Spacecraft attitude estimation using the Global Positioning System - Methodology and results for RADCAL

Methodology and results for the Global Positioning System based attitude determination of a gravity gradient stabilized satellite are presented. Algorithms for on-orbit antenna baseline estimation, attitude initialization, point solution, and Kalman filtering are described. These algorithms are demonstrated using flight data collected on board the U.S. Air Force RADCAL Satellite. The precision of the final attitude estimates is assessed to be at the level of 0.4 deg for pitch and roll and 0.7 deg for yaw.