Low Cost Solid State GPS/INS Package

Jose A. Rios and Elecia White

Abstract:	A low cost solid state GPS/INS navigation system has been developed that incorporates measurements from a GPS system into the DMU (Dynamic Measurement Unit) family of inertial sensor products offered by Crossbow. The DMU product alone is an accurate low-cost alternative to traditional 6-axis inertial systems and utilizes solid-state MEMS gyros and accelerometers to provide a complete determination of attitude (roll and pitch Euler angles). Firmware inside the DMU’s DSP processors provides calibrated stable angular rate measurements, calibrated stable acceleration measurements, and estimates of roll and pitch. The algorithm used to calculate attitude is an extended Kalman Filter trajectory correction approach with the accelerometers providing an attitude reference and the filter providing corrections to the attitude trajectory calculated from integration of the rate gyros. The filter also estimates gyro sensor bias errors, which allows the algorithm to perform well when the vehicle is maneuvering. Under static conditions, the attitude errors are less than 0.1 degrees. Under dynamic conditions, the performance is a function of the dynamic acceleration profile. Flight tests against a traditional high accuracy INS system demonstrate performance of +/- 2 degrees of error in low G (0.5 G) to medium G (1.5 G) maneuvering. In combining the DMU with a serial GPS, a relatively inexpensive GPS/INS integration is achieved. GPS receiver estimates of ECEF position and velocity for the vehicle are combined with DMU body frame accelerometer sensed accelerations and gyro sensed inertial angular rates at 100 Hz to provide a full navigation solution (latitude, longitude, altitude, velocity, body attitude and heading) at 100 Hz. The extended Kalman filter, augmented by the GPS estimates, provides estimates of the accelerometer bias errors and position and velocity trajectory corrections. Simulation and prototype test results show that the attitude errors while in the maneuvers described above improved to under +/- 0.5 degrees.
Published in:	Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000) September 19 - 22, 2000 Salt Palace Convention Center Salt Lake City, UT
Pages:	2593 - 2602
Cite this article:	Rios, Jose A., White, Elecia, "Low Cost Solid State GPS/INS Package," Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000), Salt Lake City, UT, September 2000, pp. 2593-2602.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In