CN-121984477-A - Local mismatch filter design based on radar communication integrated waveform

CN121984477ACN 121984477 ACN121984477 ACN 121984477ACN-121984477-A

Abstract

The invention relates to a local mismatch filter design based on radar communication integrated waveforms, which comprises the steps of obtaining M discrete emission waveform vectors scheduled to be emitted in a coherent processing interval, constructing an optimization problem model based on the M emission waveform vectors, carrying out iterative solution on the optimization problem model by adopting an alternate direction multiplication method, and outputting M local mismatch filter coefficient vectors, wherein the M local mismatch filter coefficient vectors are respectively matched with the M discrete emission waveforms and are used for carrying out filtering processing on received echo signals at a receiving end of a radar communication integrated system so as to inhibit range side lobe modulation and improve the detection performance of a moving target. The method can be applied to receiving end processing, and can fundamentally inhibit RSM effect, so that clutter responses of different pulses can be effectively aligned and canceled in cancellation processing, and the detection capability of a moving target of a system under a strong clutter background is remarkably improved.

Inventors

LIU YONGJUN
DU YUYANG
TANG HAO
LIAO GUISHENG
DUAN YUHANG
TAO HAIHONG
ZENG CAO

Assignees

西安电子科技大学

Dates

Publication Date: 20260505
Application Date: 20260116

Claims (6)

1. A local mismatch filter design based on radar communication integrated waveforms, comprising: M discrete emission waveform vectors which are planned to be emitted by the radar communication integrated system in a coherent processing interval are obtained; Based on the M emission waveform vectors, constructing a weighted summation optimization problem model by taking a side lobe level of a minimized local mismatch filter output, similarity of filter outputs among different waveforms and signal-to-noise ratio loss as a joint optimization target; Carrying out iterative solution on the optimization problem model by adopting an alternate direction multiplier method, and outputting M partial mismatch filter coefficient vectors; The M local mismatch filter coefficient vectors are respectively matched with the M discrete emission waveforms and are used for carrying out filtering processing on the received echo signals at the receiving end of the radar communication integrated system so as to inhibit range side lobe modulation and improve the detection performance of the moving target.
2. The radar communication integration waveform-based local mismatch filter design of claim 1, wherein the optimization problem model has a computational expression of: ; ; ; ; Wherein, the 、 And Is an adjustable non-negative weight factor, ; Characterizing the maximum difference between the actual output and the corresponding desired low sidelobe filter output response vector among all filters corresponding to the M discrete transmit waveform vectors, Characterizing the average difference between the filter outputs between the different waveforms, The SNR loss within the coherent processing interval is characterized, 、 And Respectively is 、 And The normalization factor in the mismatched filter state, Representing the local mismatch filter coefficient vector corresponding to the mth transmit waveform, Is the mth discrete transmit waveform vector, Representing the M local mismatch filter coefficient vectors, Is to utilize the said The convolution matrix is constructed such that, Is the desired low sidelobe filter output response vector, Representation of The norm of the sample is calculated, Representation of Square of norm.
3. The radar communication integrated waveform based local mismatch filter design of claim 2, wherein the desired low sidelobe filter output response vector is an ideal impulse response with a main lobe position of 1 and a sidelobe region of 0.
4. The radar communication integrated waveform based local mismatch filter design according to claim 2, wherein the iterative solution to the optimization problem model using the alternate direction multiplier method outputs M local mismatch filter coefficient vectors, comprising: converting the optimization problem model into an equivalent form with equality constraints by using auxiliary variables so as to realize decoupling of the M local mismatch filter coefficient vectors; Introducing corresponding dual variables aiming at the equivalent form, and constructing an augmented Lagrangian function containing the dual variables; Alternately iteratively updating the filter coefficient vector, the auxiliary variable, and the dual variable to minimize the augmented lagrangian function; and stopping iteration when a preset convergence condition is met, and outputting the updated filter coefficient vectors as M local mismatch filter coefficient vectors.
5. The radar communication ensemble waveform based local mismatch filter design of claim 4, wherein the alternate iterative updating is performed in each iteration in the following order: 1) Fixing the auxiliary variable and the dual variable, and updating the filter coefficient vector; 2) Fixing the filter coefficient vector updated in the step 1) and the dual variable, and updating the auxiliary variable; 3) Fixing the filter coefficient vector updated in the steps 1) and 2) and the auxiliary variable, and updating the dual variable.
6. The radar communication integration waveform based local mismatch filter design of claim 4, wherein the preset convergence condition is: The iteration times reach a preset maximum value, or the original residual error is smaller than a first threshold value and the dual residual error is smaller than a second threshold value; Wherein the original residual is calculated according to an equality constraint in the equivalent form and the dual residual is calculated according to an iterative variation of the filter coefficient vector.

Description

Local mismatch filter design based on radar communication integrated waveform Technical Field The invention belongs to the technical field of radar systems and wireless communication, and particularly relates to a local mismatch filter design based on radar communication integrated waveforms. Background The integrated radar communication (IRAC) system can effectively relieve the increasingly tense spectrum conflict problem by sharing the hardware platform and the spectrum resource, and is beneficial to reducing the cost of the system in terms of size, weight and power consumption. Therefore, the IRAC technology has great application potential in the fields of the fifth generation and the future sixth generation mobile communication base stations, intelligent driving, unmanned aerial vehicle clusters and the like which have urgent demands for sensing and communication fusion. To improve the utilization of system resources, one core direction of research work is to design a transmit waveform that can carry both radar detection and wireless communication functions. However, IRAC systems face a unique technical challenge in practical applications, namely range sidelobe modulation (Range Sidelobe Modulation, RSM) problems. To increase the communication data rate, the IRAC transmit waveform will typically dynamically change with the communication information being transmitted. At the radar receiving end, in order to detect a moving object, a matched filtering process is generally performed on a received echo, and then, a hybrid wave cancellation is performed on a matched filtering output of continuous pulses through a moving object display (Moving Target Indication, MTI) and other technologies, so as to suppress stationary clutter and highlight the moving object. But due to the difference in transmit waveforms between different pulses, the respective matched filter outputs exhibit different range sidelobe structures, i.e., RSM phenomena. The inconsistency of the output structure can seriously damage the coherence relied on by the clutter cancellation process, so that the clutter suppression performance is obviously reduced, and the residual clutter energy after the MTI process is increased, thereby deteriorating the detection performance of a moving object. In order to mitigate the performance degradation caused by RSM within a coherent processing interval, researchers have proposed various approaches to design mismatched filters. Early Least-squares (LS) methods aimed at designing filters so that their output approximates as closely as possible the desired low sidelobe response to reduce the sidelobe level. To further improve the similarity between the outputs of the different filters, a Joint Least-squares (JLS) method is designed by iteratively approximating all the filter outputs to their average output. In order to suppress side lobes and ensure output similarity and simultaneously consider Signal-to-Noise Ratio loss, a combined weighted optimization (Joint Weighted Optimization, JWO) method is proposed, and the method seeks better comprehensive performance by performing weighted combined optimization on three targets of side lobe level, output similarity and Signal-to-Noise Ratio (SNR) loss. However, the above methods of LS, JLS, JWO, etc. are all designed as Global mismatch filters (Global MISMATCH FILTER, GMMF). GMMF is directed to the filter output over the entire transmit waveform pulse width range, failing to fully exploit design freedom to some extent. More importantly, under severe scenarios of low Signal-to-Clutter-plus-Noise Ratio (SCNR), the clutter cancellation performance of GMMF still has a large improvement room. Therefore, how to design a filter capable of more effectively suppressing RSM, and particularly capable of significantly improving clutter suppression and target detection performance under the condition of low SCNR is a technical problem to be solved in the art. Disclosure of Invention In order to solve the problems in the prior art, the invention provides a local mismatch filter design based on radar communication integrated waveforms. The technical problems to be solved by the invention are realized by the following technical scheme: The invention provides a local mismatch filter design based on radar communication integrated waveforms, which comprises the following steps: M discrete emission waveform vectors which are planned to be emitted by the radar communication integrated system in a coherent processing interval are obtained; Based on the M emission waveform vectors, constructing a weighted summation optimization problem model by taking a side lobe level of a minimized local mismatch filter output, similarity of filter outputs among different waveforms and signal-to-noise ratio loss as a joint optimization target; Carrying out iterative solution on the optimization problem model by adopting an alternate direction multiplier method, and outputting M partial mismatch filter coe