CN-122017819-A - High-orbit double-base radar air target detection method based on multidimensional manifold constraint

CN122017819ACN 122017819 ACN122017819 ACN 122017819ACN-122017819-A

Abstract

The invention provides a multi-dimensional manifold constraint-based high-orbit double-base radar aerial target detection method, which relates to the technical field of double-base radar target detection and comprises the following steps of calculating the ground coverage area of a high-orbit satellite irradiation source; the method comprises the steps of establishing an echo signal model, dividing an echo signal with a long observation period into a plurality of short time subframes, ensuring that Doppler walk of a target in each subframe time is limited in a single resolution unit, estimating Doppler center frequency and Doppler change rate of the target in each subframe, performing walk correction and high-order motion phase compensation of a distance-crossing unit in the subframe, realizing coherent energy focusing in the subframe, and performing incoherent accumulation on target energy of a cross-frame to obtain detection statistics. The method of the invention balances the coherent gain and the compensation complexity through the framing strategy, reduces the operand by utilizing the cross-frame parameter evolution constraint, and can realize the steady detection of the long-distance weak maneuvering target.

Inventors

SUN ZHICHAO
YANG JIANYU
HOU YANG
LI YI
YANG FAN
WANG YU
KUANG HUI
MAO YONGFEI
JIANG WEN
WU JUNJIE

Assignees

电子科技大学
中国空间技术研究院

Dates

Publication Date: 20260512
Application Date: 20260318

Claims (10)

1. The high-orbit double-base radar air target detection method based on multidimensional manifold constraint is characterized by comprising the following steps of: s1, calculating the ground coverage area of a high orbit satellite irradiation source, and determining the geometric layout of a radar network and the geometric resolution performance of an observation area by combining the observation requirement; S2, combining the double-base distance histories of the high orbit satellite and the receiving platform, establishing an echo signal model of the aerial high maneuvering target under the double-base system and analyzing the echo characteristics of the echo signal model; Step S3, dividing echo signals of a long observation period into a plurality of short time subframes according to the system distance resolution and the Doppler resolution, and ensuring that Doppler walk of a target in each subframe time is limited in a single resolution unit; S4, aiming at the problems of weaker migration and target echo caused by high maneuver, modeling and optimizing, adopting a multidimensional parameter space manifold constraint strategy to improve a particle swarm optimization method, and estimating Doppler center frequency and Doppler change rate of targets in each subframe; S5, performing range-over unit walking correction and higher-order motion phase compensation in the subframe by utilizing the parameters estimated in the step S4, and realizing coherent energy focusing in the subframe by means of de-slope Fourier transformation; And S6, extracting the characteristics of each subframe in a distance-Doppler domain, and carrying out incoherent accumulation on target energy of a cross frame to obtain detection statistics.
2. The method for detecting an airborne target of a high orbit bistatic radar based on the constraint of multidimensional manifold according to claim 1, wherein in said step S1, the calculation of the ground coverage area of the high orbit satellite irradiation source specifically comprises: Establishing a relation between a satellite visual angle and a geocentric angle by utilizing a sine theorem, respectively calculating a distance coverage width and a azimuth coverage width, and defining an effective irradiation area by combining an elliptic area formula; wherein the distance is toward the coverage width The azimuth coverage width is obtained by calculating the arc length difference from the edge point of the coverage area to the point under the satellite According to the pitch And azimuth beam width Calculated as The final coverage area S is calculated as 。
3. The method for detecting an airborne target of a high orbit bistatic radar based on multidimensional manifold constraints according to claim 1, wherein in the step S2, the method for establishing an echo signal model of an airborne high maneuvering target under a bistatic system specifically comprises: Dual-base range history between target and high-orbit satellite and receiving platform At slow time The process performs a second-order Taylor series expansion, expressed as In which, in the process, Indicating at slow time Where the dual-base distance between the target and the high-orbit satellite and receiving platform, To at slow time Where the dual-base distance between the target and the high-orbit satellite and receiving platform, Is slow time The first derivative of the position is shown, Representing a slow time variable, describing the time offset in the slow time dimension, Is a high-order infinitesimal term of Taylor expansion.
4. The multi-dimensional manifold constraint-based high-orbit bistatic radar airborne target detection method according to claim 3, wherein in said step S3, the criteria for dividing the short-time subframes are: and ensuring that the residual distance error caused by the second-order Taylor expansion is smaller than a system distance resolution unit and the Doppler frequency shift residual error is smaller than 1/3 of the system Doppler frequency resolution within the preset subframe duration.
5. The method for detecting an air target of a high-orbit bistatic radar based on the multidimensional manifold constraint according to claim 1, wherein in the step S4, the multidimensional parameter space manifold constraint strategy specifically comprises: dividing the full observation period into n subframes, and dividing the original independent 2n motion parameters to be solved, namely Doppler center frequency of each subframe And Doppler rate of change And carrying out joint estimation by projecting the multi-dimensional parameter space popularity constraint to a constraint subspace with the dimension of n+2.
6. The method for detecting the aerial target of the high-orbit double-base radar based on the multidimensional manifold constraint according to claim 1 or 5, wherein in the step S5, a phase compensation operator is constructed by using a resident phase principle, linear and higher-order range migration is eliminated in a subframe, and spectral line broadening caused by doppler frequency variation is eliminated by using a de-slope fourier transform, wherein the expression of the de-slope fourier transform is: In the formula (I), in the formula (II), Indicating that in the nth subframe, the distance is R and the Doppler frequency is Is used to process the signal after the de-slope processing, Indicating that in the nth subframe, the distance is R and the slow time is Is used to determine the original echo signal of the (c), Representing an exponential function, for constructing a kernel function of fourier transform and phase compensation, In units of imaginary numbers, In order to be a doppler frequency, In order to be a slow time period, Is the rate of change of the doppler frequency in the nth subframe.
7. The method for detecting an air target of a high-orbit bistatic radar based on the multi-dimensional manifold constraint according to claim 6, wherein in the step S5, after intra-frame phase accumulation, the signal expression of the nth subframe in the range-doppler domain is: In the formula (I), in the formula (II), For the target echo signal amplitude, Is a rectangular window function, used to represent the effective duration or frequency range of the signal in the doppler domain, And In the nth sub-frame, the Doppler central frequency estimated value and Doppler frequency slope estimated value of the target are respectively, For the duration of the sub-frame, Is a distance pulse compression function, and is used for describing the characteristics of a main lobe and a side lobe of a signal in a distance domain, For the initial slant distance of the object, For the wavelength of the radar signal, And The Doppler center frequency estimation value and the Doppler frequency change rate estimation value of the target are respectively obtained in the whole frame, The distance phase offset term of the target is in the nth subframe.
8. The method for detecting the target in the air of the high-orbit bistatic radar based on the multidimensional manifold constraint according to claim 7, wherein in the step S6, performing incoherent accumulation on the target energy across frames specifically comprises: taking the accumulation result of the intermediate reference subframes as a benchmark, performing motion track compensation on the energy peak position of each subframe in the distance-Doppler domain, and accumulating to obtain final detection statistics The expression is: In the formula (I), in the formula (II), Representing summing all subframes n, and modulo the signal, representing a cross-frame incoherent accumulation operation, for improving the signal-to-noise ratio of the target energy, Representing the signal amplitude of the nth subframe in the range-doppler domain.
9. The method for detecting the aerial target of the high-orbit bistatic radar based on the multidimensional manifold constraint according to claim 7, wherein in the step S6, the echo is shifted by using the mathematical mapping relation between the range migration and the doppler parameter of the target echo, so as to realize the accumulation between echo frames.
10. A computer readable storage medium having stored thereon a computer program, which when executed by a processor is capable of implementing the steps of the multi-dimensional manifold constraint based high-orbit bistatic radar airborne target detection method according to any one of claims 1-9.

Description

High-orbit double-base radar air target detection method based on multidimensional manifold constraint Technical Field The invention relates to the technical field of double-base radar target detection, in particular to a high-orbit double-base radar air target detection method based on multidimensional manifold constraint. Background With the rapid development of an aerospace integrated information network, bistatic radars based on high-orbit satellite irradiation sources show important potential in the field of long-distance wide-area airborne target detection. However, the high-orbit bistatic radar faces the dual challenges of extremely weak target echo signals and high target maneuverability in practical applications. The existing detection method is mainly divided into two types, namely a detection method based on a low-order motion model, such as a Keystone conversion is used for correcting linear range migration of a uniform-speed target, but when the target has high mobility, the target is difficult to accurately compensate high-order phase errors, so that energy cannot be effectively focused, and a high-order motion matching method based on long-time coherent accumulation, such as a generalized Radon-Fourier conversion, is needed to perform grid search on an unknown high-dimensional parameter space, and has extremely high calculation complexity, so that real-time processing requirements are difficult to meet. The prior art scheme has the remarkable defects that the method based on the low-order model is difficult to adapt to a high maneuvering target, so that signal energy is seriously dispersed in long coherence time, the detection performance is rapidly reduced, and the method based on the high-order model matching can realize accurate focusing theoretically, but the huge parameter search space brings exponentially increased calculation burden, is easy to sink into local optimum, and has poor engineering practicability. Therefore, how to significantly reduce the complexity and the calculated amount of parameter estimation while ensuring the effective focusing on a high maneuvering weak target becomes a key technical problem to be solved in the field of high-orbit bistatic radars. Disclosure of Invention Aiming at the problems that under a high-orbit bistatic radar system, an aerial target moves seriously by a distance unit (RCM) and Doppler frequency shift movement in long coherent time due to high mobility, a conventional detection means is invalid due to extremely weak target signals, and the multi-dimensional parameter searching calculation complexity is high, the invention provides a high-orbit bistatic radar aerial target detection method based on multi-dimensional manifold constraint. The invention aims to balance coherent gain and compensation complexity through a framing strategy, reduce operand by utilizing cross-frame parameter evolution constraint and realize stable detection of a long-distance weak maneuvering target. In order to achieve the above purpose, the technical scheme adopted by the invention comprises the following steps: according to a first aspect of the invention, there is provided a high-orbit bistatic radar aerial target detection method based on multidimensional manifold constraints, comprising: s1, calculating the ground coverage area of a high orbit satellite irradiation source, and determining the geometric layout of a radar network and the geometric resolution performance of an observation area by combining the observation requirement; S2, combining the double-base distance histories of the high orbit satellite and the receiving platform, establishing an echo signal model of the aerial high maneuvering target under the double-base system and analyzing the echo characteristics of the echo signal model; Step S3, dividing echo signals of a long observation period into a plurality of short time subframes according to the system distance resolution and the Doppler resolution, and ensuring that Doppler walk of a target in each subframe time is limited in a single resolution unit; S4, aiming at the problems of weaker migration and target echo caused by high maneuver, modeling and optimizing, adopting a multidimensional parameter space manifold constraint strategy to improve a particle swarm optimization method, and estimating Doppler center frequency and Doppler change rate of targets in each subframe; S5, performing range-over unit walking correction and higher-order motion phase compensation in the subframe by utilizing the parameters estimated in the step S4, and realizing coherent energy focusing in the subframe by means of de-slope Fourier transformation; And S6, extracting the characteristics of each subframe in a distance-Doppler domain, and carrying out incoherent accumulation on target energy of a cross frame to obtain detection statistics. Optionally, in the step S1, the calculating the ground coverage area of the high orbit satellite irradiation source specific