Attitude Estimation and Control of Spacecraft Using Global Positioning System

This paper is concerned with attitude estimation and pointing accuracy of a remote sensing satellite with off-nadir spinning scatterometer using GPS (Global Positioning System) carrier phase signals. The spinning scatterometer disturbs the three-axis desired pointing of the satellite. A three-axis controller is designed to control the earth-pointing attitude of the satellite, and its pointing accuracy is determined. The GPS satellite visibility plots identify the GPS satellites visible to the remote sensing satellite. Using single-differenced carrier phase observables of GPS an Extended Kalman Filter (EKF) is developed to estimate the attitude of the satellite over time. Simulation results are shown demonstrating the above mentioned steps.