TOPSTAR 3000 – An Enhanced GPS Receiver for Space Applications

Introduction GPS receivers are now widely used for Low Earth Orbit (LEO) spacecraft applications for both scientific and commercial programmes. New applications are also under study, such as navigation in Geostationary Earth Orbit (GEO) and Geostationary Transfer Orbit (GTO), space rendezvous manoeuvres and atmospheric reentry, for which GPS receivers are promising candidates as navigation sensors. Between 1997 and 1999, under a joint ESA/CNES contract, Alcatel developed TOPSTAR 3000, a new generation of GPS receiver dedicated specifically to spacecraft applications (Fig.1). This receiver uses the L1-C/A GPS service and can serve both modular and multi-mission applications.