International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / Complete real time testing of a telemetry tracking system typically requires the use of a cooperative target operating under conditions specially set up to simulate actual flight scenarios. This is a very expensive, time-consuming process and does not necessarily exercise all of the functions and capabilities available in new digital antenna controllers. This paper introduces Radar Environment Simulator technology and its application to testing of telemetry tracking systems. Measured results are shown, demonstrating that operational environment simulation is a valuable approach to quickly and effectively characterize the real time operation of a telemetry tracking system.