CN-121995380-A - Bistatic inverse synthetic aperture radar imaging calibration method based on GRFT-PSO algorithm

CN121995380ACN 121995380 ACN121995380 ACN 121995380ACN-121995380-A

Abstract

A bistatic inverse synthetic aperture radar imaging calibration method based on GRFT-PSO algorithm relates to the technical field of radar signal processing and radar imaging. The application aims to solve the problems of poor anti-interference capability and weak anti-noise performance of the existing bistatic inverse synthetic aperture radar imaging method in part of complex scenes. The method comprises the steps of carrying out pulse compression on echo data scattered on a target, estimating target motion parameters based on the echo data, constructing a compensation phase based on the estimated target motion parameters, optimizing the target motion parameters, substituting the compensation phase to compensate the echo data, estimating bistatic coefficients through linear fitting, carrying out direction dimensional compression on the compensated echo data based on the estimated bistatic coefficients, carrying out Fourier transformation on slow time to obtain a range-Doppler domain echo signal, and further obtaining a radar echo image.

Inventors

JIANG YICHENG
Gao Canfeng
WEI JIN
LI SIMING
GONG YU
ZHU XINHANG

Assignees

哈尔滨工业大学

Dates

Publication Date: 20260508
Application Date: 20260407

Claims (8)

1. The bistatic inverse synthetic aperture radar imaging calibration method based on the GRFT-PSO algorithm is characterized by comprising the following steps of: pulse compression is carried out on echo data scattered on the target, and echo data reflected by each scattering point on the target is obtained; Estimating target motion parameters based on the echo data, wherein the target motion parameters comprise distance, speed and acceleration; constructing a compensation phase based on the estimated target motion parameters; Optimizing the target motion parameters, substituting the optimal target motion parameters into the compensation phase, and further compensating the echo data; Estimating bistatic coefficients by linear fitting; Performing direction dimension compression on the compensated echo data based on the estimated bistatic coefficient; And carrying out Fourier transform on the echo data after the direction dimension compression on slow time to obtain a distance-Doppler domain echo signal, and further obtaining a radar echo image.
2. The imaging calibration method of bistatic inverse synthetic aperture radar based on GRFT-PSO algorithm according to claim 1, wherein the pulse compressing the echo data scattered on the target to obtain echo data reflected by each scattering point on the target comprises: Obtaining echo data reflected by each scattering point on the target according to : , Wherein, the For the bandwidth of the signal, Is a scattering point Is defined by the cross-sectional area of scattering, In order to observe the time period of the observation, As a function of the sine and the lattice, In order to be able to take a short time, In order to be a slow time period, As the carrier frequency of the signal, In units of imaginary numbers, In order to achieve the light velocity, the light beam is, Is a scattering point Is used for the purpose of determining the coordinates of (a), In order to be able to rotate the angular velocity effectively, A rectangular function is represented and is used to represent, Is the bistatic coefficient: , And The constant coefficients and the first order coefficients in the bistatic coefficients, respectively.
3. The GRFT-PSO algorithm-based bistatic inverse synthetic aperture radar imaging scaling method of claim 1, wherein the constructing a compensation phase based on estimated target motion parameters comprises: based on estimated target motion parameters Establishing a compensating phase : , Wherein, the In order to be a distance from each other, In order to be able to achieve a speed, In order for the acceleration to be a function of the acceleration, In order to be a slow time period, In order for the time-frequency to be fast, In order to achieve the light velocity, the light beam is, Is the equivalent instantaneous distance of the target.
4. The imaging calibration method of the bistatic inverse synthetic aperture radar based on the GRFT-PSO algorithm according to claim 1, wherein the optimizing the target motion parameter comprises: and taking the target motion parameters as particle positions, and optimizing the target motion parameters by adopting a particle swarm optimization algorithm.
5. The method for imaging calibration of bistatic inverse synthetic aperture radar based on GRFT-PSO algorithm of claim 1, wherein estimating bistatic coefficients by linear fitting comprises: By using 、 And (3) with Respectively representing the positions of the transmitter, receiver and target rotation center, And (3) with The connection line of (a) is expressed as , And (3) with The connection line of (a) is expressed as , And (3) with The connection line of (a) is expressed as Bistatic coefficient Is that And (3) with Is included in the plane of the first part; Obtaining with tracking device Pitch angle of (2) And azimuth angle A kind of electronic device Pitch angle of (2) And azimuth angle Then And (3) with Included angle of (2) Can be expressed as: , According to the geometric relationship, obtaining: , and the data obtained by the tracking equipment can be used for linearly fitting the bistatic coefficient Discrete values of (a); , Wherein, the And The constant coefficients and the first order coefficients in the bistatic coefficients, respectively.
6. The GRFT-PSO algorithm-based bistatic inverse synthetic aperture radar imaging scaling method of claim 1, wherein the performing direction-dimensional compression on the compensated echo data based on estimated bistatic coefficients comprises: and performing direction dimension compression on the compensated echo data according to the following steps: , Wherein, the For the echo data after the direction dimension compression, 、 And Is a phase coefficient, and has: , For the bandwidth of the signal, Is a scattering point Is defined by the cross-sectional area of scattering, In order to observe the time period of the observation, As a function of the sine and the lattice, In order to be able to take a short time, In order to be a slow time period, As the carrier frequency of the signal, In units of imaginary numbers, In order to achieve the light velocity, the light beam is, Is a scattering point Is used for the purpose of determining the coordinates of (a), A rectangular function is represented and is used to represent, And The constant coefficients and the first order coefficients in the bistatic coefficients respectively, Is an effective rotational angular velocity.
7. The imaging calibration method of bistatic inverse synthetic aperture radar based on GRFT-PSO algorithm of claim 6, wherein fourier transforming the echo data after the direction dimension compression to slow time to obtain a range-doppler domain echo signal, further obtaining a radar echo image, comprises: Echo data after compressing the direction dimension according to the following For slow time Fourier transforming to obtain a range-Doppler domain echo signal : , Wherein, the In order to be able to take a short time, As the coordinates of the scattering point with respect to the center of rotation, As a function of the wavelength(s), Is Doppler frequency; Will be And Substituting the range-doppler domain echo signal Expression, obtaining radar echo image : , Wherein, the For the distance-dimensional resolution, For the resolution of the dimension of the direction, As the coordinates of the distance dimension, Is the coordinates of the direction dimension.
8. The method for imaging calibration of bistatic inverse synthetic aperture radar based on GRFT-PSO algorithm according to claim 6, wherein the effective rotational angular velocity The method comprises the following steps: , Intermediate variable 。

Description

Bistatic inverse synthetic aperture radar imaging calibration method based on GRFT-PSO algorithm Technical Field The application belongs to the technical field of radar signal processing and radar imaging. Background Inverse Synthetic Aperture Radar (ISAR) can image targets all day long and all weather long distance, thus obtaining the form and structure information of the targets. Early ISARs employed a single base system, i.e., the transmitter and receiver were co-located. Single-base ISAR is not effective for imaging when objects are moving along a radar line of sight (LOS). To solve this problem, a bistatic radar system (Bi-ISAR) has been proposed, i.e. a mode in which the transmitter and receiver are spatially separated. In addition, the Bi-ISAR has a special bistatic configuration, so that the Bi-ISAR has remarkable effects on acquiring a target high-precision high-resolution image, anti-stealth and anti-interference. With the development of electronic interference and anti-reconnaissance technology, higher requirements are put forward on the concealment, anti-interference capability, imaging precision and target stealth detection of radar imaging. Wherein, a novel star-transmitting-receiving double-base ISAR system is proposed and researched. The system adopts the existing spaceborne SAR (synthetic aperture radar) as a transmitter and the ground-based radar as a receiver. The spaceborne SAR is far away from the ground, can effectively emit electromagnetic waves, and realizes long-distance imaging. Meanwhile, the receiver passively receives the target echo signals, so that the risk of being interfered is reduced. In addition, the system has a complex geometric configuration, can obtain multidimensional information of the target, and is beneficial to improving the accuracy of target identification. To obtain a high resolution image, a large rotation angle to the target is required. However, the large rotation angle can cause migration (RCM) of a distance unit, under the system, the bistatic factor and the effective rotation speed are time-varying, and the bistatic factor and the effective rotation speed are seriously coupled, so that the problems of cross distance scale distortion, image distortion, defocusing effect and the like are generated. Therefore, the core of the bistatic inverse synthetic aperture radar imaging calibration method is that non-cooperative target motion parameters are estimated by utilizing parameter estimation, phase information is extracted, and time-varying bistatic factors and rotation speeds are solved. M. Martorella et al, in the document "On Bistatic INVERSE SYNTHETIC Aperture Radar" (for bistatic inverse synthetic Aperture Radar) for the first time, proposed the concept of Bistatic Equivalent Monostatic (BEM), proving the feasibility of applying classical monostatic ISAR processing frameworks to bistatic configurations, but with the drawbacks of poor transmitter flexibility and inability to adapt to complex application scenarios. B. S. Kang et al propose Bi-ISAR calibration algorithm for uniform and effective rotation speed at Bistatic-ISAR Cross-RANGE SCALING, select specific scatterers through distance units to obtain phase coefficients, and apply particle swarm optimization algorithm to effectively estimate rotation angular velocity and bistatic coefficients to optimize rotation compensation, but cannot solve the problem of weak anti-noise performance. Disclosure of Invention The application aims to solve the problems of poor anti-interference capability and weak anti-noise performance of the existing bistatic inverse synthetic aperture radar imaging method in part of complex scenes, and provides a bistatic inverse synthetic aperture radar imaging calibration method based on a GRFT-PSO algorithm. The application provides a bistatic inverse synthetic aperture radar imaging calibration method based on a GRFT-PSO algorithm, which comprises the following steps: pulse compression is carried out on echo data scattered on the target, and echo data reflected by each scattering point on the target is obtained; Estimating target motion parameters based on the echo data, wherein the target motion parameters comprise distance, speed and acceleration; constructing a compensation phase based on the estimated target motion parameters; Optimizing the target motion parameters, substituting the optimal target motion parameters into the compensation phase, and further compensating the echo data; Estimating bistatic coefficients by linear fitting; Performing direction dimension compression on the compensated echo data based on the estimated bistatic coefficient; And carrying out Fourier transform on the echo data after the direction dimension compression on slow time to obtain a distance-Doppler domain echo signal, and further obtaining a radar echo image. In one possible design, the pulse compressing the echo data scattered on the target to obtain echo data reflected by each scattering p