Impact of Rapid Temperature Change on Firefighter Tracking in GPS-denied Environments Using Inexpensive MEMS IMUs

Todd Faulkner and Stephen Chestnut

Abstract:	This paper investigates the impact of rapid temperature change on position errors when using a low cost MEMS IMU (Memsense nIMU) integrated with a compass for foot-based pedestrian navigation in a GPS-denied environment. A conventional six degree-of-freedom navigation solution is computed by integration of the inertial navigation equations. Position errors are effectively minimized by the use of zero-velocity updates (ZUPT) and heading updates in an extended Kalman filter. Compensating for changes in temperature presents a challenge for IMUbased firefighter tracking. Rapid temperature changes alter correlated gyro errors, increasing heading and position errors. A simulation and two 15 minute data collections are shown for comparison. Position errors for a simulated 15 minute walk based on a simplified IMU error model and a white Gaussian noise compass error model are shown as a best case comparison. Position errors are also presented for a data collection after allowing the IMU temperature to stabilize and for data acquired where the IMU underwent rapid temperature change. Results show the impact of temperature gradients on position errors during a 15 minute walk using manufacturer delivered gyro compensation values. Custom calibration procedures may improve performance by compensating for the correlated gyro errors that occur for a range of temperature gradients to mitigate position errors.
Published in:	Proceedings of the 2008 National Technical Meeting of The Institute of Navigation January 28 - 30, 2008 The Catamaran Resort Hotel San Diego, CA
Pages:	828 - 834
Cite this article:	Faulkner, Todd, Chestnut, Stephen, "Impact of Rapid Temperature Change on Firefighter Tracking in GPS-denied Environments Using Inexpensive MEMS IMUs," Proceedings of the 2008 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 2008, pp. 828-834.
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