TACTICAL GPS GUIDANCE SYSTEM.

Results are presented of a design study that defined an optimal (cost vs performance) guidance system that uses the NAVSTAR system. A description is given of the trades that led to the system configuration. A sequencing receiver (receiver that listens to one satellite at a time) was chosen. This required the navigation system to position the code and frequency of the receiver tracking loops where the receiver switches satellites. Receiver measurements are processed in a U-D formulation of a Kalman filter to update the navigation equations to perform in-flight alignment and parameter estimation of the strapdown gyro biases. Receiver and guidance system performance are presented.