A distributed multi-source circular array reverse cross-eye jamming configuration design and evaluation method

Abstract

The present application relates to a kind of distributed multi-source circular array reverse cross eye jamming configuration design and evaluation method, belong to radar jamming field.The present application is aimed at the problem that the interference performance of general configuration distributed multi-source reverse cross eye jamming G-DMRCJ is unstable due to larger jamming loop difference, the present application proposes a new type of distributed multi-source circular array reverse cross eye jamming (C-DMRCJ, Circularly Distributed Multiple-Element Retrodirective Cross-Eye Jamming) configuration, respectively establishes the jamming performance evaluation model of C-DMRCJ to single pulse radar under isolated platform reflection echo and considering platform echo scene, obtains the single pulse ratio, total cross eye gain and single pulse indication angle of C-DMRCJ under isolated platform reflection echo and considering platform echo scene;The jamming loop difference calculation model caused by configuration of C-DMRCJ is built, and the jamming loop difference caused by distributed positioning error is obtained.Numerical simulation shows that: the jamming performance of the C-DMRCJ of the present application is equivalent to that of G-DMRCJ, but C-DMRCJ can effectively control jamming loop difference, compared with G-DMRCJ, more stable jamming performance can be obtained.

Description

Technical Field

[0001] This invention belongs to the field of radar jamming, specifically relating to a design and evaluation method for a distributed multi-source circular array reverse cross-eye jamming configuration. Background Technology

[0002] Monopulse radar can obtain target angle information through a single pulse echo. It is a precise angle measurement technology with strong anti-jamming capabilities and is widely used in various guided weapons, posing a serious threat to modern military systems. Countermeasures against monopulse radar are a research hotspot and challenge in the field of electronic warfare. Angle deception jamming techniques against monopulse radar include towed decoys, cross-polarization jamming, formation jamming, and cross-eye jamming; among these, cross-eye jamming is considered the most effective monopulse radar jamming technique.

[0003] Cross-eye jamming has gone through three development stages: artificial angle flicker, two-element retrodirective cross-eye jamming (TRCJ), and multiple-element retrodirective cross-eye jamming (MRCJ). MRCJ can be further divided into centralized and distributed types based on whether the jamming loops share the same phase center. Since 2009, theoretical research on centralized TRCJ and MRCJ has become increasingly mature. The literature “du Plessis WP, Odendaal JW, Joubert J. Extended analysis of retrodirective cross-eye jamming[J].IEEE Transactions on Antennas and Propagation, 2009, 57(9):2803-2806” has conducted an in-depth study on the jamming mechanism of centralized TRCJ and is a fundamental research result in the field of cross-eye jamming. Based on this, other literature has proposed centralized MRCJ jamming configurations based on multi-source linear arrays and circular arrays, orthogonal four-point sources, and rectangular arrays and analyzed their jamming mechanisms. The above research shows that centralized MRCJ solves the practical limitation of centralized TRCJ by increasing the system's degrees of freedom; however, the following two problems still exist: (1) In practical applications, large application platforms often cannot meet the installation requirements of centralized MRCJ configurations; (2) The excessively long jamming baseline causes the platform's reflected echo to separate from the jamming echo, which is easily eliminated by radar.

[0004] Distributed MRCJ (DMRCJ) can achieve good jamming performance with a shorter baseline in irregular spatial configurations, and the jammers can be flexibly deployed in a distributed manner, solving the problem of difficult configuration implementation of centralized MRCJ on large application platforms. Furthermore, DMRCJ has the characteristics of being off-platform and capable of self-destruction, meaning that once the jammer is identified as a beacon machine, it can self-destruct. It represents the cutting-edge research area and development trend in the field of cross-eye jamming. It is estimated that the US military's "Advanced Outboard Electronic Warfare" project is very likely to have adopted the DMRCJ system, which involves detecting incoming missiles and determining their direction through offboard airborne electronic pods, sharing information with ships to achieve ship-aircraft coordinated electronic warfare, and using its own electronic attack system to emit jamming signals to deflect missiles away from the ship.

[0005] However, there is relatively little theoretical research on DMRCJ. Only duPlessis WP's literature analyzes the interference mechanism and interference loop difference of distributed linear two-loop reverse cross-eye, but its theoretical derivation still assumes the existence of a virtual phase center, thus essentially remaining a centralized MRCJ system on a single platform. Moreover, the generally distributed MRCJ (G-DMRCJ) has a large interference loop difference. Therefore, this invention proposes a distributed multi-source circular array reverse cross-eye interference configuration (C-DMRCJ), derives the single-pulse ratio and single-pulse indication angle of C-DMRCJ in isolated platform reflected echo and considering platform echo scenarios, and analyzes the magnitude of the interference loop difference caused by distributed positioning errors. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] The technical problem to be solved by this invention is how to provide a design and evaluation method for a distributed multi-source circular array reverse cross-eye interference configuration, so as to solve the problem of unstable interference performance of the general configuration of distributed multi-source reverse cross-eye interference G-DMRCJ due to large interference loop differences.

[0008] (II) Technical Solution

[0009] To address the aforementioned technical problems, this invention proposes a design and evaluation method for a distributed multi-source circular array reverse cross-eye interference configuration. This method includes: establishing an evaluation model for the interference performance of distributed multi-source circular array reverse cross-eye interference (C-DMRCJ) on monopulse radar under isolated platform reflected echo and platform-considered echo scenarios; obtaining the monopulse ratio, total cross-eye gain, and monopulse indication angle of C-DMRCJ under isolated platform reflected echo and platform-considered echo scenarios; and constructing a calculation model for the interference loop difference caused by the configuration of C-DMRCJ to obtain the interference loop difference caused by distributed positioning errors.

[0010] (III) Beneficial Effects

[0011] This invention proposes a design and evaluation method for a distributed multi-source circular array retrodirective cross-eye jamming configuration. Addressing the issue of unstable jamming performance in general distributed multi-source retrodirective cross-eye jamming (G-DMRCJ) due to large interference loop differences, this invention proposes a novel distributed multi-source circular array retrodirective cross-eye jamming (C-DMRCJ) configuration. Evaluation models for C-DMRCJ's jamming performance against monopulse radar are established for scenarios with isolated platform echoes and scenarios considering platform echoes, along with a model for calculating the interference loop difference. Numerical simulations show that the C-DMRCJ of this invention has comparable jamming performance to G-DMRCJ, but C-DMRCJ can effectively control the interference loop difference, achieving more stable jamming performance compared to G-DMRCJ. Attached Figure Description

[0012] Figure 1 This invention's C-DMRCJ configuration is designed to withstand interference scenarios from phase-comparison monopulse radar.

[0013] Figure 2 The diagram shows the C-DMRCJ interference error analysis.

[0014] Figure 3 A schematic diagram of C-DMRCJ interference loop difference analysis considering distributed positioning errors;

[0015] Figure 4 Comparison curves of the single-pulse indication angles of C-DMRCJ and G-DMRCJ;

[0016] Figure 5 Comparison curves of the single-pulse indication angle of C-DMRCJ under different interference loop phase differences;

[0017] Figure 6 (a) shows the curve of phase difference of the interference loop as a function of interference distance. (b) shows the curve of phase difference of the interference loop as a function of interference distance (ΔR). n2 =5m); (b) is the curve of the phase difference of the interference loop as a function of the interference distance (ΔR) n1 =100m). Detailed Implementation

[0018] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0019] This invention establishes an evaluation model for the interference performance of C-DMRCJ against monopulse radar under isolated platform reflected echo and platform-considered echo scenarios, obtains the monopulse ratio, total cross-eye gain, and monopulse indication angle of C-DMRCJ under isolated platform reflected echo and platform-considered echo scenarios; constructs a calculation model for the interference loop difference caused by the configuration of C-DMRCJ, and obtains the interference loop difference caused by distributed positioning errors.

[0020] Figure 1 This is a schematic diagram of the C-DMRCJ configuration designed in this invention to counter a phase-comparison monopulse radar. The protected platform target is represented by a black square. Distributed cross-eye jammers outside the platform perform distributed positioning of the monopulse radar, and the C-DMRCJ is formed with the monopulse radar as the center. The monopulse radar is located at the origin, and its aperture spacing is d. p The distance from its center to the center of each interference loop is r, and the angle of its line of sight relative to the protected platform target is θ. r The angle of rotation of its line of sight relative to the center direction of the interference loop n is θ. rn =θ r ±arcsin(d ln / r); The C-DMRCJ consists of 2N antenna elements and N interference loops. Antenna element n and antenna element 2N-n+1 form interference loop n, with a baseline length of d. cn The baseline length is consistent with the feed line length. Each jamming loop is distributed around the protected platform target according to a given strategy. This invention assumes that jamming loop 1 is the outermost jamming loop of the jammer; the rotation angle of jamming loop n relative to the radar center direction is θ. cn The angle subtended by the center of the interference loop n relative to the radar line of sight is θ. hn The distance from the center of the interference loop n to the radar line of sight is d. ln The half-angle θ between the jammer antenna direction and the center direction of the jamming loop n n It can be approximated as θ n ≈d cncos(θ cn ) / 2r.

[0021] 1. Evaluation model of C-DMRCJ's interference performance against monopulse radar under the reflected echo of the isolated platform

[0022] First, the single-pulse ratio and single-pulse indication angle under the reflected echo from the isolation platform are derived. For example... Figure 1 As shown, the angles between the radar line of sight and jammer antenna element n and 2N-n+1 are θ and θ, respectively. rn ±θ n Then the sum and difference channels of the single-pulse radar at θ rn ±θ n The normalized gains in the directions are respectively

[0023]

[0024]

[0025] Incorporating the reverse characteristics of the jammer antenna array and transforming it using basic trigonometric functions, the total echo of the sum and difference channels of a monopulse radar can be expressed as:

[0026]

[0027]

[0028] in, β is the free space phase constant, β=2π / λ, where λ is the wavelength; Indicates the interference loop difference, c n and These represent the amplitude and phase of the interference loop n, respectively; Indicates the system modulation parameters, a n and φ n These represent the system modulation amplitude ratio and phase difference of the interference loop n, respectively; P n =P r (θ rn -θ n )P r (θ rn +θ n )×P c (θ cn -θ n )P c (θ cn +θ n ), P r (θ) represents the beam of a monopulse radar antenna, P c (θ) represents the jammer antenna beam. At this point, the single-pulse ratio of the C-DMRCJ can be expressed as:

[0029]

[0030] When θ is satisfied n <<βd p At that time, 2k cn As it approaches zero, we have cos(2k) cn )≈1; Since the jammer is located in the far field of radiation of the monopulse radar antenna, d cn << r, then θ n If the value is very small, then the gain of the jammer antenna and radar antenna can be approximated as P. r (θ) rn ±θ n )≈P r (θ rn ), P c (θ cn ±θ n )≈P c (θ cn ), Due to θ rn =θ r1 -arcsin(d l1 / r)+arcsin(d ln Therefore, when the jammer is located in the far field of the monopulse radar's radiation, i.e., r >> d, ln When, then θ rn ≈θ r1 And from θ n <<βd p Then there is as well as Considering the above approximation, equation (5) can be simplified to

[0031]

[0032] Among them, G cn The cross-eye gain of C-DMRCJ, i.e.

[0033]

[0034] The second term on the right-hand side of equation (6) represents the angle measurement error introduced by the C-DMRCJ monopulse radar. When the isolation platform reflects the echo, the magnitude of the angle measurement error is mainly related to the cross-eye gain and sin(2k c1 (This is related to) Theoretically, when a1 + a2 + ... + a n =N and φ1=φ2=…θ n When the angle is 180°, the denominator in equation (7) approaches 0. At this time, the cross-eye gain is the largest, which will cause the largest angle measurement error to the monopulse radar.

[0035] The trigonometric relationship between the single pulse ratio and the single pulse indication angle, the single pulse indication angle θ i It can be represented as

[0036]

[0037] As shown in equations (3)-(7), compared to centralized MRCJ, the baseline ratio of the C-DMRCJ interference loop is always 1, which increases the cross-eye gain and improves the interference performance of the jammer; the C-DMRCJ geometric parameter k sn k cn Its adjustable jammer parameters are significantly different from those of the centralized MRCJ, and it can achieve better jamming performance through more adjustable jammer parameters.

[0038] 2. Evaluation model of C-DMRCJ's interference performance against monopulse radar under platform reflected echo.

[0039] Based on the C-DMRCJ performance evaluation model for monopulse radar jamming under the reflected echo from the isolated platform, a mathematical model of the monopulse radar indication angle considering the reflected echo from the platform is further derived. First, mathematical modeling is performed for the echoes from each distributed platform. To uniformly represent the echoes from each distributed jammer platform and the echo from the protected platform, the angle between the line of sight of the monopulse radar and the point target on each distributed platform is set to θ. rw w∈[0,N]; when w=0, θ rw =θ r When w≠0, θ rw =θ rn At this time, the monopulse radar is in direction θ rw The normalized sum and difference channel gains are respectively

[0040]

[0041]

[0042] Among them, P r (θ rw ) represents the monopulse radar beam in direction θ rw The gain on the platform. The sum and difference channel echoes of the target points on each platform can be expressed as follows:

[0043]

[0044]

[0045] Where, when w≠0, σ w That is, σ n , n∈[1,N], σ n Let σ be the characteristic parameter of the radar cross section (RCS) of each distributed jammer platform; when w = 0, let σ0 = σ, then σ represents the RCS of the protected platform.

[0046] Next, we model the monopulse radar indication angle considering the platform reflected echo. When considering the platform reflected echo, the total monopulse ratio is obtained by normalizing the total difference channel echo to the total sum channel echo. Let θ cn =θ c That is, the jammers rotate at equal angles, and The sum and difference channel echoes can be expressed as

[0047]

[0048]

[0049] in, a s a sn and φ s φ sn These represent the amplitude and phase of the reflected echoes from the protected platform and each distributed jamming platform, respectively. A s A sn With σ, σ n Both are parameters representing RCS, the difference lies in A. s and A sn The beam from the interfering antenna is already included, making the calculation of the interference-to-signal ratio (ISR) simpler. Now, considering the total single-pulse ratio under the platform reflected echo, it is...

[0050]

[0051] The total cross-eye gain can be expressed as

[0052]

[0053] Therefore, the crosseye gain G in equation (8) is... cn Replace with total cross-eye gain G t The expression for the single-pulse indicator angle considering the platform's reflected echo can then be obtained. From equation (15), it can be seen that when considering the platform's reflected echo, the angle measurement error is mainly related to the scene's geometric relationship (k...). s1 k c1 ), jammer system parameters (A n C n ) and platform RCS (A s A sn This is related to the fact that, compared to centralized MRCJ, C-DMRCJ adds echoes from each distributed jammer platform to the sum channel echo, while the difference channel echo remains unchanged, thus reducing the overall cross-eye gain and weakening its jamming performance.

[0054] 3 Interference Loop Difference Calculation Model

[0055] First, a calculation model for the interference loop difference caused by the configuration of C-DMRCJ is constructed.

[0056] Figure 2 Let r be the distance model from any jammer antenna in the jamming loop n to the center of the monopulse radar. jn Let be the transmission distance of the interference signal emitted by the interference antenna in interference loop n, r be the distance from the center of interference loop n to the monopulse radar, and d be the distance from the center of interference loop n to the monopulse radar. cn Let θ be the length of the interference baseline of the interference loop n. cn Let θ be the rotation angle between the center direction of the interference loop n and the center direction of the radar. n Let be the half-angle of the interfering antenna relative to the center direction of the interfering loop n. At this point, the signal transmission path length of the interfering loop n can be approximated as:

[0057]

[0058] In C-DMRCJ, since the baseline lengths of all loops are equal, the total interference loop difference between interference loop n and interference loop m can be expressed as:

[0059]

[0060] This interference loop difference causes a phase difference between the interference loops:

[0061]

[0062] The interference loop difference in G-DMRCJ is very large, mainly determined by the difference in interference distance between different interference loops. Theoretically, when the interference distances of different interference loops are equal, the main factor affecting the magnitude of the interference loop difference can be eliminated. Therefore, this invention proposes a C-DMRCJ interference configuration, in which each interference loop forms an interference configuration with a single-pulse radar as the center, which is a special case of G-DMRCJ. In C-DMRCJ, since cos(θ cn ) << r, therefore r tΔ ≈0; further, let θ cn =θ cm It can completely eliminate the interference loop difference caused by the interference configuration, i.e., r tΔ =0, meaning that C-DMRCJ can, to some extent, avoid the need for precise dynamic compensation of large interference loop differences.

[0063] As a special case of G-DMRCJ, the interference mechanism of C-DMRCJ is the same as that of G-DMRCJ, and will not be elaborated here. The subsequent analysis focuses on the magnitude of the interference loop difference caused by distributed positioning errors. To compare with the simulation results of existing studies on TRCJ and centralized MRCJ, the subsequent analysis of the interference loop difference uses a two-loop, four-element C-DMRCJ as the analysis object. Figure 3A schematic diagram illustrating the C-DMRCJ interference loop difference analysis considering distributed positioning errors.

[0064] like Figure 3 As shown, ΔR n1 and ΔR n2 The distributed cross-eye jammer represents the positioning error of a monopulse radar in two orthogonal directions. c1 and r c2 θ represents the distances from the actual centers of interference loop 1 and interference loop 2 to the monopulse radar, respectively. cr1 and θ cr2 Let θ be the rotation angle between the actual centers of interference loop 1 and interference loop 2 relative to the radar center direction, and let θ be the rotation angle between the actual centers of interference loop 1 and interference loop 2 respectively. h1 =θ h θ h2 =θ k .Depend on Figure 3 Geometric relationships allow us to deduce that the above parameters satisfy the following relationship:

[0065]

[0066]

[0067]

[0068]

[0069] Where, θ h =arcsin(d l1 / r), θ k =arcsin(d l2 / r), r cn d represents the actual distance from the center of the interference loop n to the monopulse radar. cn Let θ be the length of the interference baseline of the interference loop n. crn Let n be the actual rotation angle of the center direction of the jamming loop n relative to the radar center direction, where n takes values ​​of 1 and 2. From the derivation process in Section 2.5, the total jamming loop difference between jamming loop 1 and jamming loop 2 is:

[0070]

[0071] As can be seen from equations (20)-(24), the interference loop error of C-DMRCJ mainly depends on the positioning error ΔR of the distributed cross-eye jammer on the monopulse radar in the longitudinal direction. n2 Size.

[0072] 4. Numerical Simulation

[0073] 4.1 Interference Performance Simulation

[0074] To compare with the simulation results of G-DMRCJ, this section uses a two-loop, four-element C-DMRCJ as the analysis object for simulation verification. The simulation parameters are set as follows: the monopulse radar operating frequency is 12GHz, the antenna beamwidth is 10°, the antenna aperture is 2.54λ, the interference range is r = 1km, and it is assumed that the rotation angle of the interference loop n relative to the radar center direction is 30°, and the distances from the center of interference loops 1 and 2 to the radar line of sight are 2m and 3m, respectively.

[0075] Figure 4 This is a comparison curve of the single-pulse indication angle between C-DMRCJ and G-DMRCJ. Figure 4 It can be seen that the interference performance of C-DMRCJ is comparable to that of G-DMRCJ, and the smaller the interference distance, the better the interference performance, which verifies that C-DMRCJ is a special case of G-DMRCJ. Therefore, due to space limitations, the simulation results of other performance of C-DMRCJ will not be shown one by one.

[0076] Figure 5 This demonstrates the effect of the phase difference in the C-DMRCJ interference loop on the single-pulse indication angle; where c1 = 1. c2 = 0 dB. (From...) Figure 5 It can be seen that: (1) When the phase difference of the interference loop is between 0° and 150°, the phase difference of the interference loop has little effect on the interference performance of the cross-eye interference; (2) When the phase difference of the interference loop is between 150° and 180°, the interference performance of C-DMRCJ decreases; (3) When the phase difference of the interference loop approaches 180°, the single pulse indication angle of the single pulse radar line of sight changes drastically. This is because the phase difference of the interference loop causes the echoes of the sum channel of the two interference loops to cancel each other out, the echo of the sum channel approaches 0, the cross-eye gain amplitude increases, but the sign changes, making it difficult to stabilize the false target on one side of the protected platform.

[0077] 4.2 Interference Loop Differential Simulation

[0078] Figure 6 For different positioning errors ΔR n1 and ΔR n2 The curve showing the change in phase difference of the lower interference loop as a function of interference distance. Figure 5 It can be seen that by controlling the interference loop difference of C-DMRCJ within 150°, good interference performance can be obtained. Figure 6 (a) It can be seen that the compensation error of the phase difference of the interference loop is related to ΔR. n1 Insensitive. By Figure 6 (b) It can be seen that: (1) When the interference distance is constant, the phase difference of the interference loop changes with ΔR n2 The decrease is due to the decrease of ΔR; n1 ΔR n2When the interference loop phase difference decreases as the interference distance increases; (2) when ΔR n2 For distances of 5, 4, 3, and 2 meters, the distributed jammer can control the phase difference of the C-DMRCJ's interference loop within 150° when the distance to the monopulse radar is greater than 4690, 3727, 2762.5, and 1792.9 meters, respectively. This means that as long as the positioning error percentage in the vertical axis direction is less than or equal to 0.1066%, the phase difference of the interference loop is sufficiently small to achieve an infinitely large cross-eye gain median, thus meeting the requirements for the interference loop difference. Here, the positioning error percentage is the percentage of the positioning error relative to the minimum interference distance under this condition.

[0079] This invention addresses the problem of unstable interference performance in generally distributed multiple-element retrodirective cross-eye jamming (G-DMRCJ) due to large interference loop differences. To address this issue, a novel distributed multiple-element retrodirective cross-eye jamming (C-DMRCJ) configuration is proposed. Performance evaluation models for C-DMRCJ against monopulse radar are established for scenarios with isolated platform echoes and scenarios considering platform echoes, along with a model for calculating interference loop differences. Numerical simulations show that the proposed C-DMRCJ has comparable interference performance to G-DMRCJ, but C-DMRCJ can effectively control the interference loop difference, achieving more stable interference performance compared to G-DMRCJ.

[0080] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for designing and evaluating a distributed multi-source circular array reverse cross-eye interference configuration, characterized in that, The method includes: distributed cross-eye jammers outside the platform perform distributed positioning on a single-pulse radar, and construct a C-DMRCJ with the single-pulse radar as the center; an evaluation model of the interference performance of the distributed multi-source circular array reverse cross-eye jammer C-DMRCJ against the single-pulse radar is established under the scenarios of isolated platform reflected echo and considering platform echo, and the single-pulse ratio, total cross-eye gain and single-pulse indication angle of C-DMRCJ are obtained under the scenarios of isolated platform reflected echo and considering platform echo; a calculation model of the interference loop difference caused by the configuration of C-DMRCJ is constructed to obtain the interference loop difference caused by distributed positioning error; in, The monopulse radar is located at the origin, and its aperture spacing is... The distance from its center to the center of each interference loop is r The angle of its line of sight relative to the protected platform target is Its line of sight relative to the interference loop n The turning angle in the center direction is C-DMRCJ consists of 2 N Composed of several antenna array elements, totaling N One interference loop, antenna array element n and antenna array element 2 N - n +1 forms an interference loop n Its baseline length is The baseline length is consistent with the feeder length, and each interference loop is distributed around the protected platform target according to a given strategy; assuming interference loop 1 is the outermost interference loop of the jammer, the interference loop... n The angle of rotation relative to the radar center direction is Interference loop n The angle subtended by the center relative to the radar line of sight is Interference loop n The distance from the center to the radar line of sight is The half-angle of the jammer antenna direction relative to the center direction of jamming loop n Approximately expressed as ; The C-DMRCJ anti-monopulsive radar jamming performance evaluation model under isolated platform reflected echo includes: Radar line-of-sight to jammer antenna array element n With 2 N - n The included angles of +1 are respectively Then the single-pulse radar sum and difference channels are in The normalized gains in the directions are respectively (1) (2) Incorporating the reverse characteristics of the jammer antenna array and transforming it using basic trigonometric functions, the total echo of the sum and difference channels of a monopulse radar is expressed as follows: (3) (4) in, , , The phase constant in free space. , Wavelength; This indicates a poor interference loop. and Interference loops n The amplitude and phase; Indicates the system modulation parameters. and Interference loops n The system modulation amplitude ratio and phase difference; , For monopulse radar antenna beam, For the jammer antenna beam; at this time, the single-pulse ratio of C-DMRCJ is expressed as (5) When satisfied hour, As it approaches zero, then... Because the jammer is located in the far field of radiation of the monopulse radar antenna, there is ,So If the gain is very small, then the gain of the jammer antenna and radar antenna can be approximated, i.e. , , ;because Therefore, when the jammer is located in the far field of radiation of the monopulse radar, that is... At that time, there is And from Then there is as well as When considering the above approximation, equation (5) simplifies to (6) in, The cross-eye gain of C-DMRCJ, i.e. (7) The second term on the right side of equation (6) represents the angle measurement error introduced by the C-DMRCJ monopulse radar; when the isolation platform reflects the echo, the magnitude of the angle measurement error is mainly related to the cross-eye gain and Relevant; in theory when and When the denominator in equation (7) approaches 0, the cross-eye gain is at its maximum, which will cause the largest angle measurement error for the monopulse radar. The trigonometric relationship between the single pulse ratio and the single pulse indication angle is used to represent the single pulse indication angle. Represented as (8)； The C-DMRCJ jamming performance evaluation model for monopulse radar under platform reflected echoes includes: To uniformly represent the echoes of each distributed jammer platform and the echoes of the protected platform, let the angle between the line of sight of the monopulse radar and the point target of each distributed platform be... , ;when hour, ;when hour, At this time, the monopulse radar is in the direction The normalized sum and difference channel gains are respectively (9) (10) in, For single-pulse radar beams in direction The gain on the platform; the sum and difference channel echoes of the targets at each platform are respectively expressed as... (11) (12) Among them, when hour, That is , , These are the characterization parameters for the radar cross section (RCS) of each distributed jamming platform; when season ,but Indicates the RCS of the protected platform; Next, the single-pulse radar indication angle considering the platform reflected echo is modeled; when considering the platform reflected echo, the total single-pulse ratio is obtained by normalizing the total difference channel echo from the sum channel echo; let That is, the jammers rotate at equal angles, and The sum and difference channel echoes are represented as (13) (14) in, , , , and , These represent the amplitude and phase of the reflected echoes from the protected platform and each distributed jamming platform, respectively; the total single-pulse ratio considering the platform reflected echoes is... (15) Total cross-eye gain is expressed as (16) Therefore, the cross-eye gain in equation (8) is... Replace with total cross-eye gain This yields the expression for the single-pulse indicator angle considering the platform's reflected echo.

2. The method for designing and evaluating the distributed multi-source circular array reverse cross-eye interference configuration as described in claim 1, characterized in that, When considering the platform's reflected echo, the relationship between angle measurement error and scene geometry is as follows. , Jammer system parameters , and platform RCS , related.

3. The method for designing and evaluating the distributed multi-source circular array reverse cross-eye interference configuration as described in claim 1, characterized in that, The calculation model for the interference loop difference caused by the configuration of C-DMRCJ includes: For interference loop n The transmission distance of the interference signal emitted by the interference antenna in the middle. r For interference loop n The distance from the center to the monopulse radar, For interference loop n The length of the interference baseline, For interference loop n The angle of rotation relative to the radar center direction. For the interfering antenna relative to the interfering loop n The half-angle in the center direction; at this time, the interference loop... n The signal transmission path length is approximately expressed as: (17) In C-DMRCJ, because the baseline lengths of all loops are equal, the interference loops n Interference loop m The total interference loop difference between them is expressed as: (18) This interference loop difference causes a phase difference between the interference loops: (19)。 4. The method for designing and evaluating the distributed multi-source circular array reverse cross-eye interference configuration as described in claim 3, characterized in that, In C-DMRCJ, Therefore .

5. The method for designing and evaluating the distributed multi-source circular array reverse cross-eye interference configuration as described in claim 4, characterized in that, make This can completely eliminate the interference loop difference caused by the interference configuration, i.e. In other words, C-DMRCJ provides precise dynamic compensation to avoid large interference loop differences to a certain extent.

6. The method for designing and evaluating the distributed multi-source circular array reverse cross-eye interference configuration as described in claim 3, characterized in that, C-DMRCJ is a two-ring four-element C-DMRCJ.

7. The method for designing and evaluating the distributed multi-source circular array reverse cross-eye interference configuration as described in claim 6, characterized in that, Obtaining the interference loop difference caused by distributed positioning errors includes: and This represents the positioning error of a distributed cross-eye jammer against a monopulse radar in two orthogonal directions. and These represent the actual distances from the center of interference loop 1 and the center of interference loop 2 to the monopulse radar, respectively. and These are the actual rotation angles of the center of interference loop 1 and the center of interference loop 2 relative to the radar center direction, respectively, and let... , Therefore, the above parameters satisfy the following relationship: (20) (21) (22) (23) in, , , To actually interfere with the loop n The distance from the center to the monopulse radar, For interference loop n The length of the interference baseline, For interference loop n The actual angle of rotation relative to the radar center direction. n Choose 1 and 2; the total interference loop difference between interference loop 1 and interference loop 2 is: (24) As can be seen from equations (20)-(24), the interference loop error of C-DMRCJ depends on the positioning error of the distributed cross-eye jammer on the monopulse radar in the longitudinal direction. Size.

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