Use of global positioning system for gravity probe B relativity experiment and co-experiments

The primary objective of the Gravity Probe B (GP-B) Relativity Mission is to measure the relativistic drift of an Earth-orbiting gyroscope as predicted by the General Theory of Relativity. The Global Positioning System (GPS) will play one of the key roles providing time tags for the measurements and the velocity information to calibrate the cryogenic sensors. A spaceborne GPS receiver, implemented on the GP-B spacecraft, will provide real-time position, velocity, attitude solutions, timing pulses and raw measurements for post-processing that are necessary for the relativity experiment. In addition, it will be one of the primary navigation sensors for the clock, geodesy and (C) 2000 COSPAR. Published by Elsevier Science Ltd.