Method for implementing frequency control array jamming signal against space-time adaptive processing of airborne MIMO radar

Abstract

The application discloses a frequency control array jamming signal implementation method for countering space-time adaptive processing of airborne MIMO radar, and belongs to the technical field of radar jammer design based on frequency control array. The application firstly obtains jamming signals by intercepting radar signals and storing and processing the jamming signals through digital radio frequency modulation based on the frequency control array jammer, and then loads a deceptive delay on the jamming signals; after different frequency offsets are added to different radiating antennas of the frequency control array jammer, the jamming signals are transmitted to the ground in the form of array antennas, and after being reflected by the ground, frequency control array scattering jamming signals are generated and received by the airborne radar; the airborne radar performs space-time adaptive processing on echo data to resist jamming signals. The frequency control array scattering jamming signals adopted by the application can change the rank of the clutter covariance matrix of the airborne radar by changing the frequency offset, thereby affecting the degree of freedom of the clutter; and the frequency offset can affect the notch of the STAP improvement factor of the airborne radar, thereby affecting the STAP anti-jamming performance of the radar.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of radar jammer design based on frequency diverse array (FDA), and particularly relates to a frequency diverse array jamming signal implementation method for countering space-time adaptive processing of airborne MIMO radar. BACKGROUND

[0002] The scatter bombing jamming signal is to radiate the received radar transmitting signal to the ground with high power, and the scatter bombing jamming signal and the ground clutter signal are received by the radar after being reflected by the ground. The scatter bombing jamming signal has been effectively used to counter the airborne synthetic aperture radar, and it aims to change the Doppler frequency of the scatter bombing jamming signal, thereby generating a Doppler-related jamming signal, so as to reduce the improvement factor (IF) of the radar receiver and deteriorate the radar anti-jamming performance.

[0003] The space-time adaptive processing (STAP) technology can effectively complete the jamming suppression in the moving target detection scene, and it uses the relationship between the array steering vector and the Doppler correlation vector to jointly complete the radar anti-jamming in two dimensions, especially for the Doppler-related jamming signal. The documents "STAP scatter bombing jamming method based on clutter extension" and "Analysis of the influence of scatter bombing jamming on space-time adaptive processing radar" propose a method for countering the space-time adaptive processing of airborne radar by using the scatter wave jamming, but due to the consistency of the phase frequency characteristics of the jamming signal and the radar transmitting signal, the scatter wave jamming can still be effectively suppressed under the condition of known prior information. Therefore, in order to improve the effectiveness of the scatter bombing jamming against the space-time adaptive processing technology of the radar and reduce the jamming suppression ability of the radar, a new jamming technology needs to be invented and designed. SUMMARY

[0004] The present application aims at: in order to reduce the STAP anti-jamming performance of the airborne radar and make up for the deficiency of the existing scatter bombing jamming technology, the present application proposes a scatter bombing jamming signal based on frequency diverse array for countering the STAP anti-jamming of the airborne radar, so as to reduce the jamming suppression performance of the radar.

[0005] In order to achieve the above-mentioned target, the design scheme adopted by the present application is as follows:

[0006] The frequency diverse array jamming signal implementation method for countering the space-time adaptive processing of the airborne MIMO radar comprises the following steps:

[0007] Step 1: transmitting the frequency diverse array jamming signal to the airborne MIMO radar based on the frequency diverse array jammer:

[0008] Step 101, the frequency control array jammer intercepts the radar signal of the airborne MIMO radar;

[0009] Step 102, the frequency control array jammer carries out digital radio frequency modulation storage processing on the intercepted radar signal to obtain the jamming signal, including sampling, storage, jamming modulation processing and replication, and then loads the deception delay on the obtained jamming signal;

[0010] Step 103, after different frequency offsets are added to different radiating antennas of the frequency control array jammer, the jamming signal (i.e. frequency control array jamming signal) is transmitted to the ground in the form of an array antenna, and after being reflected by the ground, the frequency control array scattering jamming signal is generated and received by the airborne MIMO radar;

[0011] Step 2, the airborne MIMO radar carries out space-time adaptive processing on the echo data (including target signal and frequency control array scattering jamming signal) to resist interference:

[0012] After each fast time sampling unit of the received echo data of the airborne MIMO radar is matched filtered and sampled, space-time data (i.e. matched filtering result) is obtained according to the fast time distance gate sampling, which contains target signal, scattering jamming signal, clutter signal and noise;

[0013] The airborne MIMO radar carries out space-time adaptive processing on the space-time data to complete interference suppression.

[0014] Further, in step 1, the kth pulse signal of the intercepted radar signal of the frequency control array jammer is represented as:

[0015]

[0016] Wherein, represents the transmission steering vector of the airborne MIMO radar, u(t-τ j represents the transmission baseband waveform vector of the airborne MIMO radar, ξ j is the scattering coefficient of the jammer, τ j =R j / c is the propagation time delay of the jamming signal, c represents the speed of light, f0 is the transmission signal carrier frequency, T represents the pulse signal period, and t represents the sampling time;

[0017] The kth pulse jamming signal transmitted by the pth radiating antenna of the frequency control array jammer is:

[0018]

[0019] Wherein, ρ p represents the pth radiating antenna coefficient of the frequency control array jammer, and Δf' represents the frequency offset added by the frequency control array jammer. d represents the delay of the signal propagating through the jammer's antenna array. j The spacing between the jammer's antenna arrays is represented by , and P represents the number of radiating antennas of the frequency-controlled array jammer.

[0020] Furthermore, the airborne MIMO radar is a MIMO transceiver co-located airborne radar composed of S transmitting antennas and N receiving antennas.

[0021] Furthermore, in step 2, the vector of the k-th pulse signal about the target received by the N receiving elements of the airborne MIMO radar is:

[0022]

[0023] in, Represents the MIMO radar receive steering vector, u(t-τ) t ) represents the MIMO radar receive baseband waveform vector, τ t =R t / c represents the propagation delay of the interference signal;

[0024] The N receiving elements of the airborne MIMO radar receive the k-th pulse signal of the pitch-scatter jamming emitted by the frequency-controlled array jammer, reflected from the i-th ground scattering point:

[0025]

[0026] Furthermore, in step 2, for the target signal, the space-time data obtained by the airborne MIMO radar is represented as follows:

[0027]

[0028] in, Represents the time-domain Doppler vector. Represents the Kronecker product;

[0029] For frequency-controlled array-based scattering jamming signals, the space-time data obtained by the airborne MIMO radar can be expressed as:

[0030]

[0031] Among them, Υ (FDA) This represents the spectral leakage matrix caused by the frequency offset of the jammer;

[0032] The number of ground scatterers for the echo signal is defined as N. r Then N r The composite echo signal vector of an equidistant loop composed of ground scatterers is represented as follows:

[0033] For the clutter signal, the clutter data reflected by the i-th ground scatter after matched filtering is represented as:

[0034]

[0035] Where, ξ i (R) represents the scattering coefficient of the i-th ground clutter scatterer; define N c represents the number of ground scatterers of the clutter signal, then the clutter signal vector of the equidistant ring composed of N c ground scatterers is represented as

[0036] The technical solutions provided by the present application at least bring the following beneficial effects:

[0037] The frequency control array scattering type jamming of the present application can change the rank of the airborne radar clutter covariance matrix by changing the frequency offset, thereby affecting the clutter degree of freedom; the frequency control array scattering type jamming can affect the notch of the airborne radar STAP improvement factor by changing the frequency offset, thereby affecting the radar STAP anti-jamming performance. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0039] Figure 1 The antenna structure diagram of the frequency control array jammer proposed by the present application.

[0040] Figure 2 The spatial coordinate scene diagram of the radar, the target to be detected, the frequency control array jammer and the ground scatter of the scattering type jamming signal involved in the present application.

[0041] Figure 3 The clutter characteristic spectrum of the airborne MIMO radar affected by the frequency control array scattering type jamming signal is shown.

[0042] Figure 4 The curve graph of the improvement factor changing with the normalized Doppler frequency under the influence of a smaller jamming frequency offset is shown.

[0043] Figure 5 The curve graph of the improvement factor changing with the normalized Doppler frequency under the influence of a larger jamming frequency offset is shown. DETAILED DESCRIPTION

[0044] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described in detail and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings can be arranged and designed using different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not only to limit the scope of the claimed present application, but only to represent selected embodiments of the present application.

[0045] The method for implementing the frequency control array jamming signal against space-time adaptive processing of the airborne MIMO radar provided by the embodiments of the present application is based on the frequency control array jammer, as shown in the figure, the composition structure of the frequency control array jammer includes: a plurality of radiating antennas, a jammer receiver and a digital radio frequency memory. Figure 1

[0046] The processing process of the radar signal based on the frequency control array jammer technology specifically includes:

[0047] Step J1, the frequency control array jammer intercepts the radar signal;

[0048] Step J2, the digital radio frequency memory technology (DRFM) performs high-speed sampling, storage, jamming modulation processing and copying on the received radar signal (i.e. based on the jammer receiver and the digital radio frequency memory), that is, based on the jammer receiver, the received radar signal is subjected to high-speed sampling, storage, jamming modulation processing, and then the jamming signal after modulation processing is stored in the digital radio frequency memory, and then the jamming signal obtained by jamming modulation processing is loaded with a deceptive delay;

[0049] Step J3, after different frequency offsets are added to different radiating antennas, the jamming signal is transmitted in the form of an array antenna, that is, the frequency control array jamming signal is transmitted.

[0050] Step J4, the frequency control array jamming signal is transmitted to the ground and is reflected by the ground to be received by the radar.

[0051] After the airborne radar receives the frequency control array jamming signal, the signal processing of STAP anti-jamming is performed, and the main process is as follows:

[0052] Step R1, the airborne radar receives the echo data of multiple array elements;

[0053] Step R2, after the airborne radar performs matched filtering sampling on each fast time sampling unit, space-time data is obtained according to the fast time range gate sampling, and the space-time data includes target signals, scatter jamming signals, clutter signals and noise.

[0054] ​Step R3, the airborne radar performs space-time adaptive processing on the matched filtering result to complete interference suppression.

[0055] Consider a frequency control array jammer composed of P radiating antennas and a MIMO transceiver co-located airborne radar composed of S transmitting antennas and N receiving antennas. Assume the number of coherent pulses is K, the height and flight speed of the airborne radar are H and v respectively a The spatial coordinate scene diagram of the airborne radar, the target to be detected, the jammer and the ground scattering points is shown in Figure 2 The azimuth angle of the target is The elevation angle is θ t The distance is R t = H / sinθ t , the speed is v t , and the scattering coefficient is ξ t . The azimuth angle of the jammer is The elevation angle is θ j The distance is R j = H / sinθ j . The azimuth angle and the elevation angle of the i-th ground scattering point on the equal-distance ring related to the clutter are θ i . The azimuth angle and the elevation angle of the i-th ground scattering point on the equal-distance ring related to the jamming signal are The spatial propagation distance from the jammer to the ground scattering point and then to the radar receiver is the target distance R t = H / sinθ t . As can be seen from Figure 2 , the ground scattering points causing the clutter signal form the clutter equal-distance trajectory Assume that the trajectory contains N c ground scattering points. The ground scattering points of the frequency control array projected scattering jamming signal form the jamming equal-distance trajectory Assume that the trajectory contains N r ground scattering points.

[0056] In step J1, the k-th pulse signal of the radar intercepted by the frequency control jammer can be expressed as

[0057]

[0058] wherein represents the MIMO radar transmitting steering vector, is the transpose of , u(t-τ j ) represents the MIMO radar transmitting baseband waveform vector, ξ j is the scattering coefficient of the jammer, and τ j= R j c is the propagation delay of the jamming signal, c represents the speed of light, f0 is the carrier frequency of the transmitted signal, T represents the period of the pulse signal, and t represents the sampling time.

[0059] The expressions of the radar transmitting steering vector and the radar transmitting baseband waveform vector are specifically as follows:

[0060]

[0061] u(t) = [A(t) A(t)e j2πΔft … A(t)e j2π(S-1)Δft ] T

[0062] wherein d is the spacing between MIMO radar transmitting elements, and are corresponding azimuth angle and elevation angle respectively, A(t) is a baseband envelope signal with unit energy and time length T p , and Δf ensures that the spectra of signals of different transmitting elements are not overlapped, and Δf >> 1 / T p .

[0063] In steps J2 and J3, the jamming signal of the kth pulse transmitted by the pth radiating antenna of the frequency control array jammer is:

[0064]

[0065] wherein represents the coefficient of the pth radiating antenna of the frequency control array jammer, Δf' represents an additional frequency offset of the frequency control array jammer, represents the delay of signal propagation in the jammer antenna array, and d j represents the spacing of the jammer antenna array.

[0066] In step R1, the kth pulse signal vector about the target received by the N receiving elements of the airborne MIMO radar is:

[0067]

[0068] wherein represents the MIMO radar receiving steering vector, u(t-τ t ) represents the MIMO radar receiving baseband waveform vector, τ t = R t c is the propagation delay of the jamming signal.

[0069]

[0070] The kth pulse signal received by the N receiving elements of the airborne MIMO radar about the diffuse scattering jamming transmitted by the i th ground scattering point of the frequency control array jammer is

[0071]

[0072] The space-time data of the MIMO radar matched filter output for the target signal can be expressed as

[0073]

[0074] where, represents the time-Doppler vector, represents the Kronecker product.

[0075]

[0076] The space-time data of the MIMO radar matched filter output for the frequency-controlled array scattering jamming signal can be expressed as

[0077]

[0078] where, (FDA) represents the spectrum leakage matrix caused by the jammer frequency offset, which can be expressed as

[0079]

[0080] The correlation vector g(R j ,Δf') can be expressed as

[0081] ρ=[ρ1 ρ2 … ρ P ]

[0082]

[0083]

[0084] z(t)=[1 e j2πΔf't … e j2π(P-1)Δf't ] T

[0085]

[0086] Thus, the synthetic echo signal vector of the equidistant ring composed of N r ground scatterers can be expressed as

[0087] For the clutter signal, the clutter data reflected by the i-th ground scatterer after the radar matched filtering can be expressed as

[0088]

[0089] where, denotes the scattering coefficient of the ith ground clutter scatterer. Thus, the clutter signal vector of an equi-spaced ring consisting of N c

[0090] In step R3, the space-time adaptive processing can be realized by using the minimum variance distortionless response (MVDR) beamformer for the airborne MIMO radar, and the optimal weight vector of the filter can be expressed as:

[0091]

[0092] where R u denotes the target-free covariance matrix, which consists of the jamming, clutter and noise:

[0093]

[0094] where n denotes the zero-mean Gaussian white noise sample sequence after the matched filtering of the MIMO radar, and the variance is E{} denotes the mathematical expectation.

[0095] The improvement factor of the space-time adaptive processing of the MIMO radar can be expressed as:

[0096]

[0097] The rank of the target-free covariance matrix and the notch problem of the IF of the embodiment of the present application are analyzed below to illustrate the effectiveness of the transmitting of the scatter-jamming by the frequency control array jammer against the MIMO-STAP radar.

[0098] (1) The rank of the clutter+jamming covariance matrix:

[0099] According to the foregoing, the clutter covariance matrix can be expressed as

[0100]

[0101] The scatter-jamming covariance matrix can be expressed as

[0102]

[0103] where

[0104]

[0105]

[0106] ​

[0107]

[0108] And Ξ (R) and (J) denote the diagonal matrix composed of the scattering matrix of the clutter scatterers and the jammer scatterers, respectively.

[0109]

[0110]

[0111] From the property of the matrix rank, we have:

[0112]

[0113] From the above derivation, we can change the element index of V c (R) and V c (R) according to

[0114]

[0115]

[0116] where, Let we can get:

[0117]

[0118] The above derivation shows that:

[0119]

[0120] That is, the scattering jamming signal of the frequency control array will increase the rank of the clutter covariance matrix of the airborne MIMO radar, and increase the clutter degree of freedom.

[0121] (2) The offset of the notch of the STAP improvement factor.

[0122] From the above derivation, the scattering jamming signal mainly affects the transmitting spatial frequency dimension, that is, The scattering jamming signal can make the notch of the improvement factor curve shift, and the shift amount is directly related to the frequency offset.

[0123]

[0124] where,

[0125] The influence of the frequency control array jammer on the airborne MIMO radar is simulated according to the parameters in Table 1, and the rank of the clutter covariance matrix and the notch of the STAP improvement factor curve are mainly analyzed to change with the frequency offset of the jammer, so as to show the technical advantages of the method of the embodiment of the application.

[0126] Table 1 Parameter setting

[0127]

[0128] Figure 3 The clutter characteristic spectrum of the airborne MIMO radar affected by the frequency control array scattering jamming signal is shown, and the rank of the clutter + jamming covariance matrix can be obviously seen to change with the jamming frequency offset Δf', wherein Δf' = 0 kHz represents a traditional jammer as a comparative experiment. It can be obviously seen that when Δf' ≠ 0 kHz, the clutter eigenvalue increases, which indicates that the frequency control array scattering jamming signal causes the clutter to expand, resulting in an increase in the clutter degree of freedom. Figure 3 The simulation results in Table 1, Figure 1, Figure 2, Figure 3, Figure 4, Figure 5, Figure 6, Figure 7, Figure 8, Figure 9 and Figure 10 conform to the conclusions of the theoretical analysis of the method of the embodiment of the application.

[0129] Figure 4 The improvement factor curves with the normalized Doppler frequency under the influence of different small jamming frequency offsets are shown, wherein Δf' = 0 kHz represents a traditional jammer as a comparative experiment. It can be seen from the figure that as Δf' increases, the notch of the improvement factor at the zero Doppler frequency expands, which indicates that the clutter suppression effect of the radar space-time adaptive processing becomes poor.

[0130] Figure 5 The improvement factor curves with the normalized Doppler frequency under the influence of different large jamming frequency offsets are shown, wherein Δf' = 0 kHz represents a traditional jammer as a comparative experiment. It can be seen from the figure that Δf' can adjust the position of the notch of the improvement factor curve, and the notches of different jamming frequency offsets will be at different Doppler frequencies, Figure 4 and Figure 5 The simulation results in Table 1, Figure 1, Figure 2, Figure 3, Figure 4, Figure 5, Figure 6, Figure 7, Figure 8, Figure 9 and Figure 10 conform to the conclusions of the theoretical analysis of the method of the embodiment of the application.

[0131] The above theoretical analysis and simulation experiments show the effectiveness of the frequency control array jammer scattering jamming against the space-time adaptive processing of the airborne MIMO radar.

[0132] Embodiment

[0133] Consider that an airborne MIMO radar will detect a ground moving target, and the airborne radar detection scene is as shown in Figure 10. Figure 2The airborne radar flies along the X axis at the height of 300 m with the speed of 150 m / s. There is a moving target in the ground area of interest, which is 6 km away from the airborne radar and located at the azimuth angle of 90°. The airborne MIMO radar has 8 transmitting antennas and 8 receiving antennas, and transmits rectangular pulse signals to probe the target at the pulse repetition frequency of 20 kHz. The number of pulses in a coherent processing interval (CPI) is 8, the carrier frequency is 10 GHz, and the distance between the transmitting and receiving elements is half a wavelength.

[0134] The frequency control array jammer transmits the jamming signals, which are reflected by the ground and received by the radar array antenna together with the ground clutter. The number of the jammer radiating antennas is 4, and the distance between the antennas is half a wavelength. The frequency offset of the jammer is set to be different from 0 to 20 kHz. The specific working process of the frequency control array jammer is as follows: when the radar transmits the pulse signals to probe the target, the jammer intercepts the radar signals, copies and modulates the radar signals through the digital radio frequency memory, and transmits high-power frequency control array jamming signals to the ground after adding the frequency offset to the radiating antennas. The jamming signals reflected by the ground are received by the radar together with the clutter signals. The transceiving device of the frequency control array jammer is shown in Figure 1 .

[0135] The airborne MIMO radar receives the reflection signals from the target and the signals from the frequency control array jammer, and obtains the data sequence after sampling through the matched filter. The MIMO radar can complete the adaptive beam forming by using the MVDR spatial filtering to suppress the interference energy in the direction of 15°. Figure 3 The clutter eigenvalue spectrum affected by the frequency control array scatter jamming signals received by the airborne MIMO radar is shown. It can be seen that, compared with the conventional jammer technology (Δf' = 0 kHz), the frequency control array scatter jamming signals can increase the number of the non-zero eigenvalues of the clutter covariance matrix, resulting in the increase of the clutter degrees of freedom. As can be seen from the figure, the number of the large clutter eigenvalues increases continuously with the increase of the frequency offset, and the total number of the eigenvalues does not exceed twice the original clutter rank. Figure 4 The simulation diagram of the improvement factor of the airborne MIMO radar space-time adaptive processing varying with the normalized Doppler frequency under the condition of small jamming frequency offset is shown. Compared with the conventional jammer technology (Δf' = 0 kHz), the frequency control array scatter jamming signals with the frequency offset of 1.9 kHz and 2.3 kHz can expand the improvement factor at the zero Doppler frequency, and when the frequency offset increases to more than 2.6 kHz, a second notch appears in the improvement factor curve, and the position of the notch is related to the frequency offset. Figure 5Further, the situation of the notch of the improvement factor changing with the frequency offset is shown. With the further increase of the interference frequency offset, the notch of the improvement factor is shifted and the depth of the notch is reduced, which shows that the frequency control array interference signal can protect the target signal near the notch Doppler frequency, thereby reducing the detection of the target after the radar clutter suppression.

[0136] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

[0137] The above only describes some embodiments of the present application. For those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application.

Claims

1. A method for implementing frequency control array jamming signals against space-time adaptive processing of airborne MIMO radars, characterized in that, The method comprises the following steps: Step 1, transmitting a radio frequency control array jamming signal to an airborne MIMO radar based on a frequency control array jammer: Step 101, the frequency control array jammer intercepts the radar signal of the airborne MIMO radar; Step 102, the frequency control array jammer carries out digital radio frequency modulation storage processing on the intercepted radar signal to obtain a jamming signal, and loads a deception delay on the jamming signal obtained through adjustment processing; Step 103, after different frequency offsets are added to different radiating antennas of the frequency control array jammer, the jamming signal is transmitted to the ground in the form of an array antenna, and after being reflected by the ground, a frequency control array scattering jamming signal is generated and received by the airborne MIMO radar; Step 2, the airborne MIMO radar carries out space-time adaptive processing on the echo data to resist jamming: After each fast-time sampling unit of the received echo data of the airborne MIMO radar is matched filtered and sampled, space-time data is obtained according to fast-time distance gate sampling, and the space-time data contains target signals, scattering jamming signals, clutter signals and noise; The airborne MIMO radar carries out space-time adaptive processing on the space-time data to complete interference suppression; In step 1, the kth pulse signal of the radar signal intercepted by the frequency control array jammer is represented as: wherein, denotes the airborne MIMO radar transmit steering vector, denotes the azimuth and elevation angles of the jammer, respectively, denotes the airborne MIMO radar transmit baseband waveform vector, denotes the scattering coefficient of the jammer, denotes the propagation time delay of the jamming signal, the distance , denotes the airborne MIMO radar altitude, denotes the speed of light, denotes the transmit signal carrier frequency, T denotes the pulse signal period, and t denotes the sampling time; The kth pulse jamming signal transmitted by the pth radiating antenna of the frequency control array jammer is: wherein represents the pth radiation antenna coefficient of the frequency-controlled array jammer, represents the additional frequency offset of the frequency-controlled array jammer, represents the delay of the signal propagating in the jammer antenna array, represents the spacing of the jammer antenna array, and P represents the number of radiation antennas of the frequency-controlled array jammer.

2. The method of claim 1, wherein, The airborne MIMO radar is a MIMO transceiving co-located airborne radar composed of S transmitting antennas and N receiving antennas.

3. The method of claim 2, wherein, In step 2, the kth pulse signal vector about the target received by the N receiving elements of the airborne MIMO radar is: wherein denotes a MIMO radar receive steering vector, , are the azimuth and elevation angles of the target, respectively, is the scattering coefficient of the target, denotes a MIMO radar receive baseband waveform vector, is the propagation time delay of the target signal, t denotes the sampling time, and the target distance ; The kth pulse signal about the frequency control array scattering jamming reflected by the ith ground scattering point received by the N receiving elements of the airborne MIMO radar is: 。 4. The method of claim 3, wherein, In step 2, the space-time data obtained by the airborne MIMO radar for the target signal is represented as: wherein denotes the time-domain Doppler vector, denotes the Kronecker product; For the frequency control array scattering jamming signal, the space-time data obtained by the airborne MIMO radar can be represented as: wherein represents the spectrum leakage matrix caused by the jammer frequency offset; The number of ground scatterers defining the echo signal is denoted by The composite echo signal vector of an equidistant ring consisting of ground scatterers is then given by ; For the clutter signal, the clutter data reflected by the ith ground scattering body after matched filtering is represented as: wherein, denotes the scattering coefficient of the ith ground clutter scatterer; defined as denotes the number of ground scatterers of the clutter signal, then the clutter signal vector of an equidistant ring consisting of ground scatterers is denoted by .

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