A Proposal For A Dynamic Test Platform For Inertial Units And/Or GPS

Bal N. Agamuta, Diniar M. Shroff, Stan C. Maki

Abstract:	The test platform, an equivalent 4-axis gimbal system,is on a 2-axis rotary mount attached to a tip of boom, driven by an elevation-over-azimuth drive system. The dynamic platform derives or emulates attitude, position and velocity data. The primary objective is to provide a "gross check" of precision navigation and attitude measurement systems, typically strapdown or gimballed inertial measurement units (IMU), differential GPS (DGPS) , attitude determining GPS, and tightly or loosely’ coupled IMU-GPS. As proposed, it would extend the payload and test capabilities of the Navy’s version of a movable antenna platform (MAP) GPS dynamic tester, currently under test and evaluation at Imperial Beach, CA. The crucial task is to optimally derive the truth data with which to verify the output of the unit under test (UUT). It is found that the unfiltered truth data, defined here as the measurement data or vector, is contaminated by nonstationary and correlated noise, requiring a filter with excellent smoothing and noise rejection properties. An adaptive recursive filter is applied for that purpose. The adaptive coefficients are functions of platform and model dynamics and input noise or error variance estimates. The truth data, although not of high grade inertial and precision DGPS quality, prescribes the thresholds or limits of performance and accuracy. Alternately, a proven preoision unit may be mounted on the platform to provide a redundant truth data. Analysis and simulation results are presented. The platform design, interface, tart, performance and accuracy requirements are also specified.
Published in:	Proceedings of the 1991 National Technical Meeting of The Institute of Navigation January 22 - 24, 1991 Sheraton San Marcos Hotel Phoenix, AZ
Pages:	371 - 381
Cite this article:	Agamuta, Bal N., Shroff, Diniar M., Maki, Stan C., "A Proposal For A Dynamic Test Platform For Inertial Units And/Or GPS," Proceedings of the 1991 National Technical Meeting of The Institute of Navigation, Phoenix, AZ, January 1991, pp. 371-381.
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