Using the GPS to Improve Trajectory Position and Velocity Determination during Real-Time Ejection Seat Test and Evaluation

Test and evaluation of the United States Air Force's latest aircraft escape system technology requires accurate position and velocity profiles during each test to determine the relative positions between the aircraft, ejection seat, manikin and the ground. Current rocket sled testing relies on expensive ground based multiple camera systems to determine the position and velocity profiles. While these systems are satisfactory at determining seat and manikin trajectories for sled testing, their accuracy decreases when they are used for in-flight testing, especially at high altitudes. This research presents the design and test results from a new GPS-based system capable of monitoring all major ejection test components (including multiple ejection seat systems) during an entire escape system test run. This portable system can easily be integrated into the test manikin, within the flight equipment, or in the ejection seat. Small, low-power, lightweight Global Positioning System (GPS) GPS receivers, capable of handling high-accelerations, are mounted on the desired escape system component to maintain track during the escape system test sequence from initiation until the final landing. The GPS-based system will be used to augment the telemetry and photography systems currently being used at the Air Force (AF) and other Department of Defense's (DoD) sled track test facilities to improve tracking accuracy and reduce testing costs.