Development and Testing of a Real-Time GPS/INS Reference System for Autonomous Automobile Navigation

M.G. Petovello, M.E. Cannon, G. Lachapelle, J. Wang, C.K.H. Wilson, O.S. Salychev and V.V. Voronov

Abstract:	Precise position and velocity information have already led to a large number of vehicle-based applications. Access to this information in real-time further opens the door to telematic applications such as en-route navigation assistance. This paper deals with the development of a real-time system to be used for the testing of proposed autonomous automobile navigation systems, whereby the driver need not actually control the vehicle. From a navigation standpoint, this requires not only very precise but also very reliable position and velocity information with high availability and low latency. These constraints are even more stringent for a reference system, whose solution is to be considered ideal, as is the case here. To this end unaided GPS is insufficient, as it does not provide the necessary availability or reliability. A loosely integrated approach using a GPS Real-Time Kinematic (RTK) and mid-level INS is therefore proposed to alleviate these problems. Given the time-critical nature of such an application, emphasis is given to the real-time aspect of the system. An implementation is presented whereby IMU data are processed as they are received and INS states are updated with inherently latent GPS data. The objective of this paper is to assess the accuracy and feasibility of such a system, which is based on the Honeywell HG-1700 IMU and the NovAtel OEM4 GPS receivers. A vehicle test was performed under varying operational conditions, including open sky, and areas where shading is encountered due to buildings, foliage and overpasses. System performance is evaluated through the accuracy of the INS only solution during periods of simulated GPS outages. Initial testing shows the system is able to bridge short GPS data gaps (1 to 5 seconds) with decimeter level accuracy under mild vehicle dynamics. Increased vehicle dynamics combined with longer GPS outages currently produce INS errors at the meter level.
Published in:	Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001) September 11 - 14, 2001 Salt Palace Convention Center Salt Lake City, UT
Pages:	2634 - 2641
Cite this article:	Petovello, M.G., Cannon, M.E., Lachapelle, G., Wang, J., Wilson, C.K.H., Salychev, O.S., Voronov, V.V., "Development and Testing of a Real-Time GPS/INS Reference System for Autonomous Automobile Navigation," Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001), Salt Lake City, UT, September 2001, pp. 2634-2641.
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