Abstract: Techniques for monitoring and controlling yawing of a GPS satellite in an orbit that has an eclipsing portion out of the sunlight based on the orbital conditions of the GPS satellite. In one embodiment, a constant yaw bias is generated in the attitude control system of the GPS satellite to control the yawing of the GPS satellite when it is in the shadow of the earth.

Abstract: An improved analyzing system based on GIPSY-OASIS II software package developed at the Jet Propulsion Laboratory for Global Positioning System, general satellite tracking, orbit determination and trajectory studies. New features and functions include yaw compensation, precise satellite positioning by high-rate GPS clocks, enhanced data filtering and smoothing, a new user interface for controlling orientation of a satellite and its components, and no-fiducial approach to global geodesy. The present invention allows a fully automatic operation and delivery of validated daily solutions for orbits, clocks, station locations and others with no human intervention. A 3D GPS orbit accuracy of 15 cm and the daily repeatability of the 3D global geocentric station location in better than 1 cm have been achieved.