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A Difference Test Method for Early Detection of Slowly Growing Errors in GNSS Positioning

Published online by Cambridge University Press:  09 August 2007

Shaojun Feng  and
Washington Ochieng
Shaojun Feng
Affiliation:
(Imperial College London)
Washington Ochieng*
Affiliation:
(Imperial College London)
*
(Email: w.ochieng@imperial.ac.uk)
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Abstract

Satellite based navigation system integrity monitoring is essential both for liability and safety critical services. The threats to system integrity are the potential failure modes that could occur at system, operational and user sensor levels. Research on identification, characterisation and modelling of such failure modes, suggests that failures that grow slowly over time (e.g. ramp error less than 2 m/s), also referred to as slowly growing errors (SGE) are the most difficult to detect early. Conventional snapshot algorithms detect SGEs when the test statistic crosses the threshold usually after relatively long periods of time. A recent concept based on the average of residuals over time has been found to have a significant weakness. This paper proposes a “difference test” algorithm capable of detecting SGEs early. In this method, the test statistic is the difference between the norm of current residuals and the norm of the residuals at a previous epoch. The distribution of the test statistic is over-bounded by a normal distribution whose parameters are derived from two Chi-distributions. Results show that the new algorithm results in a significant reduction in detection time compared to conventional methods.

Keywords

GNSSSystem IntegritySlowly growing errors
Type
Research Article
Information
The Journal of Navigation , Volume 60 , Issue 3 , September 2007 , pp. 427 - 442
Copyright
Copyright © The Royal Institute of Navigation 2007

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References

REFERENCES

Abramowita, M., Stegun, I. A. (1970). Handbook of mathematical functions with formulas, graphs and mathematical tables. Dover Publications, Inc., New York.Google Scholar
DeCleene, B. (2000), Defining Pseudorange Integrity-Overbounding, Proceedings of ION GPS 2000, Salt Lake City, UT, 19–22, September, 1916–1924Google Scholar
Diesel, J., and Luu, S., (1995) GPS/IRS AIME: Calculation of thresholds and protection radius using Chi-square methods, Proceedings of ION GPS 1995, Palm Springs, CA, 12–15, September, 1959–1964Google Scholar
Feng, S., and Ochieng, W. Y., (2006a), User Level Autonomous Integrity Monitoring for Seamless Positioning in All Conditions and Environments, Proceedings of the European Navigation Conference, Manchester, 7–10, May, 2006Google Scholar
Feng, S., Ochieng, W. Y., Walsh, D. and Ioannides, R., (2006b), A measurement domain receiver autonomous integrity monitoring algorithm, GPS Solutions Journal, 10 (2), 85–96CrossRefGoogle Scholar
ICAO (2006), Annex 10 Aeronautical Telecommunications, Volume I Radio Navigation Aids (Sixth Edition), 23/11/2006, 3–70.Google Scholar
Lee, Y. C., O'Laughlin, D. G., (1999). Performance analysis of a tightly coupled GPS/inertial system for two integrity monitoring methods, Proceedings of ION GPS 1999, Nashville, Tennessee, 14–17, September, 1187–1197Google Scholar
Ober, P. B., Farnworth, R., Breeuwer, , et al. , (2001), SBAS Integrity Verification, Proceedings of ION GPS 2001, Salt Lake City, UT, 11–14Google Scholar
Ochieng, W. Y. et al. . (2003). GPS integrity and potential impact on aviation safety. The Journal of Navigation, 56, 51–65CrossRefGoogle Scholar
Parkinson, B. W., and Axelrad, P., (1988), Autonomous GPS Integrity Monitoring Using the Pseudorange Residual, NAVIGATION: Journal of the Institute of Navigation, 35(2), pp255–274Google Scholar
Rife, J., Walter, T., Blanch, J., (2004), Overbounding SBAS and GBAS Error Distributions with Excess-Mass functions, Proceedings of the 2004 International Symposium on GNSS/GPS, Sydney, AustraliaGoogle Scholar
Tiemeyer, B. (2002). Performance evaluation of satellite navigation and safety case development. http://137.193.200.177/ediss/tiemeyer-bernd/inhalt.pdfGoogle Scholar