Single-antenna attitude determination for Fedsat with improved antenna gain patterns

摘要

The GPS receiver on FedSat is a single antenna unit which supplied by NASA Jet Propulsion Laboratory (JPL) and integrated on the satellite by the Queensland University of Technology (QUT) and other participants in the Cooperative Research Centre for Satellite System. The high-level objectives, for the GPS receiver on the FedSat mission, are to provide an orbit determination capability and an attitude determination capability, whilst operating within strict power budget requirements. The current baseline is a total of 30 minutes of operation per 100-minute orbit. ududThis paper presents the history of the attitude determination capability for FedSat and an outline of the antenna gain pattern tests performed for FedSat. These tests show the great impact that the spacecraft has on the measured antenna gain pattern. Extensive data collection and simulation of different antenna gain patterns was made using a GPS constellation simulator. The accuracy of the attitude determination problem results, are shown to be within 30 degrees for the signal to noise ratio (SNR) weighted approach and were improved to within 5 degrees when mapping of the SNR to elevation angle approach is taken. Recommendations for new improved approaches, in both the methodology and in the choice of antenna gain pattern are made.