Sensing Technologies for Formation Flying Spacecraft in LEO using CDGPS and an Inter-Spacecraft Communications System

Chan-Woo Park, Jonathan P. How and Larry Capots

Abstract:	This paper describes research on sensing technologies that could be used for formation flying spacecraft in low earth orbit (LEO). The approach is based on a combination of carrier-phase differential GPS (CDGPS) sensors and GPS-like transceivers. Note that formation flying also requires a sophisticated inter-spacecraft communications system. There are several RF-based communication devices that are currently being developed for the formation flying application, and these could also be used as local (onboard) ranging systems. By providing additional inter-spacecraft range and Doppler measurements to the navigation solution, these onboard transmitters could facilitate the use of CDGPS for orbits in which adequate visibility/geometry to the NAVSTAR constellation is not available. In addition, carrier phase cycle ambiguity can be rapidly initialized using relative vehicle motions. This paper discusses this augmentation concept in detail and presents an extension of previous results [17] that significantly improves the bias initialization process. This paper also addresses some key measurement errors associated with formation flying spacecraft that are separated by long baselines (10–100km). Finally, we present experimental data on a new terrestrial testbed that has been developed to investigate relative navigation and formation flying with combined NAVSTAR and onboard (GPS) transmitters. Results are presented to show the vehicle formation undergoing initialization (short) and formation maneuvers.
Published in:	Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000) September 19 - 22, 2000 Salt Palace Convention Center Salt Lake City, UT
Pages:	1595 - 1607
Cite this article:	Park, Chan-Woo, How, Jonathan P., Capots, Larry, "Sensing Technologies for Formation Flying Spacecraft in LEO using CDGPS and an Inter-Spacecraft Communications System," Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000), Salt Lake City, UT, September 2000, pp. 1595-1607.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In