In Flight Estimation of Gyro and Accelerometer Scale Factors for Tactical and MEMS IMUs

Martin Becker, Ulf Bestmann, Andreas Sasse, Meiko Steen, and Peter Hecker

Abstract:	This paper deals with the estimation of scale factor errors of gyros and accelerometers of strapdown inertial measurement units (IMUs) within integrated INS/GNSS navigation systems. Therefore, a state of the art error state model, considering 15-error states, has been extended to a 21-error state model. It additionally includes the linear scale factor errors of the six inertial sensors. These models have been implemented in the coupling filter, realized as a Kalman filter, of the closed-loop integrated navigation system of the Institute of Flight Guidance (IFF) at the TU Braunschweig. For the derivation of the models the perturbation method has been used. The performance of the extended model, presented in this paper was analyzed and compared with the existing 15- error state model, which has been used by default for data processing at the IFF. Two different grades of IMUs have been taken into account. These are a mid cost IMU including MEMS accelerometers and tactical grade IMUs serving as reference system. It is shown that the navigation performance can be significantly improved by considering the scale factor errors in the strapdown navigation calculation. For assessing the improvements several aspects were taken into account. For example, the capability of the coupling filter to identify artificial applied sensor errors, the estimation of the errors themselves and finally the position error development during a GNSS outage.
Published in:	Proceedings of the 20th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2007) September 25 - 28, 2007 Fort Worth Convention Center Fort Worth, TX
Pages:	2056 - 2065
Cite this article:	Becker, Martin, Bestmann, Ulf, Sasse, Andreas, Steen, Meiko, Hecker, Peter, "In Flight Estimation of Gyro and Accelerometer Scale Factors for Tactical and MEMS IMUs," Proceedings of the 20th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2007), Fort Worth, TX, September 2007, pp. 2056-2065.
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