Algorithms for Rapid and Accurate Depth Localization of Targets for Mine Avoidance

Under SBIR Topic N04-218, Applied Physical Sciences Corp. (APS) developed and demonstrated candidate modifications to the existing DD(X) Integrated Undersea Warfare System’s High Frequency (IUWS-HF) bow sonar signal processor that would improve the sonar’s mine-hunting capabilities in refractive, multipath environments. In Phase I, we derived a localization algorithm that correlates measured multipath arrival angle and travel time structures of target echoes with that predicted by an efficient numerical propagation model. Target localization is accomplished by searching over a scan region to find the best match between measured and modeled data and exploits the IUWS-HF system’s exceptional range and vertical angle of arrival resolution. The approach lends itself well to use in a real-time system, and can be implemented with minimal impact to the existing processor’s architecture. Here we propose a Phase II follow-on effort to continue algorithm development and performance evaluations. Our main task for Phase II will be to assess the performance of the algorithm using data collected during White Ship Trials of the IUWS-HS system. Additional tasks include developing and implementing refinements to improve overall computational efficiency and to develop a plan for integrating the algorithm into the existing sonar signal processing sequence.