Launch vehicle tracking enhancement through Global Positioning system Metric Tracking

The USAF has embarked on an initiative known as Future Flight Safety System (FFSS) that will significantly reduce Test Range Operations and Maintenance (O&M) costs by closing facilities and decommissioning ground assets. In support of the FFSS, a GPS Metric Tracking (MT) system based on the Global Positioning System (GPS) satellite constellation has been developed that will allow Ranges to divest some of their radar assets. Successful flight testing and qualification of these systems has been conducted at Vandenberg Air Force Base (VAFB) on the Western Test Range and Cape Canaveral Air Force Station (CCAFS) on the Eastern Test Range. The GPS MT system has provided precise LV position, velocity and timing information that can replace ground radar tracking resource functionality. The GPS MT system provides an independent position/velocity S-Band telemetry downlink to support the current man-in-the-loop ground-based commanded destruct of an anomalous flight. The system utilizes a 216 channel digital receiver capable of navigating in high dynamic environments and high altitudes fed by antennas mounted diametrically opposed on the airframe skin. To enhance cost effectiveness, the GPS MT System design was implemented using existing commercial parts and common environmental and interface requirements for Launch Vehicles. The GPS MT System design is complete, successfully qualified, and has demonstrated in flight that the system performs as designed and simulated. Development of the next generation of GPS MT systems has been completed and qualification testing was successfully conducted. While the system was in production a need to improve testing was identified. Early production units were manually tested for several weeks at a time in a labor intensive manner. An automated test system concept was initiated and developed based on several concepts. The first was to reduce operator introduced errors, next was to improve repeatability of testing, and finally, automate test reports while storing data in a digital format for later in-family comparisons. This paper summarizes the current development status, system comparisons, and performance capabilities of the GPS MT system.