Distributed multi-satellite measurement scheme oriented towards microsatellite formations

摘要

Existing high-precision inter-satellite radio frequency (RF) measurement systems were mostly based on two-satellite formations, and there lacks further research on measurement schemes for multi-satellite formations. The frequency division multiple access (FDMA) and the code division multiple access based schemes are widely used, but not applicable for distributed applications due to their poor scalability. The time division multiple access (TDMA) based scheme can overcome this weakness, and has been applied in the global positioning system (GPS) IIR/IIF inter-satellite link. However, the atomic clock used in GPS is not suitable for microsatellites. If a miniaturised frequency source instead of the atomic clock is utilised, the two way ranging (TWR) method adopted in this system would encounter a sharp decrease of measurement accuracy. To this end, this Letter aims to propose a novel TDMA based distributed RF measurement scheme for multi-microsatellite formations. A TDMA based distributed broadcast protocol is employed in the media access control layer, closely integrated with the asymmetric double-sided two-way ranging method adopted in the physical layer. Numerical and simulation results demonstrate the superiority of the proposed scheme over the conventional TDMA scheme. The proposed scheme can be recommended for future multi-microsatellite formation missions.