A GPS/inertial navigation system design evaluator

A GPS/inertial navigation system evaluator simulation tool (i.e., the ENSIM-RSIM program) is described, and results from its application to a recent GPS/inertial system concept evaluation effort are presented. The effort was directed at the development of data processing techniques for effective use of GPS measurements in the navigation system Kalman filter. The closed-loop evaluator simulation modeled the dynamic interactions of a four-channel, adaptive bandwidth GPS receiver and an inertial navigation system in a high noise environment. The study focused on the development of receiver loss-of-lock indicator algorithms which respond rapidly and accurately to changes in the status of the receiver tracking loops, and the development of effective Kalman filter designs for GPS-aided inertial navigation. The closed-loop ENSIM-RSIM evaluation of data processing options clearly demonstrated that stable accurate GPS/inertial performance is achievable.