ANALYSIS OF AN INTEGRATED INERTIAL/DOPPLER-SATELLITE NAVIGATION SYSTEM: PART I. THEORY AND MATHEMATICAL MODEL.
IOWA STATE UNIV AMES ENGINEERING RESEARCH INST
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Inertial navigation systems have reached a high level of sophistication in recent years, but the effect of long-term-drift is still a problem in many applications. It has been demonstrated that position fixes obtained from the Navy Navigation Satellite System may be used to update an inertial system, but simple position updating can not correct the underlying causes of the drift nor can it correct the Schuler oscillation in the undamped case. This report describes a method of system integration whereby the Doppler data is treated directly as the observable in a Kalman-filter reset scheme. The advantage of this approach is that estimates of the inertial velocity and gyro bias errors are obtained as well as the position errors. Thus, the additional information obtained from the Kalman filter can be used to reduce the rate of error propagation in the interim between passes. Details of the Kalman filter model are presented in the report. Author
- Space Navigation and Guidance