CN-122017838-A - Distributed InSAR satellite range-to-space synchronous on-orbit test method and system

CN122017838ACN 122017838 ACN122017838 ACN 122017838ACN-122017838-A

Abstract

The invention provides a distributed InSAR satellite distance-to-space synchronous on-orbit test method and system, which comprise the steps of acquiring echo data of the same area of a tropical rain forest by adopting a single-generation and double-reception mode, respectively imaging main satellite and auxiliary satellite tropical rain forest SAR echoes to acquire main satellite SAR images, acquiring a main satellite distance-to-beam pointing test result RP02, an auxiliary satellite distance-to-beam pointing test result RP12, a main satellite ground test stage distance-to-pointing test result RP01, an auxiliary satellite ground test stage distance-to-pointing test result RP11, judging whether I RP01-RP 02I and I RP11-RP 12I exceed a threshold, selecting test sample pairs simultaneously within the threshold range, calculating distance-to-space synchronous test results, calculating a plurality of groups of test sample results, averaging calculated values of each group, further reducing random errors, and acquiring a final test result.

Inventors

HOU YUSHENG
LU RUIFENG
ZHAO DI
HE KUN
LIU YEFENG
LIU YANYANG

Assignees

上海卫星工程研究所

Dates

Publication Date: 20260512
Application Date: 20260213

Claims (10)

1. The method for testing the distance-to-space synchronization of the distributed InSAR satellites is characterized by comprising the following steps of: Step1, a double satellite adopts a single-transmitting double-receiving working mode to acquire radar echo data of the same ground target area, wherein the single-transmitting double-receiving working mode is that a main satellite transmits radar wave signals to the ground target area, and the main satellite and an auxiliary satellite simultaneously receive radar echo signals from the same ground target area; Step 2, respectively carrying out imaging processing on radar echo data received by a main satellite and an auxiliary satellite to obtain a main satellite SAR image and an auxiliary satellite SAR image; step 3, based on the main star SAR image and the auxiliary star SAR image, respectively obtaining a main star in-orbit radial beam pointing test result RP02 and an auxiliary star in-orbit radial beam pointing test result RP12; step 4, obtaining a distance direction test result RP01 obtained by the main star in the ground test stage and a distance direction test result RP11 obtained by the auxiliary star in the ground test stage; Step 5, based on RP01, RP02, RP11 and RP12, judging and screening the validity of the test sample; Step 6, calculating to obtain a distance-to-space synchronous test result of the distributed InSAR satellite double-star system based on the screened effective test sample data; And 7, calculating a plurality of groups of test sample results, averaging the calculated values of each group, further reducing random errors, and obtaining a final test result.
2. The method for spatially synchronizing the distance directions of the distributed InSAR satellites in orbit according to claim 1, wherein the step 3 comprises the steps of adopting a method of taking a modulus average along the azimuth direction to the acquired SAR image, counting average power values along the distance directions, and fitting a pattern curve to acquire an SAR distance direction pattern in-orbit test result, wherein the highest gain point of a main star pattern is a distance beam pointing test result RP02, and the highest gain point of an auxiliary star pattern is a distance beam pointing test result RP12.
3. The method for spatially synchronizing the range of the distributed InSAR satellites in the on-orbit according to claim 1, wherein in the step 4, RP01 is the ground test range direction obtained by obtaining the measured data of the SAR antenna pattern by the main satellite in the ground darkroom test stage and calculating the measured data, and RP11 is the ground test range direction obtained by obtaining the measured data of the SAR antenna pattern by the auxiliary satellite in the ground darkroom test stage and calculating the measured data.
4. The method for spatially synchronizing the range-wise and on-orbit testing of the distributed InSAR satellite according to claim 1, wherein said step 5 comprises: judging whether the I RP01-RP 02I and the I RP11-RP 12I exceed a preset threshold, and selecting a test sample pair of which the I RP01-RP 02I and the I RP11-RP 12I are simultaneously in the preset threshold range.
5. The method for testing the distance to the spatial synchronization of the distributed InSAR satellites according to claim 1, wherein in the step 6, the result of the distance to the spatial synchronization is obtained by calculating the formula |rp12-rp02|/rw×100%, wherein RW is the dominant satellite distance to beam width.
6. A distributed InSAR satellite range to space synchronous on-orbit test system, comprising: The module M1 is used for acquiring radar echo data of the same ground target area by using a single-transmitting double-receiving working mode, wherein the single-transmitting double-receiving working mode is used for transmitting radar wave signals to the ground target area by a main satellite, and the main satellite and an auxiliary satellite simultaneously receive the radar echo signals from the same ground target area; The module M2 is used for respectively carrying out imaging processing on radar echo data received by the main satellite and the auxiliary satellite to obtain a main satellite SAR image and an auxiliary satellite SAR image; The module M3 is used for respectively acquiring a main star in-orbit distance beam pointing test result RP02 and an auxiliary star in-orbit distance beam pointing test result RP12 based on the main star SAR image and the auxiliary star SAR image; the module M4 is used for acquiring a distance directional test result RP01 obtained by the main star in the ground test stage and a distance directional test result RP11 obtained by the auxiliary star in the ground test stage; module M5, based on RP01, RP02, RP11 and RP12, judging and screening the validity of the test sample; A module M6, based on the screened effective test sample data, calculating to obtain a distance-to-space synchronous test result of the distributed InSAR satellite double-star system; And the module M7 is used for calculating a plurality of groups of test sample results, averaging the calculated values of each group, further reducing random errors and obtaining a final test result.
7. The distributed InSAR satellite range-wise spatial synchronization on-orbit testing system according to claim 6, wherein the module M3 comprises the steps of adopting a method of taking a modulus average along the azimuth direction on the acquired SAR image, counting average power values along the range direction, and fitting a pattern curve to acquire an SAR range-wise pattern on-orbit test result, wherein the maximum point of the gain of the main star pattern is a range-wise beam pointing test result RP02, and the maximum point of the gain of the auxiliary star pattern is a range-wise beam pointing test result RP12.
8. The system for spatially synchronizing the range of distributed InSAR satellites in orbit according to claim 6, wherein in the module M4, RP01 is the ground test range direction obtained by acquiring the SAR antenna pattern actual measurement data and calculating the SAR antenna pattern actual measurement data of the main satellite in the ground darkroom test phase, and RP11 is the ground test range direction obtained by acquiring the SAR antenna pattern actual measurement data and calculating the SAR antenna pattern actual measurement data of the auxiliary satellite in the ground darkroom test phase.
9. The distributed InSAR satellite distance to space synchronization on-orbit test system according to claim 6, wherein the module M5 comprises determining if |rp01-rp02|, |rp11-rp12| exceeds a preset threshold, selecting a pair of test samples having |rp01-rp02|, |rp11-rp12|, and being within the preset threshold simultaneously.
10. The distributed InSAR satellite distance to space synchronization on-orbit test system according to claim 6, wherein the distance to space synchronization test result is obtained by calculation of the formula |rp12-rp02|/RW x 100%, where RW is the dominant satellite distance to beam width, in the module M6.

Description

Distributed InSAR satellite range-to-space synchronous on-orbit test method and system Technical Field The invention relates to the technical field of aerospace systems, in particular to a distributed InSAR satellite distance-to-space synchronous on-orbit test method and system. Background Interferometric synthetic aperture radar (InSAR) is an important remote sensing means for obtaining high-precision ground elevation models (DSMs). The method comprises the steps of observing the same area with different visual angles by using two SAR antennas distributed along a vertical course, carrying out interference processing on two obtained complex SAR images, solving the skew difference between the phase center of a main radar antenna and a target and further obtaining the DSM of an observation area. The distributed satellite InSAR system installs two SAR on two satellites in formation flight for simultaneous earth observation, can overcome the problems of time decoherence, low baseline precision and the like faced by repeated navigation InSAR, and can acquire high-precision DSM. Because the SAR transmitting antenna and the receiving antenna are arranged on different satellite platforms, to realize single-satellite SAR imaging and InSAR interferometry, the receiving and transmitting antenna beams must cover the same ground irradiation area at the same time, so that the space synchronization of the double-satellite SAR beams is realized, and the auxiliary satellite can receive enough echo energy and maintain good coherence with the main satellite. Patent application document CN112327262A discloses an on-orbit calibration method and system for the directional consistency of distributed InSAR satellite SAR beams, solves the problem of on-orbit calibration of the directional consistency of double stars in a self-receiving mode, and adopts the double stars-transmitting-receiving mode to carry out the on-orbit test of distance-to-space synchronization, wherein the application direction and the technical approach of the two methods are obviously different. Patent application document CN112346028A discloses a method and a system for on-orbit testing of the azimuth space synchronization of a distributed InSAR satellite, which solve the problem of on-orbit testing of the double-star azimuth beam pointing in a self-receiving mode of the distributed InSAR satellite system, and the method adopts the double-star-transmitting double-receiving mode to carry out the on-orbit testing of the distance space synchronization, and the application direction and the technical approach of the method and the system are obviously different. Patent application document CN119087368A discloses a satellite-borne SAR beam pointing high-precision quick calibration method based on echo data, solves the calibration problem of single-star system SAR beam pointing, and adopts a double-star-transmission double-reception mode to carry out distance-to-space synchronous on-orbit test, wherein the application direction, the application range and the technical approach of the method are obviously different. Patent application document CN119644269A discloses a satellite-borne SAR beam pointing calibration method based on antenna installation deviation and poor beam image characteristics, solves the calibration problem that a single star system adopts SAR beam pointing, and adopts a double-star one-transmitter double-receiver mode to carry out distance-to-space synchronous on-orbit test, wherein the application direction, the application range and the technical approach of the method are all obviously different. Based on the analysis of the influence of satellite formation InSAR spatial synchronization on system performance, university of Wuhan university report (information science edition), 200710. The method mainly solves the problem of the on-orbit testing method of the distance-to-space synchronization under the one-generation two-reception mode of the distributed InSAR double-star system, and the paper mainly demonstrates the requirement of the InSAR elevation measurement on the space synchronization under the formation condition and analyzes the influence of the space synchronization on the elevation measurement precision and the resolution of the InSAR system, and has obvious differences in application direction, application range and technical approach. An interference SAR satellite formation beam synchronization method, china space science and technology, 201005. The method mainly solves the problem of the method for testing the distance-to-space synchronization in the one-shot and two-shot mode of the distributed InSAR double-star system, and the paper mainly provides an engineering realization way for completing beam synchronization through satellite formation attitude guidance, and the application direction, the application range and the technical way are all obviously different. A practical satellite-machine bistatic SAR space synchronization me