An ameliorative method of Zero Doppler Steering

As we know that 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 attitude steering method - New Zero Doppler Steering (NZDS), is suggested through the analysis of the expression. The new method can minimize the residual Doppler Centroid to absolutely zero Hz. The computer simulation results prove the validity of the method and show that the accuracy of NZDS method is better than the Total Zero Doppler Steering (TZDS) theoretically. The NZDS method can be applied to the future spaceborne SAR and formation flying satellite InSAR system.