Inertially Aided Lane Recapture after GPS Carrier Lock Loss
Kinematic surveys and positioning applications based on the Global Positioning System generally require maintenance of carrier lock on four or more GPS satellites for realization of centimeter level accuracies. Frequently, short periods of carrier lock loss for one or more GPS satellites is caused by masking from trees, buildings, and bridges, and radio frequency (rf) interference. If continuous track is not maintained on at least four satellites during the outage, the lane, or integer ambiguity, must be re-established after carrier lock is regained. The use of external sensors, most notably an Inertial Navigation System (INS), can aid in recapture of the integer ambiguity after relatively short periods of loss of lock. Research by Hein et. al.  indicates these periods may be on the order of twenty to thirty seconds for high quality inertial systems. This study extends this previous work somewhat to larger lanes and lower quality inertial systems.
KeywordsSeparation Distance Inertial Navigation System Integer Ambiguity Scale Factor Error Sigma Error
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- 1.Hein, G.W., Baustert, G., Eisfeler, B., and Landau, H., “High-Precision Kinematic GPS Differential Positioning and Integration of GPS with a Ring Laser Strapdown Inertial System, Navigation, Journal of the Institute of Navigation, Vol. 36, No. 1, Spring 1989Google Scholar
- 2.Kleusberg, A., Georgiadou, Y. and Wells, D., University of New Brunswick, Fredericton, New Brunswick, Logan, K., U.S. Army Corps of Engineers, Fort Belvoir, Virginia, Geier, J. and Loomis, P., Trimble Navigation Ltd., Sunnyvale, California, “GPS Carrier Phase Ambiguity Resolution for Moving Receivers, GPSNI KIS 1990, Banff, Sep 10–13, 1990Google Scholar
- 3.Hatch, R., Magnavox Advanced Products and Systems Co., Torrance, California, “Instantaneous Ambiguity Resolution”, GPSNI KIS 1990, Banff, Sep 10–13, 1990Google Scholar
- 4.Gelb, A., Applied Optimal Estimation MIT Press, 1978.Google Scholar
- 5.Widnall, W.S., and Grundy, P.A., Inertial Navigation System Error Models, Intermetrics TR-03–73, 11 May 1973.Google Scholar
- 7.Rice, D.A., “A Geoidal Section of the United States”, XIIth General Assembly of the International Union of Geodesy and Geophysics, Helsinki, July - August 1960.Google Scholar
- 9.Precision Time and Frequency Handbook Ball Efratom Division, 1985.Google Scholar
- 10.Altshuler, Edward E., and Kalagham, Paul M., “Tropospheric Range Error Corrections for the Naystar System,” Air Force Cambridge Research Laboratories, AFCRL-TR-74–0198, April 1974.Google Scholar
- 11.Greenspan, R.L., and J.I. Donna, “Measurement Errors in GPS Observables,” Proceedings of the Forty-Second Annual Meeting of the Institute of Navigation, Seattle, Washington, June 1986.Google Scholar
- 12.Klobuchar, John A., “A First-Order, Worldwide, Ionospheric, Time-Delay Algorithm,” Air Force Cambridge Research Laboratories, AFCRL-TR-75–0502, September 1975.Google Scholar
- 13.Jorgensen, P.S., “An Assessment of Ionospheric Effects on the GPS User,” NAVIGATION, Journal of the Institute of Navition, Vol. 36, No. 2, Summer 1989.Google Scholar