Johns Hopkins University, Applied Physics Laboratory
Development of a GPS based Tracking System for Missile Test & Evaluation
Test and evaluation is necessary to determine the effectiveness model of the missile system for high confidence performance prediction, enabling optimal utilization of system assets. A missile tracking system, using Global Positioning System(GPS) satellites, was developed to provide precision trajectory measurements over most of the missile test flight to extract the maximum performance information from each test. The tracking system consisted of a translator in the missile relaying GPS wide band signals to surface receiving stations for digital recording. The recordings were later processed to extract precision range and Doppler, correct for known errors, and combined with missile guidance telemetry in a large (up to 450 states) Kalman filter to estimate the trajectory and the many underlying error sources (up to 100). This yielded a detailed evaluation of all the performance contributors for that test. These estimates were periodically combined with other test flights in a system identification algorithm to determine the statistical performance model of the missile system. The presentation will summarize the development of the tracking and evaluation system, emphasizing the practical problems and design issues encountered.