The North Finding Module

L. W. Stimac, John R. Washburn, Greg Routson

Abstract:	This paper presents a system description, design details and iperformance data for the Smiths Indus- tries low cost North Finding Module (NFM) as de- veloped for the U.S. Army Research Lab (ARL) and the U.S. Army Missile Command (MICOM). The system contains inertial instruments (gyroscopes and accelerometers) and is integrated with a Preci- sion Low Cost GPS Receiver (PLGR). The low cost Collins receiver was integrated with the NFM using a fifteen state Kalman filter utilizing GPS position and velocity as measurements. The major require- ment of the NFM is to find north in three minutes in gyrocompass mode and within one minute in a dy- namic environment, from an initial heading uncer- tainty of 180 degrees. An extensive system execu- tive adapts the Kalman filter measurements and processes to the current environment, i.e. all avail- able measurements are optimally utilized in the presence of physical motion, the state of the GPS receiver, heading uncertainty, etc. The hardware design uses low cost Smiths Industries Dynamically Tuned Gyroscopes and Sundstrand RBA-500 accel- erometers. Field test data is presented to show compliance with the specification.
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:	979 - 988
Cite this article:	Updated citation: Published in NAVIGATION: Journal of the Institute of Navigation
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