In-Orbit Calibration Method of Beam Pointing Consistency for Distributed InSAR Satellites

In this paper, an in-Orbit calibration method of satellite beam pointing consistency of distributed interferometric synthetic aperture radar (InSAR) is proposed, which can be used in the design of distributed InSAR binary SAR system. During the in-orbit operation of distributed InSAR satellites, due to the inconsistency of dual satellite SAR beam direction and transceiver status, the working temperature environment of dual satellite SAR is inconsistent, resulting in the deviation of dual satellite SAR beam direction and the decrease of slave satellite receiving power, which leads to the problem of poor coherence of dual spaceborne SAR echo data. The implementation of this method is divided into two parts: "rough adjustment" and "fine adjustment". It can calibrate the beam pointing consistency of distributed InSAR satellites in orbit, effectively improve the coherence of dual images, and thus improve the mapping quality/accuracy of satellite system.

I. Introduction

Distributed InSAR satellites are the important remote sensing means to obtain high-precision digital elevation model (DEM). It uses two SAR antennas distributed along the vertical course to observe the same area from different angles, and performs interferomeric processing on the two complex SAR images obtained to obtain the skew distance difference between the phase center of the primary and secondary radar antennas and the target, and then obtains the DEM of the observation area. The distributed satellite InSAR system with two SAR on two satellites flying in formation to observe the earth at the same time. It can overcome the problems of time decoherence and low baseline accuracy faced by repeated navigation InSAR, and can obtain high-precision DEM.