emission, slow or fast, insofar as the estimation being carried out on a lobe passage, the successive positions can then be filtered by many conventional methods, including a Kalman filter. . A sequence of integrated positions is then obtained by the filtering with reconstitution of the target speed.
    [0008] Figure 2 illustrates the two types of measurements used. Two types of measurements are considered: the Angular Difference Of Arrival measurement (ADOA) measuring the arrival angle difference Aa of the radar emission on two remote ESM receivers 21, 22; - DOA (Direction Of Arrival) type measurement, giving a direction of arrival. The two ESMs 21, 22 can subsequently be called ESM1 and ESM2 respectively. The measurement of the ADOA type can in particular be carried out by the following different methods: The measurement of DTPL (Lobes Passage Time Difference) for radar with constant scanning speed w on the passage between the two ESMs; - The difference of two angular measurements (sufficiently precise) on each ESM, between the two ESMs; - The measurement of angular variations of LBPDE (Long Baseline Phase Difference Evolution) type on a single plane in motion using a large interferometric base; The arrival Doppler frequency measurement known as FDOA (Frequency Doppler Of Arrival) performed on a single moving ESM or between two ESMs.
    [0009] The DOA measurement may in particular be carried out by the following different methods: AOA measurement obtained on a single aircraft by a goniometer device measuring amplitude, phase or TDOA short base; 30 - The TDOA measurement (Time Difference Of Arrival) measuring the arrival time difference of the radar pulses on two remote ESM receivers 21, 22 corresponding to two carrier aircraft.
    [0010] These two measurements, although not responding to the same equations, give the first-order equivalent to a DOA measurement, the TDOA measurement being a priori more accurate than the AOA-type measurement.
    [0011] For certain measurement combinations envisaged, the method applies to particular type of radar transmissions. For example, the DTPL measurement applies to constant-scan radars. The measurement of the single-receiver ESM FDOA applies to coherent waveforms.
    [0012] The invention will be described in the following particular context: The ADOA measurement results from the measurement DTPL (lobe passing time difference) and the measurement or knowledge of the scanning speed w of the supposedly constant radar emission. during the transition between the remote ESMs. The measurement of DTPL can be obtained by considering the difference of the TPL (lobe passing time) of the same lobe on the two ESMs; The TDOA measurement results from the difference in the arrival times of the radar emission on the two remote ESMs.
    [0013] Figure 3 illustrates the measurement of DTPL. This Lobes Passage Time Difference measurement is the difference in transit time T from the emission of a radar that sweeps at speed w on two fixed stations. The example of Figure 3 is given without loss of generalities and the same equations apply to the first order even for fast mobiles. The following situation is assumed: A radar 1 emits sweeping space at a rotational speed w assumed to be fixed and known; The passage of the main lobe 31 is observed on two ESM stations 21, 22. The time of passage of the main lobe is t1 on the first, ESM1, and t2 on the second, ESM2; The difference in lobe passing time (DTPL) is given by ATI2 in the following equation: AT12 = t1-l2 = Da + r1 -r2 + n12 (1) where Aa is the angle difference of arrival Aa of the radar emission on the two remote receivers 21, 22, r1 and r2 being the respective distances of these two receivers to the radar, n12 is a supposed Gaussian noise of standard deviation of 1 to 5 ms. The lobe passage date can be obtained with this precision by integration - on successive lobes. The measurement of the arrival time difference between the two remote observers 21, 22 is also considered. The measurement techniques used in radar and EW have notably been described in the article by Quazi, AH. IEEE ASSP-29, No. 3, June 1981, pages 527-533. The technique used consisting in the search for the peak of the intercorrelation function is also presented in the article by Piersol, AG "Time delay Estimation Using Phase Data", IEEE ASSP-29, No. 3, June 1981, pages 471 -477. There are several other competing techniques including a technique using the Fourier transform phase of the intercorrelation function. TDOA = ri - r2 The TDOA (Time Difference Of Arrival) corresponds to the time difference 20 during the course of r1 and r2 by the radar waves. Since the order of magnitude of c is 3.108 m / s, which corresponds to a distance traveled of 300 km in 1ms, the term - r2 is negligible c before n12 in equation (1) of the DTPL, because n12 is about 1 ms and the distance between the stations 21, 22 is of the order of 3 km. The term ri r2 may therefore be neglected in the resolution. Finally, in the first order, the difference in the passage time of the lobe is: AT = Aa (2) co. Thus, two measurements are given by the following equations: 3037659 8 Measurement of the arrival time difference TDOA: TDOA = rl-r2 c Measurement of the difference in lobe passing time DTF'L: Aa = (DAT 5 The localization is obtained by finding the values of the position of the emission which satisfy these two equations simultaneously. "ESM Lobe" is a set of pulses resulting from a so-called "deinterlacing" operation performed in parallel on each ESM which consists in seeking to group together all the pulses coming from the same radar and corresponding to a lobe passage. From the pulses of each lobe, for each ESM station 21, 22: 15 a quadruplet of measurements VOAk, TPLk, LLAk, Niva summarizing the geometric parameters of the lobe, assuming otherwise known the precise position of the lobe, is calculated. ESM 21, 22; A radio description of the perceived waveform (List of PRIs, frequencies and Dl mainly).
    [0014] These lobes are then tracked locally on each ESM by a method using: The similarities between the radio descriptors; - The proximity of TDOAs; 25 The regularity of the dates of passage of the TPL lobes. The present invention relates neither to the deinterlacing function, nor to the function of characterizing the lobes, nor to the function of association of the lobes in a single platform, nor to the function of identifying the emission.
    [0015] These operations are known and assumed to be performed elsewhere. Without loss of generality the elemental localization provided on a lobe passage may be integrated by any tracking of the transmission lobe sequences over time.
    [0016] FIG. 4 represents the lobe 41 of the radar 1 scanned intercepted by the two ESMs, ESM1 and ESM2. These two ESMs intercept the same ImpX pulses but with different levels, related to the radar illumination function and with a TDOA related time offset. In the general case, the temporal sequence of the pulse pattern is independent of the temporal evolution of the radar lobe. This amounts to independence between the DTPL and TDOA measures. In this application, the locating method accomplishes the following steps: For each ESM i. o For each intercepted lobe k, compute a quadruplet of measurements (TOAk, TPLk, LLk, Nivic), summarizing the geometrical parameters of the lobe 41, this lobe being also characterized by a summary of the characteristics of the FO (PRIs, 15 Frequencies , Dl, intra-pulse codes ...). - For each pair of ESM stations: o Association of lobes of the same program between the platforms; o Estimation of the radar scan 1 or antenna rotation period (ARP) co-speed of the radar 1 by joint estimation, or thanks to the knowledge of the rotation period (PRA) thanks to the ESM identification ; o Calculation of the resulting DTPL circle; o TDOA estimation by integrating the TDOAs of the pulses 25 received on the 2 ESMs, this integration being able to be carried out by different methods including the correlation of the pulse trains received by the two receivers or the simple average of the arrival time differences ( TOA) impulses received by the 2 ESMs; O Calculation of the resulting TDOA hyperboloid. For all ESM stations: o Calculation of the intersection location of DTPL circles and TDOA hyperbolas; o If two stations are used, calculate the intersection of the DTPL circle 5 and the TDOA hyperbola. It is at this level of location processing, for all ESM stations, that the invention comes into play.
    [0017] The determination of the location according to the invention is described only in the context of TDOA and DTPL measurements, but the invention is also applicable to all the systems described above. These systems all perform localization based on a measurement of angular type or direction (here the TDOA) and a measurement of angular difference type (here the DTPL).
    [0018] FIG. 5 shows the target 1 and the two ESM receivers 21, 22 in a reference frame O, x, y, z at the time of an ith measurement, i being between 1 and N. Indeed, two observers 21, 22 perform N TDOA measurements (difference in time of arrival of the same signal between the two remote sensors 21, 22) and DTPL (lobe passing time difference) on the fixed target 1. Note ti the measure of TDOA and DTPL measurement between the first receiver 21 and the second receiver 22. Note also Rtiet Rzi the respective distances of the first and second receiver to the target. In the reference numeral 51, the coordinates of the target, the first receiver and the second receiver at the ith measurement are respectively: (xe, ye, Ze), (x1,1, yi, i, z1,1), (( 2, i, Y2,1, Z2,1) The DTPL measurements respond to the following explicit measurement equations: ## EQU1 ## where ## EQU1 ## The TDOA measurements respond to the following explicit measurement equations: ## EQU1 ## The values of TDOA correspond to the following explicit measurement equations: ## EQU2 ## 2 (Xe - X2,1) (Ye Y2, i) 2 + (ze) 2 Z2,1, - (Xe - X1,1) lYe + lze zi, i) C 5 the Theorem of the inscribed angle, the points giving the same measurement of DTPL for positions of the given receivers are located on a cylinder 61 called the iso-DTPL circle illustrated in Figure 6. This cylinder contains the positions P1, P2 of the receivers 21 , 22 and the position Pe of the target 1.
    [0019] Where C is the center of the base circle 62 of the cylinder, according to the centric angle theorem, the angle P1CP2 is twice the angle AO obtained from the measured DTPL between the receivers 21, 22 where AO = PRA x DTPL. In addition, by definition of the radius R of the circle, there is equal distance between C and P1 and between C and P2, that is to say that C is on the mediator of the segment [PiP21, denoted med [PiP2]. We thus obtain the following system, noting M the middle of the segment [Pi-T] 21: C {CE medffl P1CP2 = 2 AO Im-E, = k (Yi-Y2) X2 - Xi / d12 kx d12 = 2 tan AO <=> MC = tan AO {Ke> = k (Y1 - Y2) bel <=> {Y1 - Y2 2 tan A @ 4 #> Xc = Xm + We deduce the radius R from the base circle 62 of the cylinder iso-DTPL, where r12 is the distance between the positions P1 and P2 in the x, y plane: x2 - xi / (xi - x2) 2 + (Yi - Y2) 2 Isin001 = 2Isin A01 - 2IsinA01 X2 - x1 ' Yc = Ym + 2 tan AO R = M P1 r12 3037659 12 Finally we obtained the equation of the cylinder iso-DTPL: - xc) 2 + - yc) 2 = R2 With Ixc = 2 2 tan Ae Yi + Y2 X2 - X1 Yc = 2 + 2 tan Ae R =, / (x1, / (x1-x2) 2 + (Yi-Y2) 2 2 'sin MI + X2 Y2 - Y1 The points giving the same TDOA measurement for positions of given receptors are located on a hyperboloid called hyperboloid isoTDOA, which is obtained by the calculations presented hereinafter from the representation of FIG. 7. The position Pe of the target 1 and the positions P1, P2 of the recess 21, 22 are calculated in a new orthogonal reference frame O ', x', y ', z' where O 'is equal to P1 and where the x' axis passes through P1 and P2. In this reference, the position Pe is indicated by the coordinates (x'e, Ye, e). We denote by R1, R2 the respective distances of the first and second receivers 21, 22 to the target, and we denote by d12 the distance between these two receivers.
    [0020] Noting ci) the angle between the axis x 'and the projection of Pi Pe in the plane x', y 'and noting 0 the angle between the axis z' and Pi Pe, it comes: - x Moreover, R2 = R1 + c.t12 where t12 is the difference in arrival time between the receivers 21 and 22. According to FIG. the Pythagorean Theorem: R 2 2 = (C112 - Xe 1) 2 + (Ye 12 Ze 12) Let (R1 + c t12) 2 = (d12 - R1 sin 0 cos (p) 2 + (R1 sin 0 sin (p) 2 + (R1 cos 0) 2 3037659 13 We deduce the polar equation of the iso-TDOA hyperboloid: d122 - e2 t122 R1 (° 1 (P) = = 2 (c t12 + d12 sin 0 cos (p) 1 + e sin 0 cos (p noting p = d122 -c2t122 and e = d12 2 CC 5 We obtain then the equation of the hyperboloid in Cartesian coordinates in the coordinate system (0 ', x', y ' , 2 ') using the formulas fx' = Ri sin 0 cos (p sin 0 cos (p = 1 y '= Ri sin 0 sin 9, let z' = Ri cos 0 R1 = ix'2 + y'2 + z'2 After calculations, we get the equation: 10 by noting (3ct c112) 2 2 Y12 z12 = 1 a2 b2 b2 pd 122 - C2 t122 C2 t122 CX e2 - 1 2 c t12 d122 - C2 t122 2 d122 C2 t122 X - 1 2 c ti2 d12 X -22) y / 2 - ie C t12. D122 - c2 t122. 1d122 - c2 t122 2 z, 2 1 = 4. C2 t122 d122 - C2 t122 d122 - C2 t122 For the continuation, it is necessary to express the formulas of passage of the reference (0, x, y, z) with the mark (0 ', xi, y ', 2') (and vice versa). After calculations, it comes: I X2 - X1 Y2 - Y1, Z2 - Zi X '= (X X1) + 3 /. Yi) + d12 (Z Zi) d12 d12 u12 Y1 -Y2 X2 -X1 Y '= (x x1) + (Y-Yi) r12 r12 (x2-x1) (z2-z1) (Y2-Y1) (z2-y1) z1),, ri2, z '= (x x1) ly - 3,1) + -A z - Z1) d12 r12 d12 r12 `-112 And conversely X = X + x2 - 3C1 X, Y2 - Y1, (X2 - Xi) (Z2 - Zi), i d12 Y u12 r12 d12 r12 Z = Y1 + XI + Y Y2 - Y1 X2 - X1, (Y2 - Y1) (Z2 - Z1) z,, I t112 r12 d12 rice Z2 - Zi, 1-12, = zi +, x + - AZ U12 U12 Noting rice {di2 = .N / (xi - x2) 2 + (Yi - Y2) 2 = .N / (xi - x2) 2 + (Yi - Y2) 2 + (z1 - z2) 2 In order to simplify the expression of the intersections, the equations of the iso-DTPL cylinder and of the iso-TDOA hyperboloid are written in the frame (0 ', x', y ', z') previously defined. The following system is obtained after calculation: 1-12 x, z2 - z1 r12) 2 C2 t122 d12 Zi dy 2 2 tarin2A0) (x, - 2 == R2 (di2, 2 ± (y 'z'2 1 {12 2) 4122 - c 2 422 4122 - C2 F (-122 4 In order to simplify the resolution, we try to determine the intersection between the iso-DTPL cylinder and the iso-TDOA hyperboloid in the constant z plane, which is returns from the reference change formulas, noting 10 C = z - zi, to have: Z2 Z1-ru rx - z = 'd12 d12 (S) 3037659 The intersection of these three geometries is now calculated. We thus obtain the system consisting of the three preceding equations, namely: e Z = c112 C Z2 Z1 x, r12 r12 2 (r12, z2 - zi. (Z2 - Z1) 2, r12 r12 2 AXC + + (y 'U12 r12 r12d12 x 2 2 tan De) = R2 - (X 'd12) Y 2, 2 d12 c Z2 - Z1 x') 2 rice r12 1 = 4 Z = L r12 2 d12 Z2 - Z1 x, 2 tan AO = R2 r12 r12 2 d12X Z2 - Z1 112 + <=> - r12 r12 2 YY - x - d12) 2 d c2t122 (d12 c Z2 - Z1 3c,) 2 12 d 2 = (- 0 422) 2 c2t122 r12 5 Subtracting the third equa to the second, we get: r12 (2.7, r12 ± (c112 x, z2 - z1 r1212 + (x, _A, 412) 2 2 tan Ae Y 2 tan Lie) r12 r12 C 2 2 CX 4122 - C2t122 (d12 Z2 - Z1 3 (,) 2 = R2 + ..... c2t122 r12 1-12 4 1 (d122 - c2t122) => y = a1 x + a2 x + a3 With: {.tan AO x d122 a1 = r12 c2t122 tan Ae (d123 a2 = X212 C2t122) 0122 - c2t122) 2 a3 = tan Ae x C2 + C (z2 Z1) + - r12 4c2t122 2t d122, 21_Ca 122 A '112 - a, The previous system then becomes: 2 Crur Z2 - Z1 c r12) r12 + (ai x'2 + a2 + a3 2 ru r12 2 2 tan Ae) = R2 Z1 = d12 C x Z2 - Z1, {- r12 r12 y = a1 x, 2 + a2 x '+ a3 Let: 5 b1 x'4 + b2 x'3 + b3 x'2 + b4 x' + b5 = 0 y '= ai x ^ 2 + a2 x + a3 Z, = d12 L, Z2 - Z1. x, r12 r12 with bu = ai 2 b2 = 2 aia2 r12 1 r12 2 b3 = c112) 2ai 2 tan Aed a22 + (a3 ri2 C12) b4 = d12 (Z2-Z1) C a3 (2 rice r12 + 2a2 ( a3 2 tan te) - R2 (Z2 - r12) r12 2 b = 2 5 r12 2 2 tan Ae) To solve this system, it suffices to solve by known methods a polynomial equation of degree 4 in x, of the form ax4 + bx3 + cx2 + dx + e = 0. Up to degree 4, several known explicit resolution methods can be used. On the other hand, it is shown that from the 5th degree no explicit method of resolution exists.
    [0021] At this stage according to the invention, a location obtained by direct explicit calculation of the intersection of the cylinder lso-DTPL and the hyperboloid TDOA in the plane of altitude 0, corresponding to the plane O, x, is therefore available. y, 3037659 17 for a chosen point for example 100 km in the direction of the radar emission 1 on the bisecting plane of the base formed by the two ESMs. Advantageously, the method according to the invention forms, from the measurements, a polynomial equation of degree 4 which is then solved by using methods of explicit resolution of this type of equation. Several known methods of resolution can be used, among them we can mention the resolution of a degree equation of 4 by the method of Ferrari or the resolution of an equation of degree 4 by the method of Lagrange. According to the invention, the product resolution algorithm is therefore an explicit algorithm and does not use conventional gradient resolutions, for example MLE (Maximum Likehood Estimation) algorithms, also called EMV (Maximum Likelihood Estimation). . In the explicit methods, it is sought to geometrically construct the solutions as intersections of certain curves or surfaces, for example the iso-DTPL cylinder, the hyperboloid TDOA or the altitude plane 0 in the case of the invention. The solution is then obtained without iteration and without having to evaluate it on multiple positions, hypothesis of a digitized search space. Not only is there a very large gain in computing power resources, but in addition: an execution time can be calculated as a function of the number of input data; in the same way the memory occupation is predictable; there is no risk of divergence since the method uses a direct and non-iterative calculation. The method according to the invention is therefore suitable for real-time execution. Indeed, it uses a memory size and requires a calculation time both of which are predictable. It applies advantageously to many types of ESM measurements.
    [0022] Advantageously, the altitude error, in Z, has no influence on the iso-DTPL cylinder. It may then be advantageous to eliminate the variable Z in the resolution by setting the value of the altitude to avoid artificial indeterminacy in the system of equations. Indeed, since the altitude error has a small influence, it may be preferable not to try to estimate it to avoid this artificial indeterminacy. If one wishes to obtain a greater precision, after a calculation of localization estimating a first localization, one specifies the altitude with this point of localization using the numerical model of the ground at disposal. The process is then repeated from this altitude using the same explicit resolution according to the invention. The measurement qualities envisaged for the DTPL type (precision of 1 ms) and for the TDOA type (precision of 10 ns) already give an accurate location in mono-measurement. In the context of a fixed or mobile target, quasi-instantaneous measurements of two-to-two intersection of a number P of distant ESMs lead to P (P-1) / 2 intersections. A barycenter estimator of the exact intersections is then produced. This estimator is biased because there are only P couples of independent measurements but in the 15 cases DTPL, TDOA the measurements are so precise that this bias is negligible. It is always possible to use the estimate obtained to initialize an asymptotically unbiased method that converges without difficulty because initialized very close to the real solution. In the case of a fixed target, and fixed ESMs, the measurements of DTPL 20 and TDOA are constants and can therefore be integrated, leading to even more accurate performance. In the context of a moving target, the instantaneous locations obtained can be processed by Kalman filtering to estimate the evolution of the target. From a position calculation at a given time, it is thus possible to predict the positions of the target over time. The invention has been described for DTPL type measurements, measuring differences in the transmission beam time of the source, and for TDOA type measurements, giving differences in the arrival time of the beam of the beam. transmission, the transmission beam being intercepted on two remote ESMs fixed or mobile. Other types of measurements giving information on the angle of arrival difference and the direction of arrival of the emission beam can be used, all these measurements making it possible to geometrically construct the solution according to the invention as an intersection. certain geometric shapes obtained from these measurements. These geometric shapes are sets of space points that would give the same measure if the source was arranged at these points. It is thus possible to construct iso-ADOA curves corresponding to points in the space giving the same ADOA measurement for two receivers 21, 22, or even altitude planes O. The ADOA measurement and the DOA measurement can be made from different ways as previously indicated.
    [0023] A system implementing the method according to the invention comprises at least one network of ESM sensors performing the various measurements and processing means for determining the location of an electromagnetic emission source from these measurements. The description has been made for a system comprising a network of two sensors.
    [0024] It is possible to make a system reduced to a single ESM sensor. In this case: the measurement of ADOA type considered is an integrated differential measurement during the evolution in the space of the carrier of the single ESM sensor, between two consecutive measurement positions, for example taking into account the difference in phase measured on a large interferometric base or LBPDE, FDOA or DTPL; the measurement of AOA can be a conventional angular measurement, obtained for example by an interferometric device. 25
    权利要求:
    Claims (8)
    [0001]
    REVENDICATIONS1. A method of locating an electromagnetic emission source (1) from an array of ESM receivers (21, 22), said source (1) emitting a scanning beam (10) scanning the space, characterized in what it comprises: a step of calculating a first geometrical shape (62) from a first measurement giving an arrival angle difference information of said emission beam on two receivers (21, 22) said first geometric shape having the points of the gap giving the same first measurement on said two receivers (21, 22); a step of calculating a second geometric shape from a second measurement giving arrival direction information on at least one receiver (21, 22), said second geometric shape comprising the points of the space giving the same second measurement on said receiver (21,22); a step of calculating the position of said source, said position being the intersection of said first geometrical shape and said second geometrical shape.
    [0002]
    2. A method of locating an electromagnetic emission source (1) according to claim 1, characterized in that it comprises: an angle of arrival difference measuring step (A8) of said transmission beam on two receivers (21, 22), called ADOA measurement; a step of calculating a cylinder (62) said iso-ADOA from said ADOA measurement, said iso-ADAO cylinder corresponding to points in the space giving the same ADOA measurement for said two receivers (21, 22); a step of measuring the arrival time difference of said transmission beam on said two receivers (21, 22), called TDOA measurements; a step of calculating a hyperboloid said iso-AOA from said AOA measurements, said iso-TDOA hyperboloid corresponding to points giving said same TDOA measurements; A step of calculating the position of said source, said position being the intersection of said iso-ADOA cylinder and said iso-TDOA hyperboloid. 5
    [0003]
    3. A method for locating an electromagnetic emission source (1) according to claim 1, characterized in that it comprises: a step of measuring the time difference passing said emission beam on two receivers (21, 22 ), called DTPL measurement; a step of calculating a cylinder (62) said iso-DTPL from said measurement DTPL, said iso-DTPL cylinder corresponding to points of the space giving the same measurement DTPL for said two receivers (21, 22) ; a step of measuring the arrival time difference of said transmission beam on said two receivers (21, 22), called TDOA measurements; A step of calculating an iso-AOA hyperboloid from said AOA measurements, said iso-TDOA hyperboloid corresponding to points giving said same TDOA measurements; a step of calculating the position of said source, said position being the intersection of said iso-ADOA cylinder and said iso-TDOA hyperboloid.
    [0004]
    4. A method of locating an electromagnetic emission source (1) according to any one of claims 2 or 3, characterized in that the calculation of said cylinder (62) is performed in two dimensions, corresponding to a given altitude , corresponding to the calculation of a circle (61), the position of said source being the intersection of said circle (61) and said iso-TDOA hyperbola.
    [0005]
    5. A method of locating an electromagnetic emission source (1) according to any one of the preceding claims, characterized in that the ESM sensors (21, 22) are carried by an aircraft. 3037659 22
    [0006]
    6. A method of locating an electromagnetic emission source (1) according to any one of the preceding claims, characterized in that said network comprises a single ESM sensor, the measurements being performed in two consecutive positions of said sensor. 5
    [0007]
    7. A method of locating an electromagnetic emission source (1) according to any one of the preceding claims, characterized in that said source (1) being mobile, the step of calculating the position of said source to a given instant is followed by a Kalman filtering step and prediction of the positions of said moving target.
    [0008]
    8. A system for locating an electromagnetic emission source (1), characterized in that it comprises at least one network of ESM sensors and processing means implementing the method according to any one of the preceding claims. .
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    同族专利:
    公开号 | 公开日
    FR3037659B1|2020-01-03|
    WO2016202748A1|2016-12-22|
    EP3311185A1|2018-04-25|
    US20180149729A1|2018-05-31|
    US10852388B2|2020-12-01|
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    优先权:
    申请号 | 申请日 | 专利标题
    FR1501253A|FR3037659B1|2015-06-17|2015-06-17|METHOD FOR LOCATING AN ELECTROMAGNETIC TRANSMISSION SOURCE AND SYSTEM IMPLEMENTING SUCH A METHOD|
    FR1501253|2015-06-17|FR1501253A| FR3037659B1|2015-06-17|2015-06-17|METHOD FOR LOCATING AN ELECTROMAGNETIC TRANSMISSION SOURCE AND SYSTEM IMPLEMENTING SUCH A METHOD|
    PCT/EP2016/063521| WO2016202748A1|2015-06-17|2016-06-13|Method and device for locating an electromagnetic emission source and system implementing such a method|
    EP16728700.2A| EP3311185A1|2015-06-17|2016-06-13|Method and device for locating an electromagnetic emission source and system implementing such a method|
    US15/577,295| US10852388B2|2015-06-17|2016-06-13|Method and device for locating an electromagnetic emission source and system implementing such a method|
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