Abstract:

The attitude maneuver parameter is derived from six elements of satellite orbit in ECI for traditional yaw-steering method. Only the Doppler centroid frequency of satellite main axis is compensated to zero．The error slant range and Doppler centroid frequency drift arose by the installation error between antenna and satellite and the beam angle departing from coordinate axis in elevation and azimuth direction are not removed．The requirements of SAR system time order and on-board real-time processor of response SAR satellite isn′t satisfied. A new strategy of SAR antenna beam to target in zeros-Doppler plane of ECF was proposed so that Doppler frequency of beam center for fast response SAR satellite would be zero. Firstly, the accurate time order and look parameter was computed. Secondly, satellite’s three axes direction was derived from SAR beam’s three axes direction in ECF. Finally, the attitude maneuver parameters were obtained. The simulation results by Matlab show that applying the strategy to the fast response SAR satellite, the Doppler frequency 29 kHz of earth rotation, 360 Hz of installation error and 3950 Hz of the beam departing angle are compensated to 0 Hz．Simultaneously the slant error 6.28 km is compensated to meter level.

Key words: fast response SAR satellite, zero Doppler beam center, slantrange, design of time order, attitude maneuver