Methods for compensating inertial navigation with GPS have been described, for example, by Williamson, et. al., in “Sensor Fusion Applied to Autonomous Aerial Refueling, Journal of Guidance, Control, and Dynamics,” Vol. 32, No. 1, January-February 2009, Britting, in Inertial Navigation Systems Analysis, Wiley-Interscience, New York, 1971, and S. Hong, et. al., in Observability Analysis of GPS Aided INS, Proceedings of the 2000 Institute of Navigation, Salt Lake City, Utah, September 2000. Also, recent advances in GPS technology such as have been described by Y. E. Bar-Sever, et. al., in “Estimating horizontal gradients of tropospheric path delay with a single GPS receiver,” Journal of Geophysical Research, Vol. 103, no. B3, pages 5019-5035, Mar. 10, 1998, describe the ability to resolve integer ambiguity between a GPS receiver and the GPS satellite. The ability to resolve integer ambiguity between a GPS receiver and the GPS satellite can be used to increase position accuracy, as well as to compensate inertial drift errors by use of GPS observables.
However, most of the carrier phase observables of interest are affected by the “phase wind up effect” which has been described by Wu, et. al., in “Effects of antenna orientation on GPS carrier phase,” Manuscripta Geodetica Vol. 18, pages 91-98, 1993. The phase wind up effect causes the GPS carrier phase to advance as the GPS antenna rotates. In present day GPS compensated INS systems, there are wind up errors such as wind up errors caused by caused by the rotation of a GPS antenna.
There is a need for a system and method which can correct an inertial navigation system for inertial navigation system errors caused by carrier phase wind up.
USPTO Backgrounds
USPTO Backgrounds