CN117741582B - Multi-dimensional domain coding-based main lobe interference resisting method and system for array radar - Google Patents

Abstract

The present invention discloses a method and system for array radar anti-mainlobe interference based on multi-dimensional domain coding, including obtaining a received signal, mixing the received signal to obtain a mixed signal; performing slow-time phase compensation, discrete Fourier transform, signal separation and pulse compression processing on the mixed signal in sequence to obtain a pulse compressed signal; obtaining a total received signal according to the pulse compressed signal, interference signal and noise; and obtaining an interference suppression result according to the total received signal. The present invention adopts a new radar system of multi-dimensional domain coding. Compared with the EPC-MIMO radar system, Doppler modulation is used to achieve radar transmission waveform separation, which overcomes the disadvantage that the orthogonality of the EPC-MIMO radar cannot meet the requirements when the interference power is very high, and improves the anti-interference ability of the MIMO radar.

Description

A method and system for array radar to resist main lobe interference based on multi-dimensional domain coding

Technical Field

The present invention belongs to the field of radar technology, and in particular relates to a method and system for array radar main lobe interference resistance based on multi-dimensional domain coding.

Background technique

Lan Lan et al. studied the mainlobe interference suppression method based on EPC-MIMO (Element Pulse Coding-Multiple Input Multiple Output) radar in their paper "Mainlobe interference suppression with element-pulse conding MIMO radar". The waveform separation was achieved by transmitting orthogonal coded waveforms, and the mainlobe interference suppression was achieved by coding around the element-pulse.

The existing EPC-MIMO radar based on element-pulse coding transmits orthogonal coded waveforms and realizes waveform separation by matching filtering at the receiving end. However, when the power of the forwarded interference is large enough, the orthogonality of the orthogonal coded waveform cannot be used to separate the interference signal, which will cause the EPC-MIMO radar's anti-interference capability to fail. In addition, the EPC-MIMO radar can only suppress interference signals from different range ambiguity intervals, and has insufficient ability to suppress interference with the same range ambiguity interval as the target echo.

Summary of the invention

In order to solve the above problems existing in the prior art, the present invention provides a method and system for array radar anti-main lobe interference based on multi-dimensional domain coding.

The technical problem to be solved by the present invention is achieved through the following technical solutions:

The present invention provides an array radar anti-main lobe interference method based on multi-dimensional domain coding, and the array radar anti-main lobe interference method comprises:

Acquire a received signal, and mix the received signal to obtain a mixed signal, wherein the mixed signal includes sub-pulses after mixing, N is the total number of receiving array elements, K is the total number of pulses, and L is the total number of sub-pulses in a pulse;

sequentially performing slow-time phase compensation, discrete Fourier transform, signal separation and pulse compression processing on the mixed signal to obtain a pulse compressed signal;

The total received signal is obtained according to the pulse compressed signal, the interference signal and the noise;

An interference suppression result is obtained according to the received total signal.

Optionally, the mixed sub-pulse is expressed as:

;

in, For the mixed / > The receiving element receives the first /> The first pulse of sub-pulses,/> is the complex amplitude of the point target, /> is the carrier frequency, /> ,/> is the distance between the point target and the radar, /> is the speed of light, is the total number of transmitting array elements, /> For the first/> The waveform transmitted by the transmitting array element, /> For quick time, /> is the coding coefficient, /> ,/> is the pulse delay number, /> is the array element spacing, /> is the angle between the point target and the radar, /> is the wavelength, /> is the target Doppler frequency, /> ,/> is the target speed, /> is the pulse repetition period, /> ,/> , ,/> .

Optionally, the mixed signal is subjected to slow-time phase compensation, discrete Fourier transform, signal separation and pulse compression processing in sequence to obtain a pulse compressed signal, including:

Performing slow time phase compensation on the mixed signal to obtain a compensated signal;

Performing discrete Fourier transform on the compensated signal in slow time to obtain a transformed signal;

Use the passband The transformed signal is filtered by a low-pass filter to obtain a filtered signal, wherein: is the pulse repetition frequency, /> is the total number of transmitting array elements;

Performing an inverse discrete Fourier transform on the filtered signal to obtain an inverse transformed signal;

Obtaining a separated signal according to the inverse transformed signal;

Stack all separated signals into one dimensional vector to obtain the stacked signal;

Performing fast time phase compensation on the stacked signal to obtain a fast time phase compensated signal;

Pulse compression is performed on the signal after the fast time phase compensation to obtain a pulse compressed signal.

Optionally, the compensated signal is expressed as:

;

in, For the first/> The first/> after the compensation of the transmitting array element The kth pulse received by the receiving array element is sub-pulses,/> is the complex amplitude of the point target, /> is the carrier frequency, /> ,/> is the distance between the point target and the radar, /> is the speed of light, /> is the angle between the point target and the radar, /> is the array element spacing, /> is the target Doppler frequency, ,/> is the target speed, /> is the wavelength, /> is the pulse repetition period, /> For the first/> The waveform transmitted by the transmitting array element, /> For quick time, /> is the pulse delay number, /> is the coding coefficient, /> ,/> ,/> , ,/> ,/> .

Optionally, the filtered signal is expressed as:

;

in, is the first one obtained after frequency filtering/> The mth transmitting element transmitted by the mth transmitting element is received by the mth receiving element/> sub-pulses,/> is the Doppler channel number, /> , ,/> is transposed,/> For the low-pass filter elements;

The separated signal is expressed as:

;

in, After separation, The kth pulse transmitted by the mth transmitting element is received by the receiving element. sub-pulses.

Optionally, the signal after the fast time phase compensation is expressed as:

;

in, The first / > received by N receiving array elements The first pulse of The signal after fast time phase compensation of sub-pulses,/> The first / > received by N receiving array elements The first pulse of The stacked signal of sub-pulses, To convert a vector into a diagonal matrix, /> is the fast time phase compensation vector,/> , For/> dimension column vector, /> ,/> ,/> , ,/> is the dot product, /> ,/> is the Kronecker product.

Optionally, the pulse compressed signal is expressed as:

;

in, For/> The pulse is compressed after the first pulse/> sub-pulses,/> , .

Optionally, the received total signal is expressed as:

;

in, To receive the total signal, /> is the interference signal,/> ,/> is the interference signal amplitude, /> ,/> , ,/> ,/> is the Doppler vector of the interference signal, /> , ,/> is the modulation speed of the interference signal, /> For noise.

Optionally, the interference suppression result is expressed as:

;

in, is the interference suppression result,/> ,/> is the conjugate transpose operation, is the sampling covariance matrix,/> .

The present invention also provides an array radar anti-main lobe interference system based on multi-dimensional domain coding, and the array radar anti-main lobe interference system comprises:

A mixing module is used to obtain a received signal and mix the received signal to obtain a mixed signal, wherein the mixed signal includes sub-pulses after mixing, N is the total number of receiving array elements, K is the total number of pulses, and L is the total number of sub-pulses in a pulse;

A processing module, used for sequentially performing slow-time phase compensation, discrete Fourier transform, signal separation and pulse compression processing on the mixed signal to obtain a pulse compressed signal;

A total signal generating module, used for obtaining a received total signal according to the pulse compressed signal, the interference signal and the noise;

The interference suppression module is used to obtain an interference suppression result according to the received total signal.

Compared with the prior art, the present invention has the following beneficial effects:

The present invention first mixes the received signal to obtain a mixed signal, then performs slow-time phase compensation, discrete Fourier transform, signal separation and pulse compression processing on the mixed signal in sequence to obtain a pulse compressed signal, and then obtains a total received signal based on the pulse compressed signal, the interference signal and the noise, and finally obtains an interference suppression result based on the total received signal. The present invention adopts a new radar system of multi-dimensional domain coding. Compared with the EPC-MIMO radar system, the present invention uses Doppler modulation to achieve the separation of radar transmission waveforms, overcomes the shortcoming that the orthogonality of the EPC-MIMO radar cannot meet the requirements when the interference power is very high, and improves the anti-interference ability of the MIMO radar. The present invention can not only suppress false targets in different distance ambiguity intervals, but also has a suppressive effect on false targets in the same distance ambiguity interval.

The present invention will be further described in detail below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic flow chart of a method for array radar main lobe interference prevention based on multi-dimensional domain coding provided by an embodiment of the present invention;

FIG2 is a distance-Doppler diagram of signal separation provided by an embodiment of the present invention;

FIG3 is a non-adaptive beamforming pattern in the transmit-receive spatial frequency domain provided by an embodiment of the present invention;

4 is a Capon power spectrum diagram of the transmit-receive spatial frequency domain provided by an embodiment of the present invention;

5 is a schematic diagram of a signal coherent accumulation result provided by an embodiment of the present invention when the method proposed by the present invention is not used;

FIG6 is a schematic diagram of a signal coherent accumulation result when using the method proposed by the present invention according to an embodiment of the present invention;

FIG7 is a schematic diagram of an array radar anti-main lobe interference system based on multi-dimensional domain coding provided by an embodiment of the present invention.

Detailed ways

The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

Embodiment 1

In the EPC-MIMO radar, there is a phase difference between different pulses related to the number of pulses and the number of array elements. The phase difference causes different steering vectors corresponding to different pulses. Therefore, the EPC-MIMO radar can achieve the purpose of interference suppression for signals in different distance ambiguity intervals. However, the necessary prerequisite for the EPC-MIMO radar to achieve the above functions is that the transmission signals of each transmitting array element must have a high orthogonality so that the subsequent radar can separate the signals transmitted by different channels. When there is deception interference in the environment, the common phase-coded orthogonal signal has low orthogonality. When the interference power is large, the cross-correlation peaks of each transmission signal forwarded by the jammer will drown the real target, which will have a great impact on the radar's target search, tracking and other functions. The present invention proposes a multi-dimensional domain coding system radar around space, slow time and fast time joint coding, which realizes the orthogonal transmission of the MIMO radar based on Doppler modulation, and suppresses the main lobe deception interference while achieving a good orthogonal waveform.

Please refer to FIG. 1, which is a flow chart of a method for array radar anti-main lobe interference based on multi-dimensional domain coding provided by an embodiment of the present invention. An embodiment of the present invention provides an array radar anti-main lobe interference method based on multi-dimensional domain coding, and the array radar anti-main lobe interference method includes:

Step 1: Obtain a received signal and mix the received signal to obtain a mixed signal, wherein the mixed signal includes The mixed sub-pulses are as follows: N is the total number of receiving array elements, K is the total number of pulses, and L is the total number of sub-pulses in one pulse.

Specifically, this embodiment sets up a co-located MIMO radar system with M transmitting array elements and N receiving array elements, and the echo of the reflected transmitting signal is received by the receiving array element, which is implemented as follows:

Assuming that the radar transmits K pulses within a CPI (Coherent Processing Interval), the The first/> The first pulse of The encoding of the sub-pulses can be designed as:

;

in, is the coding coefficient, /> ,/> is the total number of transmitting array elements.

Assume that there is a point target in the far field, and the angle and distance between the point target and the radar are and/> , and the pulse delay number is/> , under narrowband conditions, by the / > The receiving element receives the first /> The first pulse of sub-pulses/> for:

;

in, is the complex amplitude of the point target, /> For the first/> The waveform transmitted by the transmitting array element, /> For quick time, /> ,/> is the distance between the point target and the radar, /> is the speed of light, /> is the carrier frequency, /> is the target Doppler frequency, ,/> is the target speed, /> is the wavelength, /> is the pulse repetition period, /> is the signal round-trip propagation delay, ,/> is the angle between the point target and the radar, /> is the array element spacing, /> .

After that, the received signal is mixed to obtain a mixed signal, which includes The mixed sub-pulse is expressed as:

;

in, For the mixed / > The receiving element receives the first /> The first pulse of sub-pulses.

Step 2: sequentially perform slow-time phase compensation, discrete Fourier transform, signal separation and pulse compression processing on the mixed signal to obtain a pulse compressed signal.

Step 2.1, performing slow time phase compensation on the mixed signal to obtain a compensated signal.

Specifically, in order to separate The receiving array element receives the first /> The pulse signal sent by the transmitting array element needs to be sent to the first/> according to the specific number of pulses. The received signal of each receiving array element is subjected to slow time phase compensation, and the compensated signal can be expressed as:

;

in, For the first/> The first/> after the compensation of the transmitting array element The kth pulse received by the receiving array element is sub-pulses.

Step 2.2: Perform discrete Fourier transform on the compensated signal in slow time to obtain a transformed signal.

Specifically, compensation After the phase, when/> When, the The signal of each transmitting array element is moved to the Doppler zero frequency, and the compensated signal is discrete Fourier transformed to obtain the transformed signal.

Step 2.3, use the passband The transformed signal is filtered by a low-pass filter to obtain a filtered signal, wherein, /> is the pulse repetition frequency, /> .

Specifically, a passband of Low pass filter/> To filter out the signals in other frequency bands, the filtered signal is expressed as:

;

in, is the first one obtained after frequency filtering/> The mth transmitting element transmitted by the mth transmitting element is received by the mth receiving element/> sub-pulses,/> is the Doppler channel number, /> , ,/> is transposed,/> For the low-pass filter elements.

Step 2.4: Perform inverse discrete Fourier transform on the filtered signal to obtain an inverse transformed signal.

Specifically, the inverse transformed signal is expressed as:

;

in, For/> The inverse discrete Fourier transform result of .

Step 2.5: Obtain the separated signal based on the inverse transformed signal.

Specifically, take out Each element of can get the first/> The receiving array element receives the first /> The first/> The first pulse of sub-pulse signal, expressed as:

;

in, After separation, The kth pulse transmitted by the mth transmitting element is received by the receiving element. sub-pulses.

Step 2.6: Stack all separated signals into one dimensional vector, and the stacked signal is obtained, which is expressed as:

;

in, The first / > received by N receiving array elements The first pulse of The stacked signal of sub-pulses.

Step 2.7, perform fast time phase compensation on the stacked signal to obtain a fast time phase compensated signal.

Specifically, the phase difference between adjacent channels is eliminated by fast time phase compensation ,get:

;

in, The first / > received by N receiving array elements The first pulse of The signal after fast time phase compensation of sub-pulses,/> To convert a vector into a diagonal matrix, /> is the fast-time phase compensation vector, ,/> For/> dimension column vector, /> ,/> , ,/> , ,/> is the dot product, /> is the Kronecker product.

Step 2.8, performing pulse compression on the signal after fast time phase compensation to obtain a pulse compressed signal.

Here, the signal after pulse compression is expressed as:

;

in, For/> The pulse is compressed after the first pulse/> sub-pulses,/> , .

Step 3: Obtain the total received signal based on the pulse compressed signal, the interference signal and the noise.

According to the above signal processing flow, consider that the jammer intercepts and forwards the radar signal. Assume that the own radar is affected by the self-defense fast forwarding interference, and the distance ambiguity interval, angle and speed of the interference signal are the same as the target. In general, when the distance ambiguity interval of the forwarding interference signal is the same as the distance ambiguity interval of the target echo, the interference signal will inevitably lag behind the target echo in time. Considering that the jammer forwarding delay is greater than the pulse width, the interference signal and the target echo have no overlap in the time domain. Therefore, the first peak after the pulse compression must correspond to the real target. This feature can be used to determine the pulse leading edge of the target echo, and then fast-time phase compensation can be performed in the target echo area. The fast-time encoding phase of the interference signal, that is, , cannot be compensated normally, so the signal model of forwarding interference can be expressed as:

;

in, is the interference signal,/> is the interference signal amplitude, /> , ,/> ,/> ,/> is the Doppler vector of the interference signal, /> ,/> , The modulation speed of the interference signal is compensated for by fast time coding.

Therefore, different transmission spatial frequencies can be used to distinguish true and false targets. Subsequently, an adaptive beamformer can be constructed to suppress interference signals and accumulate target signals. The weight vector is expressed as:

;

in, To send and receive joint steering vectors, /> is the conjugate transpose operation, /> is the sampling covariance matrix. The final received signal of the radar contains the target, interference and noise, which can be expressed as:

;

in, To receive the total signal, /> For noise.

Step 4: Obtain interference suppression results based on the received total signal.

Here, the interference suppression result is expressed as:

;

in, is the interference suppression result.

The present invention first encodes the multi-dimensional domains of space, slow time and fast time around the transmitted signals of each array element. When the receiving end processes, the received signal is firstly compensated for the slow time phase, and then a discrete Fourier transform is performed to move the spectrum of the desired signal to zero frequency. Then, a low-pass filter is used to separate the signal to obtain the desired signal. After that, it is necessary to compensate for the fast time coding phase, and perform beamforming to complete target accumulation and interference suppression. The present invention adopts a new radar system of multi-dimensional domain coding. Compared with the EPC-MIMO radar system, Doppler modulation is used to realize the separation of radar transmission waveforms, which overcomes the disadvantage that the orthogonality of the EPC-MIMO radar cannot meet the requirements when the interference power is very high, and improves the anti-interference ability of the MIMO radar.

The present invention introduces phase coding in fast time, so compared with the EPC-MIMO radar, the present invention can not only suppress false targets in different distance ambiguity intervals, but also has a suppressive effect on false targets in the same distance ambiguity interval.

When the radar waveform emitted by the present invention is generated, it is only necessary to multiply a common emission waveform by different initial coding phases to obtain emission waveforms of different array elements and pulses. Therefore, the present invention is easy to implement and the required hardware structure is simple.

The present invention is further described below in conjunction with simulation experiments.

1. Simulation parameter settings:

Table 1 gives the radar system simulation parameters, and Table 2 gives the target parameters. It is assumed that the self-defense jammer generates two false targets in total, of which false target 1 is cross-pulse forwarding jammer and false target 2 is fast forwarding jammer.

Table 1 Simulation parameters of multi-dimensional domain coding radar system

Table 2 Target parameters

2. Simulation content and result analysis:

Simulation 1, under the simulation parameters of Tables 1 and 2 above, using the technology of the present invention, when the MIMO radar adopts a multi-dimensional domain coding method, the range-Doppler diagram during signal separation is shown in Figure 2. It can be seen that the transmitted signals of each array element are evenly arranged in the Doppler dimension under the effect of coding, so the transmitted signals can be separated by a low-pass filter.

The adaptive beamforming pattern in the transmit-receive spatial frequency domain is shown in Figure 3. The power spectrum of the received signal in the transmit-receive spatial frequency domain is shown in Figure 4. It can be seen that under the effect of coding, the power peak points of each sub-pulse of the interference signal and the power peak point of the target are located on different transmit spatial frequencies, so the radar can distinguish between the target and the interference signal.

Simulation 2, under the simulation parameters of Tables 1 and 2 above, the technology of the present invention is used to simulate the interference suppression of false targets. Figure 5 shows the signal coherent accumulation result when the present invention is not used. It can be seen that 2 power false targets appear in the accumulation result at this time. Figure 6 shows the signal coherent accumulation result after the MIMO radar uses multi-dimensional domain coding. It can be seen that the interference signals at the 4km and 2km positions have been suppressed at this time, which illustrates the effectiveness of the present invention.

The above simulation analysis and tests prove the correctness and effectiveness of the method proposed in the present invention.

Embodiment 2

Please refer to FIG. 7 , which is a main lobe interference prevention system for an array radar based on multi-dimensional domain coding provided by an embodiment of the present invention. The main lobe interference prevention system for an array radar provided by an embodiment of the present invention includes:

The mixing module is used to obtain the received signal and mix the received signal to obtain the mixed signal, wherein the mixed signal includes sub-pulses after mixing, N is the total number of receiving array elements, K is the total number of pulses, and L is the total number of sub-pulses in a pulse;

A processing module, used to sequentially perform slow-time phase compensation, discrete Fourier transform, signal separation and pulse compression processing on the mixed signal to obtain a pulse compressed signal;

A total signal generating module, used for obtaining a received total signal according to the pulse compressed signal, the interference signal and the noise;

The interference suppression module is used to obtain an interference suppression result according to the received total signal.

It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example.

Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art may understand and implement other variations of the disclosed embodiments by viewing the drawings and the disclosure. In the specification, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. Certain measures are recorded in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims (9)

1. A method for array radar anti-main lobe interference based on multi-dimensional domain coding, characterized in that the array radar anti-main lobe interference method comprises: A received signal is acquired, and the received signal is mixed to obtain a mixed signal, wherein the mixed signal includes N*K*L mixed sub-pulses, N is the total number of receiving array elements, K is the total number of pulses, L is the total number of sub-pulses in a pulse, and the coding of the l-th sub-pulse of the k-th pulse transmitted by the m-th transmitting array element is expressed as Φ _m,k,l =j2πγ(m-1)(k+l), γ is a coding coefficient, m＝1,2,…,M, M is the total number of transmitting array elements, k＝1,2,…,K, l＝1,2,…,L; sequentially performing slow-time phase compensation, discrete Fourier transform, signal separation and pulse compression processing on the mixed signal to obtain a pulse compressed signal; The total received signal is obtained according to the pulse compressed signal, the interference signal and the noise; The interference suppression result is obtained according to the received total signal, and the interference suppression result is expressed as: Among them, Y _l ′ is the interference suppression result, Y _l is the total received signal, H is the conjugate transpose operation,/> is the sampling covariance matrix,/> θ ₀ is the angle between the point target and the radar, /> is the Kronecker product, _λ0 is the wavelength, and d is the array element spacing. 2. The method for array radar anti-main lobe interference based on multi-dimensional domain coding according to claim 1, characterized in that the mixed sub-pulse is expressed as: Where _xn,l,k (t) is the lth sub-pulse of the kth pulse received by the nth receiving element after mixing, As _is the complex amplitude of the point target, _f0 is the carrier frequency, R ₀ is the distance between the point target and the radar, c is the speed of light, M is the total number of transmitting array elements, φ _m (t-τ ₀ ) is the waveform emitted by the mth transmitting array element, t is the fast time, γ is the coding coefficient, /> _ps is the pulse delay number, _θ0 is the angle between the point target and the radar, _fd0 is the target Doppler frequency, /> _v0 is the target speed, _Tr is the pulse repetition period, m＝1,2,…,M, n＝1,2,…,N, k＝1,2,…,K, l＝1,2,…,L. 3. The method for array radar anti-main lobe interference based on multi-dimensional domain coding according to claim 1 is characterized in that the mixed signal is subjected to slow time phase compensation, discrete Fourier transform, signal separation and pulse compression processing in sequence to obtain a pulse compressed signal, including: Performing slow time phase compensation on the mixed signal to obtain a compensated signal; Performing discrete Fourier transform on the compensated signal in slow time to obtain a transformed signal; Use the passband A low-pass filter is used to filter the transformed signal to obtain a filtered signal, wherein f _r is a pulse repetition frequency, and M is the total number of transmitting array elements; Performing an inverse discrete Fourier transform on the filtered signal to obtain an inverse transformed signal; Obtaining a separated signal according to the inverse transformed signal; All separated signals are stacked into a MN×1-dimensional vector to obtain a stacked signal; Performing fast time phase compensation on the stacked signal to obtain a fast time phase compensated signal; Pulse compression is performed on the signal after the fast time phase compensation to obtain a pulse compressed signal. 4. The array radar anti-main lobe interference method based on multi-dimensional domain coding according to claim 3 is characterized in that the compensated signal is expressed as: in, is the lth sub-pulse of the kth pulse received by the nth receiving element after compensating the ith transmitting element, As _is the complex amplitude of the point target, _f0 is the carrier frequency,/> _R0 is the distance between the point target and the radar, c is the speed of light, _θ0 is the angle between the point target and the radar, d is the array element spacing, _fd0 is the target Doppler frequency, /> v ₀ is the target speed, λ ₀ is the wavelength, _Tr is the pulse repetition period, φ _m (t-τ ₀ ) is the waveform emitted by the mth transmitting element, t is the fast time, p _s is the pulse delay number, γ is the coding coefficient,/> m＝1,2,…,M，i＝1,2,…,M，n＝1,2,…,N，k＝1,2,…,K，l＝1,2,…,L。 5. The method for array radar anti-main lobe interference based on multi-dimensional domain coding according to claim 4, characterized in that the filtered signal is expressed as: Wherein, _Xn,m,l,t (k′) is the lth sub-pulse transmitted by the mth transmitting element and received by the nth receiving element after frequency filtering, k′ is the Doppler channel number, k′＝0,1,…,K-1, [·] ^T is the transpose, H _LP (k′) is the k′th element of the low-pass filter; The separated signal is expressed as: in, It is the lth sub-pulse of the kth pulse transmitted by the mth transmitting array element and received by the nth receiving array element after separation. 6. The array radar anti-main lobe interference method based on multi-dimensional domain coding according to claim 5 is characterized in that the signal after the fast time phase compensation is expressed as: Where x′ _l,k (t) is the signal after fast time phase compensation of the lth sub-pulse of the kth pulse received by N receiving array elements, is the stacked signal of the lth sub-pulse of the kth pulse received by N receiving array elements, diag{·} is the vector converted into a diagonal matrix, g is the fast time phase compensation vector, /> 1 _N is an N×1 dimensional column vector, /> ⊙ is the dot product, is the Kronecker product. 7. The array radar anti-main lobe interference method based on multi-dimensional domain coding according to claim 6, characterized in that the pulse compressed signal is expressed as: Where, Ys _,l is the lth sub-pulse after pulse compression of K pulses, 8. The array radar anti-main lobe interference method based on multi-dimensional domain coding according to claim 7, characterized in that the received total signal is expressed as: Y _l =Y _s,l +Y _f,l +Y _n ; Among them, Y _l is the total received signal, Y _f,l is the interference signal, β _j is the interference signal amplitude,/> c(f _df ) is the Doppler vector of the interference signal, _vf is the modulation speed of the interference signal, and _Yn is the noise. 9. An array radar anti-main lobe interference system based on multi-dimensional domain coding, characterized in that the array radar anti-main lobe interference system comprises: A mixing module is used to obtain a received signal and mix the received signal to obtain a mixed signal, wherein the mixed signal includes N*K*L mixed sub-pulses, N is the total number of receiving array elements, K is the total number of pulses, L is the total number of sub-pulses in a pulse, and the coding of the lth sub-pulse of the kth pulse transmitted by the mth transmitting array element is expressed as Φ _m,k,l =j2πγ(m-1)(k+l), γ is a coding coefficient, m＝1,2,…,M, M is the total number of transmitting array elements, k＝1,2,…,K, l＝1,2,…,L; A processing module, used for sequentially performing slow-time phase compensation, discrete Fourier transform, signal separation and pulse compression processing on the mixed signal to obtain a pulse compressed signal; A total signal generating module, used for obtaining a received total signal according to the pulse compressed signal, the interference signal and the noise; An interference suppression module is used to obtain an interference suppression result according to the received total signal, wherein the interference suppression result is expressed as: Among them, Y _l ′ is the interference suppression result, Y _l is the total received signal, H is the conjugate transpose operation,/> is the sampling covariance matrix,/> θ ₀ is the angle between the point target and the radar, /> is the Kronecker product, _λ0 is the wavelength, and d is the array element spacing.