A New 2D Doppler Steering Method For Beam Synchronization In Format Flying Satellites InSAR Systems

Abstract

As we know that beam synchronization is a key technology for format flying satellites InSAR (interferometric synthetic aperture radar) system. Also, the Doppler Center Frequency is a very important parameter for spaceborne SAR signal processing. The more decrease of residual Doppler Center Frequency, the more convenience to SAR image formation. In this paper, the expression of Doppler Center Frequency is given after the analysis of the geometry of spaceborne SAR imaging. It considered the elliptical orbit and the pitch steering angle. For the sake of minimizing the Doppler Center Frequency, a new 2 dimensional (2D) attitude steering method-New Zero Doppler Steering, is suggested through the analysis of the expression. The new method can minimize the residual Doppler Centroid to absolutely zero Hz, and if all the satellites in the formation applying this method, the beam synchronization of the system can be realized and the common Doppler spectrum of tow images is maximal. The computer simulation results prove the validity of the method and show that the accuracy of New Zero Doppler Steering method is better than the Total Zero Doppler Steering theoretically. The New Zero Doppler Steering method can be applied to the future spaceborne SAR and formation flying satellite InSAR system.