ELECTROSTATIC ACCELEROMETER AS AN ADVANTAGEOUS COMPONENT OF PRECISE ATTITUDE AND ORBIT CONTROL SYSTEM

Satellite attitude control systems most often use star sensors to measure the satellite attitude. This well known method presents a good resolution for low frequencies; however in some cases it is interesting to have a more precise attitude control by increasing the functioning bandwidth. Angular accelerations delivered by electrostatic accelerometer such as those developed by ONERA may notably complement star sensor measurements. This instrument presents a very good resolution at higher frequencies (typically in the bandwidth 10-4 – 10-1 Hz). However, the accelerometer introduces a bias and a scale factor whose limited knowledge affects the accuracy of the measurement. An original method to estimate these parameters, by means of a least square fit to the star sensor measurements is described in this paper.The combination of the star sensor and adjusted accelerometer measurement, with fine actuators, will improve the accuracy of the attitude control.