The NAVSYS GPS/Inertial Mapping (GIM) System

Josef Coetsee and Alison Brown

Abstract:	Geographic Information Systems (GIS) constitute a multi-billion dollar market for geographic data. This paper describes a low cost, miniaturized GPS/lnertial Mapping (GIMI system developed by NAVSYS to support real-time and post-test mapping applications. The NAVSYS GIM system incorporates an innovative optimal processing algorithm that enhances the performance of the inertial/GPS system, allowing a low cost inertial measurement unit (IMU) to be employed. The NAVSYS GIM system is designed to provide an accurate position and attitude reference for use in geolocation, for example in support of photogrammetry and data collection. The GIM system is ideally suited for demanding applications such as the GPSVan project at the Ohio State University Center for Mapping. The GPSVan is a vehicle designed to map highway infrastructure features at normal traffic speeds with an accuracy of l-3 meters. The van carries a Super VHS camera system which captures a photo log of the survey. By using the position and attitude data obtained from the GIM system, each video frame can be tagged and a geodetic coordinate assigned to each image. The NAVSYS GIM system determines the vehicle’s geographic position by using GPS in differential mode. To accurately generate position and attitude data even during periods of satellite shadowing due to buildings, trees, etc, the NAVSYS GIM uses an optimal estimation technique that blends data obtained from an IMU with available GPS data.
Published in:	Proceedings of the 50th Annual Meeting of The Institute of Navigation (1994) June 6 - 8, 1994 Antlers Doubletree Hotel Colorado Springs, CO
Pages:	181 - 188
Cite this article:	Coetsee, Josef, Brown, Alison, "The NAVSYS GPS/Inertial Mapping (GIM) System," Proceedings of the 50th Annual Meeting of The Institute of Navigation (1994), Colorado Springs, CO, June 1994, pp. 181-188.
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