Using an Accelerometer Configuration to Improve the Performance of a MEMS IMU: Feasibility Study with a Pedestrian Navigation Application

T. Williams, A. Pahadia, M. Petovello, G. Lachapelle

Abstract:	This paper proposes a new approach to improve the performance of a MEMS IMU namely the use of an aiding Gyroscope-Free IMU (GFIMU); a configuration of accelerometers capable of determining the motion of a rigid body. While a GFIMU is theoretically capable of replacing a traditional strapdown IMU, there are several practical issues that make the approach less that ideal. The combination of GFIMU with a gyroscope that is used in this paper is referred to as a GFIMU+. A prototype GFIMU+ was constructed by rigidly attaching five MEMS IMUS to a compact, purposedesigned plastic block. Measurements from all five triaxial accelerometers are combined with those of a single triaxial gyroscope in a novel Extended Kalman Filter (EKF). The states of the EKF comprise the angular velocity and the biases of the triaxial gyroscope and five triaxial accelerometers. The estimates from the EKF are used to form the inputs for a GPS/INS tight-integration so that the performance of the GFIMU+ and a traditional MEMS IMU can be compared at two levels; first the errors in the angular velocity and specific force estimates, and then in the position domain. Pedestrian data was collected by mounting the GFIMU+ and a tactical grade reference IMU and GPS antenna to a rigid backpack. Various routes were walked around the University of Calgary campus. It was found that in this particular application, the GFIMU+, while performing much better than the GFIMU as predicted, allowed only marginal gains over a traditional MEMS IMU using sensors of the same grade. This is likely due to the low angular dynamics in the application.
Published in:	Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009) September 22 - 25, 2009 Savannah International Convention Center Savannah, GA
Pages:	3049 - 3063
Cite this article:	Williams, T., Pahadia, A., Petovello, M., Lachapelle, G., "Using an Accelerometer Configuration to Improve the Performance of a MEMS IMU: Feasibility Study with a Pedestrian Navigation Application," Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009), Savannah, GA, September 2009, pp. 3049-3063.
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