USE OF THE GLOBAL POSITIONING SYSTEM FOR EVALUATING INERTIAL MEASUREMENT UNIT ERRORS

A trajectory reference system based on the Global Positioning System ( GPS) can be used instead of conventional radars during missile flight tests. The high quality of the GPS-based trajectory reference makes it useful for evaluating the performance of the missiles' inertial measu rement units. Such a system was installed and flight tested on two rec ently launched ballistic missiles. The GPS hardware configuration used on these flights is described. A Kalman filter approach is used to es timate individual inertial measurement unit errors based on the GPS ra nge and delta range data. The ability of the GPS-based system to ident ify inertial measurement unit errors is compared to that of radar; the GPS is found to provide superior estimates.