Contribution to Spacecraft Navigation and Timing with GPS and GALILEO

Paper number

IAC-07-B2.3.06

Author

Mr. Daniel Dassaud, Centre National d'Etudes Spatiales (CNES), France

Coauthor

Mr. Jean Luc Issler, Centre National d'Etudes Spatiales (CNES), France

Coauthor

Mr. Lionel Ries, Centre National d'Etudes Spatiales (CNES), France

Coauthor

Mr. Antoine Richard De Latour, Centre National d'Etudes Spatiales (CNES), France

Coauthor

Mr. Michel Grondin, Centre National d'Etudes Spatiales (CNES), France

Year

2007

Abstract

Most space applications need to have a real time on-board positioning and timing information. This paper presents the positioning and timing accuracy that we can get using GPS and Galileo radio navigation signals on-board space vehicle in Low Earth Orbit (LEO), High Elliptical Earth orbit (HEO) or Geostationary Earth Orbit (GEO).

First of all, the paper presents our contribution to positioning and timing of spacecrafts thanks to GPS, using the TOPSTAR 3000 family of spaceborne GNSS receivers specified by CNES and ESA. A dozen of these equipments already flew in orbit or even on board the Atmospheric Re-entry Demonstrating capsule (ARD) launched by ARIANE 503 in 1998. Moreover, about one hundred more equipments have been ordered.
Flight results will be provided, including the performances of the CNES-made “DIOGENE” on board Kalman filter, with single frequency or dual frequency GPS measurements. The positioning accuracy is 30 cm in radial if broadcasted GPS ephemeris are used. These DIOGENE accuracy results have been obtained using the TOPEX-POSEIDON downloaded dual frequency raw measurements. DIOGENE flight results will be also provided, as observed on board the HETE2 ( NASA and MIT ) and DEMETER ( CNES ) missions. These missions use single frequency TOPSTAR receivers, and robust navigations with a radial accuracy of 3 meters. Moreover, DEMETER used successfully Autonomous Orbit Control (AOC) thanks to GPS, and the main AOC results will be also presented. 

All this experiences allows to better predict future space navigation system accuracies using GALILEO, in LEO, HEO and GEO orbits.. The positioning and timing solutions have been estimated with two types of navigation algorithms which deliver the well-known single-point solution and the Kalman filtered solution. The analysis shows that Galileo signals enables very good positioning and timing accuracy for LEO and that tracking Galileo signals in HEO and GEO can be achieved with optimized signal processing techniques. Moreover, since GPS and GALILEO has two common frequencies and signals, this allows to increase the accuracy and the robustness of GNSS navigation thanks to a simple equipment.

Abstract document

IAC-07-B2.3.06.pdf

Manuscript document

IAC-07-B2.3.06.pdf (🔒 authorized access only).

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