Platform Noise Reduction

For acoustic sensors to have sufficient detection ranges on future combat systems, a platform noise reduction system that achieves near ambient noise levels is needed. The overall objective of this project is to demonstrate the feasibility of platformnoise reduction using noise cancellation sensors and algorithms. During Phase I Signal Systems Corporation will collect data on either a HMMWV or an unmanned vehicle. We will determine noise sources, and the spatial coherence of the noise field underdifferent platform operating conditions. We will investigate new acoustic array designs with improved platform noise suppression; examine noise reduction techniques applicable to moving conditions; and demonstrate (off-line) broadband noise reduction. Wewill develop a preliminary design for a high frequency noise reduction system applicable to acoustic shock wave processing. Technical results included in the Phase I effort are noise reduction versus vehicle speed; noise reduction versus algorithmapproach; noise reduction versus number of array and reference sensors, and self-noise classification features that discriminate between near and far-field acoustic signatures. The results of our Phase I effort will have addressed the critical risk areasof this project and provide a solid foundation for a real-time prototype effort in Phase II.Our approach will enable maximum platform noise reduction onboard future combat vehicles, such as reconnaissance unmanned vehicles. By making acoustic sensorseffective, we can provide an all-weather, all-time surveillance capability that helps to queue infrared and visual sensors without the cost, power and weight associated with radar processors. This technology will also improve speech recognition performancein the wireless and handheld information appliance products.