Non-collinear Wave-front Curvature Range Measurement

Present submarine passive sonars utilize collinearly located sensors to obtain target range by the method of Wavefront Curvature Ranging (WCR). The requirement for sensor collinearity creates difficult and costly installation problems. Thus, the goal ofthe proposed effort is to demonstrate the technical feasibility of using non-collinear sensors and a WCR method to obtain range, bearing and D/E estimates of incoming threat targets in the frequency range of 1 kHz to 100 kHz. The feasibility will addressthe following issues: 1) basic physics and geometry, including range, accuracy, sensor number, location; 2) acoustics, signal and noise, including time delay estimation, signal properties, sensor properties, shallow water environments, sensor backingimpedance; and 3) advanced signal processing techniques. Also, practical system issues such as optimizing the use of onboard sensors, system architecture and integration, and cost-benefit tradeoffs will be evaluated. A preliminary design for acost-effective, reliable, and robust acoustic intercept (AI) system will be developed. The system will likely utilize the existing AN/WSQ-9 sensors working in conjunction with other sensors. A plan to demonstrate the system feasibility will be providedfor the Phase II effort. The end benefit is a significantly improved Acoustic Intercept System for the protection of submarines.