CN-120847754-B - Experimental system for jointly and synchronously measuring micro Doppler and polarization characteristics of space target laser

CN120847754BCN 120847754 BCN120847754 BCN 120847754BCN-120847754-B

Abstract

The invention discloses an experimental system for jointly and synchronously measuring the micro Doppler and polarization characteristics of a space target laser, which comprises a light source module and a micro Doppler-polarization module, wherein the light source module emits light to realize energy distribution of four channels and the like through an optical fiber beam splitter after energy beam splitting is carried out on the light emitted by the light source module through the optical fiber beam splitter, the micro Doppler-polarization module adopts a coherent detection architecture to carry out heterodyne mixing on four paths of local oscillation light and echo light of a corresponding polarization state respectively, the intensity of each polarization component in the echo light is measured in real time, micro Doppler frequency shift of the target motion is obtained at the same time, the attitude angle and the depolarization degree of the target are calculated through an algorithm, and an incidence attitude-depolarization degree mapping database is established for collecting the depolarization degrees of different materials and various incidence attitude angles, so that new dimensions can be provided for unknown space target detection, and the space target detection technology is promoted to develop to a more refined and intelligent direction.

Inventors

YANG ZHEN
Gui Kaiyuan
ZHANG YONG
ZHANG JIANLONG
JIAO DAN
QU XINLEI
DAI XIN

Assignees

哈尔滨工业大学

Dates

Publication Date: 20260508
Application Date: 20250708

Claims (6)

1. The experimental system for jointly and synchronously measuring the micro Doppler and polarization characteristics of the space target laser is characterized by comprising a light source module, a micro Doppler-polarization module and an upper computer, wherein: The emitted light of the light source module is subjected to energy beam splitting through a 1:9 optical fiber beam splitter, and after local oscillation light with the energy ratio of 10% is introduced into 80MHz fundamental frequency modulation through an acousto-optic modulator, four-channel equal energy distribution is realized through the 1:1:1:1 optical fiber beam splitter and is marked as local oscillation light 1, local oscillation light 2, local oscillation light 3 and local oscillation light 4; The micro Doppler-polarization module adopts two paths of polarization beam splitters to decouple echo light into four paths of linear polarized light with the energy and polarization states of 0 degree, 90 degrees, 45 degrees and 135 degrees respectively, and the linear polarized light is marked as echo light 1, echo light 2, echo light 3 and echo light 4; the micro Doppler-polarization module adopts a coherent detection architecture, four paths of local oscillation light and echo light in a corresponding polarization state are subjected to heterodyne mixing respectively, after photoelectric conversion is completed by a photoelectric detector, real-time signal acquisition is realized through a high-speed data acquisition card, and the high-speed data acquisition card transmits acquired signals to an upper computer; After 4 paths of mixed signals are obtained, the upper computer calculates the energy corresponding to each polarization state, so that the depolarization degree of the target echo light is obtained, meanwhile, the 4 paths of mixed signals are regarded as 4 paths of laser micro Doppler signals, then, through digital filtering, time-frequency analysis and parameter resolving steps, the incident attitude angle of the target is obtained, synchronous real-time measurement of the micro Doppler and polarization characteristics of the target is realized, on the basis, statistical analysis is carried out on the depolarization degrees collected under different materials and multiple incident attitude angles, and an incident attitude angle-depolarization degree mapping database is established, so that joint application of the micro Doppler and polarization characteristics in the field of space target detection and identification is realized.
2. The experimental system for jointly and synchronously measuring the micro Doppler and polarization characteristics of the space target laser according to claim 1, wherein the light source module adopts a fiber laser with the wavelength of 1064nm, transmits polarized light with the power of 100mW, and has the spot diameter of 2cm after collimation.
3. The experimental system for the joint simultaneous measurement of laser micro-doppler and polarization properties of a spatial target according to claim 1, wherein the target comprises a natural biological material and an artificial composite material.
4. The experimental system for jointly and synchronously measuring the micro-Doppler and polarization characteristics of the space target laser according to claim 3, wherein the natural biological material is a bird feather, and the artificial composite material is a composite material for the space target, paper or board.
5. The experimental system for jointly and synchronously measuring micro-doppler and polarization characteristics of a spatial target laser according to claim 1, wherein the depolarization degree D is expressed as: Where P is the degree of polarization, S 0 is the total light intensity of the light wave, S 1 is the difference in the intensity of linearly polarized light in the x and y directions, and S 2 is the difference in the intensity of linearly polarized light in the 45 DEG and 135 DEG directions.
6. The experimental system for jointly and synchronously measuring the micro-Doppler and polarization characteristics of a space target laser according to claim 1, characterized in that the incident attitude angle The extraction formula of (2) is: in the formula, Is the distance from the top to the center of the bottom of the cube object, , For a cubic target side length, f max is the micro-doppler maximum frequency shift, In order to emit the laser wavelength, Is a known target spin frequency.

Description

Experimental system for jointly and synchronously measuring micro Doppler and polarization characteristics of space target laser Technical Field The invention belongs to the field of laser radar application, and relates to an experimental system for measuring laser micro Doppler and polarization characteristics of a space target. Background With the increasing number of human aerospace activities, the number and variety of space objects is increasingly rich, including normal objects such as satellites, spacecraft, debris, and explosive fragments, and uncontrolled objects. How to realize high-precision and real-time detection of various space targets becomes an important subject in the development of the current aerospace technology. The optical polarization characteristic is a basic physical quantity of interaction of light and a substance, and can reflect differences in optical constants, surface roughness, coating characteristics, and the like of a target material. Therefore, by utilizing the polarization characteristics of the target, new dimensions of detection, classification and identification of the space target can be increased. The detection technology based on the laser micro Doppler effect is widely applied to measurement of space target motion and geometric parameters by virtue of the advantages of high resolution, high detection sensitivity and the like. The attitude angle is a key parameter for describing the spatial orientation of the target, and not only determines the angle of polarized light incident on the surface of the target, but also influences the change of the polarization characteristic of echo light. By accurately estimating the attitude angle of the target, the contribution of the inherent attribute of the material to the depolarization characteristic is separated, so that the rule of the incident attitude angle-depolarization degree of different materials is obtained, a new method is provided for accurate resolution and identification of the space target, and the accuracy of the detection technology is improved. In the prior art, the micro-doppler and polarization measurements are usually performed independently in a time-sharing manner. The method has two defects that on one hand, micro Doppler and polarization parameters are acquired at different time points by time-sharing measurement, physical states of the same observation condition cannot be aligned accurately, rapid detection and accurate response of a target in a high-speed motion state are not facilitated, and on the other hand, the target cannot be detected and identified more comprehensively and accurately by independently applying one of the micro Doppler effect or the polarization characteristic, so that the reliability of target detection and identification is reduced. Disclosure of Invention In order to solve the problems in the background art, the invention provides an experimental system for jointly and synchronously measuring the micro Doppler and polarization characteristics of a space target laser, which measures the intensity of each polarization component in return light in real time, obtains the micro Doppler frequency shift of the target motion, calculates the attitude angle and the depolarization degree of the target through an algorithm, performs statistical analysis on the depolarization degrees acquired under different materials and various incident attitude angles, establishes a mapping database of the incident attitude degree and the depolarization degree, can provide new dimension for unknown space target detection, and promotes the space target detection technology to develop to a more refined and intelligent direction. The invention aims at realizing the following technical scheme: an experimental system for jointly and synchronously measuring the micro Doppler and polarization characteristics of a space target laser comprises a light source module, a micro Doppler-polarization module and an upper computer, wherein: The emitted light of the light source module is subjected to energy beam splitting through a 1:9 optical fiber beam splitter, and after local oscillation light with the energy ratio of 10% is introduced into 80MHz fundamental frequency modulation through an acousto-optic modulator, four-channel equal energy distribution is realized through the 1:1:1:1 optical fiber beam splitter and is marked as local oscillation light 1, local oscillation light 2, local oscillation light 3 and local oscillation light 4; The micro Doppler-polarization module adopts two paths of polarization beam splitters to decouple echo light into four paths of linear polarized light with the energy and polarization states of 0 degree, 90 degrees, 45 degrees and 135 degrees respectively, and the linear polarized light is marked as echo light 1, echo light 2, echo light 3 and echo light 4; the micro Doppler-polarization module adopts a coherent detection architecture, four paths of local oscillation light and echo li