The Army needs small acoustic sensors that can provide good angle estimation at low frequencies. The TecFocus/CornerTurn team proposes to show the feasibility of a small baseline acoustic sensor for in-air use based upon pressure gradient microphone concepts proven in Navy sonars. To assure an adequate demonstration of feasibility a limited field demonstration of a sensor unit using either recorded or simulated vehicle radiated noise will be performed. This demonstration will utilize a prototype sensor unit and PC-based (non-real time) processing to estimate the bearing of in-air signals, providing a measurement of bearing accuracy under realistic conditions. This will be supplemented by an analysis of bearing estimation performance under more general conditions, as well as the sensitivity of bearing accuracy to practical limitations such as fidelity of microphone directional response and the amplitude/phase errors of the microphone channels. Bearing accuracy will be extrapolated to Army signals and scenarios to provide an indication of bearing accuracy as a function of target range. A preliminary system concept, including requirements for microphones, pre-amplification and A/D conversion, signal processing, and wireless link will be developed in sufficient detail to support development of a complete prototype in Phase II
