Reliability of Ambiguity Resolution Using GPS and GLONASS

Richard B. Ong, Mark G. Petovello and Gerard Lachapelle

Abstract:	Differential carrier phase ambiguity resolution is often used to achieve sub-decimetre positioning accuracy for numerous applications. The reliability of the fixed-integer ambiguities is a major concern, as any error introduces position biases. GPS measurements alone may not provide the necessary observability on the ambiguities to fix them correctly or to detect when they are incorrectly fixed. GLONASS, which is nearly fully operational, can provide additional measurements to improve the observability. With a full constellation expected in early 2010, GLONASS is becoming an attractive option for augmenting GPS. This paper investigates the reliability of ambiguity resolution for relative vehicle navigation over short intervehicle distances. Tests were conducted in a residential area with two types of sky coverage: open sky and overhead foliage. The impact of GLONASS was evaluated through the performance of two reliability metrics: the predicted success rate and the F-test. In all of the visibility conditions that were tested, using GLONASS measurements and fixing the GLONASS ambiguities improved both the overall rate of correct fix and the rate of detection for incorrect fix. Surprisingly, it was found that single-frequency phase data minimizes the rate of incorrect fixes that go undetected; however this was balanced by the fact that dual-frequency phase data maximizes the rate of correct fix.
Published in:	Proceedings of the 2010 International Technical Meeting of The Institute of Navigation January 25 - 27, 2010 Catamaran Resort Hotel San Diego, CA
Pages:	591 - 606
Cite this article:	Ong, Richard B., Petovello, Mark G., Lachapelle, Gerard, "Reliability of Ambiguity Resolution Using GPS and GLONASS," Proceedings of the 2010 International Technical Meeting of The Institute of Navigation, San Diego, CA, January 2010, pp. 591-606.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In