OPTIMAL FILTERING OF PSEUDORANGES AND PHASES FROM SINGLE-FREQUENCY GPS RECEIVERS

Clyde C. Goad

Peer Reviewed

Abstract:	An algorithm for processing strapdown inertial data in an earth-&d Cartesian frame is developed in this paper. It is compared with the standard algorithm that uses the local-level frame and the geographic coordinate system for the model formulation. A general formulation of the modeling equations for the two approaches is given, and the linearization of the equations and the formulation of the appropriate Kalman filter are outlined. The derivation of the reference gravity model for both frames is briefly discussed, and numerically efficient formulas for the model’s computation are given. In the case of the Cartesian algorithm, this leads to new formulas for all three components of the gravity vector. Real data are used to compare the two algorithms and to show that the accuracy is the same in both cases, but that the Cartesian formulation is about 30 percent more efficient.
Published in:	NAVIGATION: Journal of the Institute of Navigation, Volume 37, Number 3
Pages:	249 - 262
Cite this article:	Goad, Clyde C., "OPTIMAL FILTERING OF PSEUDORANGES AND PHASES FROM SINGLE-FREQUENCY GPS RECEIVERS", NAVIGATION: Journal of The Institute of Navigation, Vol. 37, No. 3, Fall 1990, pp. 249-262.
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