Results of Testing on a GPS-Based Compass

Joseph Spalding and Mark Lunday

Abstract:	The use of GPS to determine vessel heading and azimuths as applied to marine navigation was investigated. By observing the GPS constellation using a multi-antenna array, the orientation of the array can be calculated relative to the GPS coordinate system. A device of this type is not subject to: variations in the earth’s magnetic field, deviations due to ship specific magnetic field effects, inertial effects caused by changes in vessel motion, inaccuracies in polar regions (above 70” latitude). A GPS based heading device also has advantages in areas of reliability (no moving parts) and the ability to get on line and settled out in minutes rather than hours. To investigate this technology and promote its development the Coast Guard R&D Center contracted through the DOT Small Business Innovative Research Program to have a device built for testing marine navigation applications. In 1994 Adroit Systems Incorporated delivered the TtiADSrM prototype attitude determination unit. Tests conducted at land based and shipboard installations demonstrated the ability of the system to reliably calculate heading. However, the short baselines in the antenna arrays exhibited unacceptable amounts of process noise for instantaneous heading solutions. Filtering of the GPS heading output was tried, but this induced unacceptable lag into the heading result. The potential for GPS devices to perform this task was clearly demonstrated. Several recommendations are given that could aid manufacturers in developing future units with acceptable performance.
Published in:	Proceedings of the 8th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1995) September 12 - 15, 1995 Palm Springs, CA
Pages:	941 - 948
Cite this article:	Spalding, Joseph, Lunday, Mark, "Results of Testing on a GPS-Based Compass," Proceedings of the 8th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1995), Palm Springs, CA, September 1995, pp. 941-948.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In