Low Cost INS/GPS Integration: Concepts and Testing

O.S. Salychev, V.V. Voronov, M.E. Cannon, R. Nayak and G. Lachapelle

Abstract:	The high cost of inertial units is the main obstacle for their inclusion in precision navigation systems to support a variety of application areas. Standard inertial navigation systems (INS) use precise gyro and accelerometer sensors, however, newer inertial devices with compact, lower precision sensors, have become available in recent years. This group of instruments is called motion sensors. Given their weak stand-alone accuracy and poor run-to-run stability, such devices are not usable as sole navigation systems. Even the integration of a motion sensor into a navigation system as a supporting device requires the development of non-traditional approaches and algorithms. The objective of this paper is to assess the feasibility of using a motion sensor, specifically the MotionPak™,integrated with GPS and DGPS information, to provide the navigation capability to bridge GPS outages for tens of seconds. The motion sensor has three orthogonally mounted "solid-state" micromachined quartz angular rate sensors, and three high performance linear servo accelerometers mounted in a compact, rugged package. Advanced algorithms are used to integrate the GPS and motion sensor data. These include INS error damping, calculated platform corrections using GPS (or DGPS) output, velocity correction, attitude correction and error model estimation for prediction. This multi-loop algorithm structure is very robust, which guarantees a high level of software reliability. Vehicular and aircraft test trials were conducted with the system in land vehicle mode and the results are discussed. Simulated outages in GPS availability were made to assess the bridging accuracy of the system. Results show that a bridging accuracy of up to 3 m after 10 seconds in vehicular mode and a corresponding accuracy of 15 m after 60 seconds in aircraft mode can be obtained, depending on vehicle dynamics and the specific MotionPak™ unit used.
Published in:	Proceedings of the 2000 National Technical Meeting of The Institute of Navigation January 26 - 28, 2000 Pacific Hotel Disneyland Anaheim, CA
Pages:	98 - 105
Cite this article:	Salychev, O.S., Voronov, V.V., Cannon, M.E., Nayak, R., Lachapelle, G., "Low Cost INS/GPS Integration: Concepts and Testing," Proceedings of the 2000 National Technical Meeting of The Institute of Navigation, Anaheim, CA, January 2000, pp. 98-105.
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