Attitude determination techniques for Nimbus 6 and Nimbus G

Abstract

Techniques for measuring attitude deviations in the Nimbus 6 and Nimbus G 3-axis stabilized, zero-momentum, earth observation satellites are presented. The on-orbit telemetered data include scanner roll and pitch error signals, an illuminated DSAS which can read the azimuth and elevation of the sunline when the spacecraft is not in the umbra, the signal from the single gyro in the RMP, and the momenta of the reaction wheels. Mathematical methods for interpreting the measured data are described with attention to filter equations, especially the Kalman filter because of its ability to eliminate high frequency noise.