Integration of MEMS INS with GPS Carrier Phase Derived Velocity: A New Approach

Weidong Ding

Abstract:	In view of the fast development of MEMS technology, the quick reduction of MEMS sensor cost, and the continuous improvements in MEMS sensor accuracy, MEMS based INS have become an increasingly important geospatial sensor in navigation, positioning and control applications. It is believed that MEMS INS could eventually replace the conventional INS sensors in middle to lower end applications. However to fully exploit its potential, there are still many challenging issues to be solved. Compared with the tactical grade conventional strapdown INS, the performance of MEMS INS is still suffering from large errors including significant scale factor nonlinearities, misalignment, high noise, and temperature varying biases. Precisely modeling and compensating for these errors present significant challenges from several research aspects. Together with this trend, integrated geo-referencing systems for mapping applications are gradually turning from the post processing mode to the on-line processing mode. Accuracy is not the only bench mark that users are looking for, but also real-time delivery ability, for examples in UAVs and some emergency services. Also a standalone working mode is more favorable for lower end users in terms of cost reduction, and flexibility. To that end, this paper investigates an integration scenario where a standalone GPS receiver has been integrated with a MEMS INS, the Crossbow IMU400. To improve the performance, additional velocity aiding and a new integration structure have been adopted in this implementation. Processing of field test data shows that velocity determination accuracy could reach the one centimeter level when time-differenced carrier phase measurements from one single GPS receiver is processed using the proposed velocity algorithm. MEMS sensor errors have been limited to such a level that MEMS INS can be used to generate stable attitude and heading references under low dynamic conditions. These positive test results have validated the effectiveness of the proposed integration approach.
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:	2085 - 2093
Cite this article:	Ding, Weidong, "Integration of MEMS INS with GPS Carrier Phase Derived Velocity: A New Approach," 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. 2085-2093.
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