Differential GPS-Based Ultra-High Accuracy Real Time Attitude Determination

Benjamin H. Wu, Stephen R. Peck, Shuwu Wu

Abstract:	Real time determination of rotational motion relies on GPS and inertial measurements. The three rotational angles, roll, pitch and yaw (or heading), can be determined by employing a Kalman filter that blends GPS measurements with gyroscope and accelerometer measurements. Due to presence of earth gravity, roll and pitch can be determined to an accuracy of about 0.025 milliradians in a high quality inertial navigation system. However, heading accuracy is typically around 1 to 2 milliradians for a navigation system that experiences low dynamics. In this paper, we propose a novel differential GPS-based technique that relies on high integrity carrier phase integer ambiguity resolution to achieve heading accuracy on the order of 0.05 milliradians, which is more than 20 times better than that of conventional technology. The new approach not only can achieve ultra-high accuracy in heading, but also provides high integrity assurance suitable for safety-of-life applications. In this paper, relevant differential GPS and inertial navigation technology is briefly reviewed. A complete high data rate real time attitude determination system is proposed. A system performance simulation tool was developed in Matlab/SimulinkTM to model ship motion under various sea states, realistic GPS and navigation-grade inertial sensor performance, conventional GPS/inertial navigation processing, attitude determination via differential GPS processing, and final heading updates that achieves ultra-high accuracy. We have conducted system performance studies, and the results have demonstrated that our proposed system achieves ultra-high heading accuracy with high integrity. Furthermore, the proposed system can be readily built by using existing GPS and inertial sensor technologies.
Published in:	Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011) September 20 - 23, 2011 Oregon Convention Center, Portland, Oregon Portland, OR
Pages:	1877 - 1887
Cite this article:	Wu, Benjamin H., Peck, Stephen R., Wu, Shuwu, "Differential GPS-Based Ultra-High Accuracy Real Time Attitude Determination," Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011), Portland, OR, September 2011, pp. 1877-1887.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In