A NAVIGATION SYSTEM UTILIZING YAW RATE CONSTRAINT DURING INERTIAL DEAD RECKONING

摘要

A system operating in a dead reckoning mode accumulates relative yawmeasurements, i.e., measurements of rotation about a z-axis, made by one ormore overmechanization update intervals and produces dead reckoning mechanizationupdate values.The system accumulates the values over a turn rate accumulation period,calculates a yaw rateand determines if the yaw rate exceeds a turn rate threshold. If so, thesystem directs an INSfilter to perform a zero yaw rate update at the start of a next mechanizationupdate interval, tocorrect for the z-axis drift errors of the gyroscopes based on the sensedrotation in the relativeyaw measurements over the previous mechanization update interval. The systemthen sets thez-axis drift errors to zero. If the system determines that the yaw rateexceeds the turn ratethreshold, the zero yaw rate update is not performed at the start of the nextmechanizationupdate interval.