DGPS Kinematic Carrier Phase Signal Simulation Analysis for Precise Velocity and Position Determination

M.E. Cannon, G. Lachapelle, M. Szarmes, J. Hebert, J. Keith, and S. Jokerst

Abstract:	The equipment, procedures and simulated aircraft trajectories used to analyze carrier phase measurements to estimate velocities and tridimensional positions using differential GPS are described. The Northern Telecom STR2760 Differential GPS Simulator System was used to generate C/A and P code and carrier phase signals from segments of the actual GPS constellation. Two pairs of dual-frequency receivers were tested, namely two Ashtech Z-12- and two NovAtel MiLLenniumTM Ll/L2 GPSCardTM units. These units have the capability of tracking the P code (Ll/L2 in the case of the Z- 12=M and L2 in the case of the MiLLenmumTM unit). An oval aircraft trajectory with accelerations up to 5 g’s was simulated and analysis is made in terms of the velocity errors and dynamics. Several methods were tested to estimate the 3-D velocities, namely carrier phase with fixed integer and real number (float) ambiguities. Both raw Doppler measurements and a number of carrier phase-derived Doppler measurements were tested. As a by-product, the 3-D positions could also be determined using various carrier phase approaches. The estimated quantities were compared to the reference quantities known a priori to determine the performance of the receivers under the various conditions simulated.
Published in:	Proceedings of the 1997 National Technical Meeting of The Institute of Navigation January 14 - 16, 1997 Loews Santa Monica Hotel Santa Monica, CA
Pages:	335 - 350
Cite this article:	Updated citation: Published in NAVIGATION: Journal of the Institute of Navigation
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