An Incremental Velocity Measurement Algorithm for Use in Inertial Navigation Alignment
IOWA STATE UNIV AMES ENGINEERING RESEARCH INST
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In any inertial navigation system the platform must be initially aligned in some known frame of reference prior to operation in the navigation mode. Self-alignment methods are preferred in most applications, and the usual procedure is to align the platform locally level with one accelerometer axis pointing north. In the current generation of aircraft inertial systems the sensed acceleration is in the form of incremental velocity pulses. A new approach to the alignment problem is considered in this report whereby the incremental velocity pulses are modeled directly as the measurement sequence. This leads to three important changes in the filter model Aperiodic sampling is obtained Measurement noise due to granlarity is eliminated and A delayed state appears in the measurement equation. This latter condition forces the use of a modified form of the Kalman recursive equations. Results of Monte Carlo simulations for one set of noise parameters are given.
- Navigation and Guidance