Adaptive Update Strategy for GNSS/IMU Integration

M. Lu, P. Li, Z. Feng

Abstract:	In conventional GNSS/IMU integration, the updating frequency is constant, and measurements are used to execute update when they are received. As a result, the integration accuracy would be vulnerable to the degraded measurements accuracy due to GNSS signal outage or low-cost receiver. In addition, IAE is one of the proven AKF algorithms, and it has been proposed to address the issue of insufficient priori statistics by adapting system parameters. However, if the accuracy of the GNSS measurements is not guaranteed, IAE is more likely to be subjected to bias and system instability using constant updating frequency. In order to maintain the performance of integrated GNSS/IMU system with the coexistence of less accurate measurements, “adaptive update strategy” is proposed in this paper, in which not only the filter parameters are adaptive, but also the updating frequency is adaptive. According to the concept of “adaptive update strategy”, an algorithm called “measurements discarding algorithm” is proposed, it monitors the quality of the estimations and measurements in real-time, and discards the less qualified measurements. The real data test and simulation confirmed that the using of measurements discarding algorithm in EKF and IAE can improve the positioning performance of the integrated system if the measurements is degraded by additive noise. The proposed adaptive updating strategy has potential applications using less accurate GNSS measurements.
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:	750 - 758
Cite this article:	Lu, M., Li, P., Feng, Z., "Adaptive Update Strategy for GNSS/IMU Integration," Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009), Savannah, GA, September 2009, pp. 750-758.
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