To simultaneously solve the problems of the robustness,decoupling control and high accuracy tracking control at the high tracking rate in antenna control system,a new nonlinear antenna tracking-pointing control system for user-satellite was proposed based on a unique nonlinear active disturbance rejection control method.

According to the characteristics of distributed satellites INSAR system, this paper derives the relation between the antenna pointing error and the antenna beam misalignment, analyses the influences induced by azimuth beam misalignment on receiving signal-to-noise ratio, Doppler centroid and azimuth ambiguity-to-signal ratio and the resulting height error.

This paper introduces the principle of spotlight SAR, derives the simplified formulas for calculating the antenna direction of the stabilized platform, and presents the software block diagram of a single chip computer assembler language.