CN-115276605-B - Design method of transmitting sub-aperture frequency control array MIMO radar receiving and transmitting filter system

CN115276605BCN 115276605 BCN115276605 BCN 115276605BCN-115276605-B

Abstract

The invention discloses a design method of a transmitting sub-aperture frequency control array MIMO radar receiving and transmitting filter system, which is implemented according to the following steps of step 1, obtaining a receiving signal and SINR of the transmitting sub-aperture frequency control array MIMO radar in an interference environment, step 2, establishing a transmitting and receiving wave beam optimization problem, and step 3, solving the receiving and transmitting filter optimization design problem of the transmitting sub-aperture frequency control array MIMO radar. The invention solves the problem that the anti-interference effect is limited due to the fact that only the receiving filter is optimized in the prior art, and improves the output SINR level and the anti-interference effect.

Inventors

DING ZIHANG
XIE JUNWEI
HUANG JIEYU
QI CHENG
YANG XIAO
ZHANG GANGSHENG

Assignees

中国人民解放军空军工程大学

Dates

Publication Date: 20260512
Application Date: 20220729

Claims (5)

1. The design method of the transmitting sub-aperture frequency control array MIMO radar receiving and transmitting filter system is characterized by comprising the following steps of: step 1, acquiring a received signal and SINR of a transmitting sub-aperture frequency control array MIMO radar in an interference environment; step2, establishing a transmitting and receiving beam optimization problem; step 3, solving the problem of the optimal design of a receiving and transmitting filter of the transmitting sub-aperture frequency control array MIMO radar; The step 1 is specifically implemented according to the following steps: Step 1.1, obtaining a receiving target signal of a transmitting sub-aperture frequency control array MIMO radar; by means of a model of a narrow-band transmitting sub-aperture frequency-controlled array MIMO system, a transmitting array comprises M transmitting array elements, the transmitting array is divided into K subarrays, and each subarray comprises Each array element, the frequency deviation of the transmitting array element is The receiving array comprises N receiving array elements, and the expression that the signal transmitted by the kth subarray reaches the target position is: (1) Wherein, the Representing the transmit weight vector of the kth subarray, Indicating the operation of the transpose, Is the baseband signal transmitted by the kth subarray, Is the time delay of the radar to the target, The steering vectors are transmitted for the sub-arrays, An angle that is the target; after the received signal is processed by a matched filter in a receiving system, the signal vector form of the received target signal is expressed as follows: (2) (3) (4) (5) Wherein, the , Mean value 0 and covariance matrix 0 Is used for the complex gaussian white noise vector of (c), A reflectance of the target; In order to receive the steering vector, Is a transmit filter vector; When there is an object of interest and P interfering signals in the space domain, the received signal vector is expressed as: (6) Wherein, the , The complex reflection coefficient and the reflection coefficient of the p-th interference respectively representing the target, and the received signal is sent to the receiving filter Processing, wherein the filtered signals are as follows: (7); step 1.2, obtaining an SINR (signal to interference ratio) output by a receiving filter of a receiving end of the MIMO radar with the transmitting sub-aperture frequency control array; (8) (9) (10) Wherein, the Representing a conjugate transpose operation; step 2 introduces the maximum energy constraint of subarray array elements, and constructs the optimization problem of a receiving and transmitting filter with the maximum SINR as a criterion: (11) Wherein, the Representing an identity matrix of dimension K, Represents a matrix in which the elements except the ith diagonal element is 1, the other elements are all 0, Representing the power limit value of the ith transmit element of each subarray.
2. The method for designing a transmitting sub-aperture frequency control array MIMO radar transceiver filter system according to claim 1, wherein the specific steps of step 3 are as follows: Step 3.1, receiving filter design; step 3.2, designing a transmitting wave beam; and 3.3, circularly solving the optimization problem of the receiving filter and the transmitting filter.
3. The method for designing a transmitting sub-aperture frequency control array MIMO radar transceiver filter system according to claim 2, wherein the specific steps of step 3.1 are as follows: Fixed emission filter Equation (11) translates into a receive filter optimization problem: (12) The optimal solution of the receiving filter is: (13)。
4. the method for designing a transmitting sub-aperture frequency control array MIMO radar transceiver filter system according to claim 3, wherein the specific steps of step 3.2 are as follows: Fixed receiving filter Equation (11) translates into emission filter optimization problem: (14) (15) (16) For equation (14), introducing an auxiliary variable, and using a semi-positive relaxation algorithm, the optimization problem in equation (14) is equivalent to: (17) Wherein, the Representing the auxiliary variable; Let the parameter to the left of the first constraint in (17) , As a constant and related to the value of the objective function in step 3.1, equation (17) translates into: (18) Determining the value of t in the limiting condition as the SINR value obtained after optimizing the receiving filter in the iteration, substituting t into the formula (18), and solving the formula (18) by adopting a convex optimization tool box to obtain ; Obtaining L independent complex Gaussian random vectors distributed in the same way The sample was taken out of the sample, These vectors need to be processed to meet the power limit of the transmit filter: (19) Selection of , A vector for maximizing SINR , I.e. the designed transmit filter.
5. The method for designing a transmitting sub-aperture frequency-controlled array MIMO radar transceiver filter system according to claim 4, wherein in step 3.3, in each iteration process, the transmitting filter and the receiving filter are fixed in sequence, and are respectively optimally designed, and the optimized SINR and the optimized solution of the transmitting and receiving filters in the current iteration are recorded, and the SINR is used as an auxiliary variable in the next iteration And taking the solution of the transmitting and receiving filter as the initial solution of the next iteration until the absolute value difference of SINR obtained after two times of optimization before and after one iteration is smaller than the preset iteration stop condition, and outputting the solution of the current transmitting and receiving filter.

Description

Design method of transmitting sub-aperture frequency control array MIMO radar receiving and transmitting filter system Technical Field The invention belongs to the technical field of radars, and relates to a design method of a transmitting sub-aperture frequency control array MIMO radar receiving and transmitting filter system. Background The frequency control array MIMO radar transmits signals with micro frequency offset through different transmitting array elements, and combines the advantages of the frequency control array and the MIMO technology, so that the wave beam of the frequency control array MIMO radar is related to the angle and the distance in two dimensions. The transmitting sub-aperture refers to dividing a transmitting array of the frequency control array MIMO radar into a plurality of subarrays, and signals transmitted by each subarray are mutually orthogonal. The expansion of the degree of freedom and the introduction of the frequency offset enable the transmitting sub-aperture frequency control array MIMO radar to solve the problem that the conventional phased array radar is difficult to solve. The electromagnetic environment is more and more complex, the influence of interference signals on the radar system is larger, and a transceiving filter system needs to be reasonably designed to improve the anti-interference and detection capability of the radar system. The prior art generally has a wider research on the design problem of a receiving filter of a conventional frequency control array MIMO radar, but lacks a research on the joint design of transmitting sub-aperture MIMO radar receiving and transmitting filters. The prior art also has the problems of high calculation complexity of a design method, limited performance of obtaining Signal-to-interference-and-noise Ratio (SINR) and the like. Disclosure of Invention The invention aims to provide a design method of a transmitting sub-aperture frequency control array MIMO radar receiving and transmitting filter system, which solves the problem that the anti-interference effect is limited due to the fact that only a receiving filter is optimized in the prior art, and improves the output SINR level and the anti-interference effect. The technical scheme adopted by the invention is that the design method of the transmitting sub-aperture frequency control array MIMO radar receiving and transmitting filter system is implemented according to the following steps: step 1, acquiring a received signal and SINR of a transmitting sub-aperture frequency control array MIMO radar in an interference environment; step2, establishing a transmitting and receiving beam optimization problem; And step 3, solving the problem of the optimal design of the receiving and transmitting filter of the transmitting sub-aperture frequency control array MIMO radar. The invention is also characterized in that: the step 1 is specifically implemented according to the following steps: Step 1.1, obtaining a receiving target signal of a transmitting sub-aperture frequency control array MIMO radar; Through the model of the narrow-band transmitting sub-aperture frequency control array MIMO system, the transmitting array comprises M transmitting array elements, the transmitting array is divided into K subarrays, each subarray comprises M T = M-K+1 array elements, the frequency offset of the transmitting array elements is delta f, the receiving array comprises N receiving array elements, and the expression that the signal transmitted by the kth subarray reaches the target position is: Wherein, the Representing the transmit weight vector of the kth subarray, (-) T represents the transpose operation,Is the baseband signal transmitted by the kth subarray, τ r =r/c is the radar-to-target time delay,Transmitting a guide vector for the subarray, wherein theta is the angle of the target; after the received signal is processed by a matched filter in a receiving system, the signal vector form of the received target signal is expressed as follows: y=βΘ(θ,r)u+v (2) A(θ,r)=diag(as(r)⊙b(θ)) (4) as(r)＝[1,ej2πΔfr/c,…,ej2π(K-1)Δfr/c]T (5) Wherein b (θ) = [ b 1,b2,...,bK]T, v represents a mean value of 0, and the covariance matrix is Beta is the reflection coefficient of the target, a r(θ)＝[1,ej2πdsin(θ)/λ,…,ej2π(N-1)dsin(θ)/λ]T is the receiving guide vector,Is a transmit filter vector; When there is an object of interest and P interfering signals in the space domain, the received signal vector is expressed as: Wherein, beta 0,βp respectively represents the complex reflection coefficient of the target and the reflection coefficient of the p-th interference, and sends the received signal to the receiving filter Processing, wherein the filtered signals are as follows: x=wHy (7); step 1.2, obtaining an SINR (signal to interference ratio) output by a receiving filter of a receiving end of the MIMO radar with the transmitting sub-aperture frequency control array; Wherein (-) H represents a conjugate transp