New methods for dual constellation single receiver positioning and integrity monitoring

Abstract

Navigation system integrity monitoring is crucial for mission (e.g. safety) critical applications. Receiver autonomous integrity monitoring (RAIM) based on consistency checking of redundant measurements is widely used for many applications. However, there are many challenges to the use of RAIM associated with multiple constellations and applications with very stringent requirements. This paper discusses two positioning techniques and corresponding integrity monitoring methods. The first is the use of single frequency pseudorange-based dual constellations. It employs a new cross constellation single difference scheme to benefit from the similarities while addressing the differences between the constellations. The second technique uses dual frequency carrier phase measurements from GLONASS and the global positioning system for precise point positioning. The results show significant improvements both in positioning accuracy and integrity monitoring as a result of the use of two constellations. The dual constellation positioning and integrity monitoring algorithms have the potential to be extended to multiple constellations.

Keywords:

• receiver autonomous integrity monitoring (RAIM)
• ambiguity validation
• multiple constellations
• precise point positioning (PPP)

Acknowledgments

This research was carried out within iNsight (www.insight-gnss.org), a collaborative research project funded by the UK’s Engineering and Physical Sciences Research Council (EPSRC), to extend the applications and improve the efficiency of positioning through the exploitation of new global navigation satellite systems signals. It is being undertaken by a consortium of 12 UK university and industrial groups: Imperial College London, University College London, the University of Nottingham, the University of Westminster, the EADS Astrium, Nottingham Scientific Ltd, Leica Geosystems, the Ordnance Survey of Great Britain, QinetiQ, STMicroelectronics, Thales Research and Technology UK Limited, and the UK Civil Aviation Authority.