GPS Navigation: Combining Pseudorange With Continuous Carrier Phase Using a Kalman Filter

Patrick Y. C. Hwang, R. Grover Brown

Abstract: The notion of aiding GPS code-ranging information with the carrier-phase measurements has been around for quite some time, though little has been offered on it in the published literature. The integration of these two comple­mentary forms of data can provide highly precise position solutions cor­rupted by very little high-frequency error. This combination of data is particularly advantageous for high-dynamical situations. This paper presents two schemes that are based on the Kalman filter to integrate GPS code and carrier measurements efficiently. One of the schemes involves a general combination of the two types of measurements where the vehicle motion is described as a random process. In the other scheme, the continuous carrier phase measurements provide a dynamically exact reference trajectory in much the same manner as in an inertial system, and then the pseudorange data is used to update the reference trajectory via a Kalman filter. This method of integration looks especially attractive as a means of achieving good dynamical response while still retaining the bene­fits of filtering the pseudorange data. Simulated motion and real-life stationary receiver data were used to assess the characteristics of the filtering schemes under dynamical conditions. Issues involving cycle slips in the carrier phase, and their detection and correction are also discussed.
Published in: Proceedings of the 2nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1989)
September 27 - 29, 1989
The Broadmoor Hotel
Colorado Spring, CO
Pages: 185 - 190
Cite this article: Updated citation: Published in NAVIGATION, Journal of the Institute of Navigation
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