Visibility Analysis of the GPS Space Segment for the BIRD Satellite Mission

Abstract

To assure that the BIRD GEM-S receiver can track a sufficient number of GPS satellites throughout its operations, the visibility conditions have been analyzed for various antenna configurations and spacecraft orientations. As a result, GPS operations will primarily be conducted in the Sun Pointing mode. Considering the requirements, that more than 4 satellites shall be visible durch 85 % of the receiver operations time and that the GDOP (geometric dilution of precision) shall be less than 5 (50 th percentile) we conclude, that a rotation of the spacecraft about its zaxis with a period of one orbital revolution is mandatory. Potential conflicts with the radiator operations have to be resolved.