Clock Coasting Using Carrier Phase Measurements

Paul Kline

Abstract:	The purpose of this research was to evaluate the accuracy of clock aided position solutions relative to other DGPS solutions, particularly in the vertical direction. A flight test was conducted at the FAA Technical Center in Atlantic City using the Ohio University Flight Reference/Autoland System. Two Ashtech Z-12 receivers were augmented by external rubidium oscillators for the flight. It is shown that if four or more satellites are available for at least two minutes, an accurate clock estimate can be formed which improves vertical accuracy by reducing the vertical dilution of precision (VDOP). Navigation with three satellites is also illustrated. A standard clock model based on code phase measurements is presented. A new method of clock modeling that incorporates carrier phase measurements is then introduced. This has three operational benefits: I) the model provides better clock etimates than a model based solely on code phase measurements, 2) the model requires less prior data to form an accurate clock estimate, and 3) the model is able to follow rapid changes in the clock state without filtering delays.
Published in:	Proceedings of the 1998 National Technical Meeting of The Institute of Navigation January 21 - 23, 1998 Westin Long Beach Hotel Long Beach, CA
Pages:	611 - 623
Cite this article:	Kline, Paul, "Clock Coasting Using Carrier Phase Measurements," Proceedings of the 1998 National Technical Meeting of The Institute of Navigation, Long Beach, CA, January 1998, pp. 611-623.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In