Miniature space GPS receivers have been developed by means of automobile-navigation technology. We expandedthe frequency sweep range in order to cover large Doppler shift on orbit. The GPS receiver was modified to outputpseudorange data with accurate time tag. We tested the performance in low earth orbits by means of a GPS simulator.The range error caused by the receiver is measured to be 0.9 meter in RMS. Receiver was on-boarded on INDEX(“REIMEI”) satellite, which was launched in 2005. Cold start positioning was confirmed repeatedly to finish within30 minutes on orbit. The orbit determination was performed to evaluate the random position error of GPS receiverby means of the residual error. The random error of GPS position is as large as 2 meter for PDDP=2.5 on orbit. TheRMS value of range error is evaluated to be 0.6m from the flight data. These results on orbit are consistent with thesimulation results in use of a GPS simulator. This miniature space GPS receiver is at present in commercial market.
展开▼
