Developmental Test and Evaluation of Helicopters Using a Precision Differential Global Positioning System

Development of new and innovative applications for high precision differential global positioning systems (DGPS) has exploded in the last two years. Real-time three-dimensional accuracy’s of under three centimeters and processed position update rates in excess of four hertz, along with position update latencies of under eighty milliseconds are now commercially available. Immediate position information of this high accuracy and rate opens up tremendous possibilities for automated machine control applications. Over the last two years, MDHS has been developing the “Portable Test Range”, a DGPS based aircraft position and velocity data archiving tool. When required, the system provides the flight crew with threedimensional guidance and power cues integrated into a simple but highly effective flight director. The Portable Test Range has been used on numerous FAA certification flight test efforts, including noise certification, heightvelocity curve development, and Category A profile development. In the Fall of 1996, the Portable Test Range was used as a flight director for a variety of complex landing approach profiles at NASA Crow’s Landing airfield. This flight test program allowed for the simultaneous acquisition of laser position data, and was an opportunity to demonstrate the system to FAA, NASA, Army, and John Volpe Department of Transportation Technical Center staff. Certification of the “Portable Test Range” for all types of fixed wing and rotary wing flight test activities is ongoing.