Highly Accurate Point Surveying and Time Transfer Using a Stand-Alone GPS Receiver

Paul W. McBurney, Janet Neumann

Abstract:	Stanford Telecom is currently producing a GPS receiver/ transmitter known as a Ground Transmitter (GT) for use in a test range environment. Prior to transmitting, the GT performs a point survey and synchronizes with GPS time. It then transmits an authentic GPS signal either continuously or in a multiplex mode during which it transmits and receives to maintain GPS time. The combination of a cesium standard and highly accurate preprocessed measurements allow the GT to achieve 3 meter positioning accuracy and 10 nanosecond timing accuracy. This paper describes the measurement preprocessing and special Kalman filter design of the two-channel receiver contained in the GT. A satellite is tracked on both 11 and 12 for five minutes during which pseudoranges are smoothed with accurate accumulated delta-range {ADR) measurements. The end result is a single pseudorange and ADR which are valid at the end of the dwell. The dominant errors which remain after smoothing are satellite ephemeris prediction errors and residual satellite clock errors. A Schmidt-Kalman filter, which includes these errors in its model, is used to keep the bandwidth of the filter wide enough to average out these errors over consecutive days. The GT can survey with less than four concurrent satellites because of the changing satellite geometry. The GT can perform its accurate survey with only two or three satellites in view, taking advantage of the changing satellite geometry over a period of time. This concept of accumulated GDOP is explained in the paper along with plots showing its benefits.
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:	483 - 492
Cite this article:	McBurney, Paul W., Neumann, Janet, "Highly Accurate Point Surveying and Time Transfer Using a Stand-Alone GPS Receiver," Proceedings of the 2nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1989), Colorado Spring, CO, September 1989, pp. 483-492.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In