Integrated Navigation System for U.S. Army Ground Vehicles

William Packard

Abstract: Current battlefield tactics and high mobility requirements demand the availability of high-accuracy aiming and position determining equipment. The Kearfott Guidance and Navigation Division of The Singer Company is currently developing such a system for application primarily to the M109 self-propelled Howitzer. This system provides added features to adapt it to a wide range of military vehicles with target location and surveillance missions. The Modular Azimuth Position System (MAPS) applies state-of-the-art strapdown sensors, Ring Laser Gyros (RLG's) and force rebalance accelerometers) to satisfy this operational requirement. The Kearfott system is designed primarily as a velocity-aided, Inertial Navigation System (INS) where the vehicle velocity data is derived from the odometer shaft-driven Vehicle Motion Sensor (VMS). The odometer data is processed by a system Kalman filter which has been specifically adapted for ground vehicle operation. Several enhancements are expected to be- introduced via Kalman filter adjustments to optimize the system performance as additional field/vehicle data are obtained. The MAPS consists of the integration of three principal subassemblies: 1) the Dynamic Reference Unit (DRU), 2} the Control Display Unit (CDU), and 3) the VMS. It is presently designed to meet a specification of 1 mil rms in grid heading, 0.5 mil rms in attitude and a position accuracy of 10 m Circular Error Probability (CEP) for distances less than 4 km and 0.25 percent of distance over 4 km. Special packaging attention has been applied to assure that the desired performance is achieved in the rigorous land battle environments which will prevail The DRU is an Inertial Navigation Unit (INU) housing the orthogonal triad of production RLG's, accelerometers, and the accelerometer electronics with support electronics (processor, memory, and RS-422 1/0 cards) and power supplies required to provide Special voltages from the vehicle de system. The CDU provides all operator interface to the system, controls all DRU system modes, inputs all data for inertial system initialization, and provides data processing for waypoint navigation. The VMS converts vehicle odometer shaft rotation into digital vehicle motion data for use by the DRU. Recent test data has been acquired in odometer-aided tests using Kearfott van and military wheeled vehicles on terrain representing battlefield conditions at Aberdeen Proving Ground. This data confirms compliance with the specified performance with significant margin. Continuing tests at Aberdeen Proving Ground are planned for 1987 to evaluate both pointing and position determination performance in several tracked vehicles (M109, M113) under various terrain and environmental conditions including multiple gun-firing exposure. This paper will provide an overview of the system architecture, its physical and functional partitioning, and results from Kearfott road testing and testing in military vehicles under rugged road conditions.
Published in: Proceedings of the 43rd Annual Meeting of The Institute of Navigation (1987)
June 23 - 25, 1987
Dayton, Ohio
Pages: 118 - 128
Cite this article: Packard, William, "Integrated Navigation System for U.S. Army Ground Vehicles," Proceedings of the 43rd Annual Meeting of The Institute of Navigation (1987), Dayton, Ohio, June 1987, pp. 118-128.
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