A Novel Server Based Positioning Algorithm with Reduced Over the Air Messaging Traffic

Mangesh Chansarkar, Gengsheng Zhang, Marlene Wan and Makarand Phatak

Abstract:	Typical server based positioning algorithms require sending several pieces of information over the air between server and clients. A typical exchange of information involves aiding information like Time, GPS SV code phase and Doppler from server to client, and GPS code phase and Doppler measurements from client to server. The server would then compute a Position using usual Positioning algorithms (for example: a Weighted Least Squares Positioning Algorithm). A novel way to reduce messaging traffic without impacting the overall accuracy of the positioning has been developed and implemented in SiRF Technology, Inc., which involves: not sending the SV code phase and Doppler aid from server to the client, and compute position in the client using available almanac in the client. This computed position is then sent back to the server with associated information defining the almanac which is used for the position computation. The server Positioning system then corrects the Almanac based client position using the ephemeris information in the server for the SV measurements that have been used in the position computation in the client. The server is required to keep a small database of Almanacs which might be used by various clients that would talk to the server for the position computation purpose. Simulation results are presented to validate the position accuracy of the proposed algorithm under various signal level conditions showing that the position accuracy is comparable to the usual positioning algorithms in the server. Real test data collected using the SiRF server – client system is also presented to validate the overall operation of the proposed algorithm.
Published in:	Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005) September 13 - 16, 2005 Long Beach Convention Center Long Beach, CA
Pages:	104 - 112
Cite this article:	Chansarkar, Mangesh, Zhang, Gengsheng, Wan, Marlene, Phatak, Makarand, "A Novel Server Based Positioning Algorithm with Reduced Over the Air Messaging Traffic," Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005), Long Beach, CA, September 2005, pp. 104-112.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In