Development of a Ground-Based Clutter Emulation Transponder to Test Airborne Space-Time Processing

A ground-based clutter emulation transponder is proposed for the cost-effective development and testing of airborne space-time adaptive processing (STAP) algorithms. The deisgn of the clutter emulator is based on uniquely modulating each output of a radar transponder having multiple transmit antennas that are spatially distributed in the cross-range dimension. During Phase I, the feasibility of using the ground-based transponder to emulate accurately the spatial and temporal characteristics of sidelobe clutter, as observed by an airborne radar, will be analyzed. The quality of the emulation will be determined by simulating the responses of selected STAP algorithms to a computer model of the transponder. The responses will be compared to the outputs that are obtained when the algorithms are exercised using existing, high-fidelity clutter simulations. For the design configurations that yield favorable comparisons, the simulation will be used to quantify the cirtical emulator parameters and thereby establish the feasibility of the concept. Both an implementation plan for the clutter emulator, and a demonstration test plan based on using the UHF RSTER system will be prepared to facilitate the transition into Phase II of the SBIR Program. Anticipated Benefits: The principal benefit of the proposed concept is the acceleration of the development of a critical enabling technology during a period of reduced defense spending. This benefit can be realized because the clutter emulator will allow existing ground-based assets, rather than costly-to-operate airborne assets, to be used during the initial stages of STAP algorithm development. The clutter transponder could be applied to the testing of systems such as air traffic control radars.