Fast Propagation Modeling for Multi-static Sonars Navy SBIR FY2005.1 Sol No.: Navy SBIR FY2005.1 Topic No.: N05-044 Topic Title: Fast Propagation Modeling for Multi-static Sonars Proposal No.: N051-044-1154 Firm: Applied Physical Sciences Corp. 2 State Street Suite 300 New London, Connecticut 06320-6356 Contact: Joseph Edwards Phone: (860) 440-3253 Web Site: www.aphysci.com Abstract: The US Navy's new DD(X) destroyer, currently under design, is expected to serve not only as an independent battlespace resource but also as a hub of a network of environmental sensors and sonar platforms. In this role, the DD(X) crew is responsible for deciding the distribution of assets needed to best accomplish the objectives of the current mission. Due to the environmental sensitivity of multi-static systems, an accurate numerical solution in support of multi-static planning often cannot be accomplished in a timely manner with onboard computing assets. In this proposal, a method is outlined to provide an extremely fast and robust simulation capability to allow a better characterization of the acoustic propagation in the local area. An accurate, real-time model is essential to enable optimum placement and processing of multi-static offboard sensors in challenging operational areas. The method innovatively combines several approximations and efficiency gains that are individually described in the open literature and applied by entities such as NATO and NRL. The tool represents all major features of the propagation, including range dependence, attenuation and waveguide Doppler shifts for the source, target and receiver, and is able to evolve in time as the situational awareness evolves. Benefits: If successful, the proposed research would provide a significant advancement in the effective placement and processing of multi-static offboard sensors. The means to this end is through a long-needed advancement in the practical application of acoustic modeling in real-time operations. Acoustic modeling has been developed for several decades as a tool for experts in a laboratory, and at sea for very discrete line-of-bearing analysis. Efficiency gains and technological advancements have been realized so that relatively simple 2-D transmission loss calculations can be performed in less than a second. This improvement in speed has moved the acoustic modeling domain from the shore laboratory to research ship laboratories, in which experiments can be planned or analyzed over the course of hours to days. In addition to the speed gains, the experience of the acoustic modeling community has led to a near automation of the computation in typical situations, or rules of thumb for deciding difficult parameters. The convergence of these two paths, albeit perhaps long in the future, is the full on-board acoustic awareness of autonomous sonar platforms. In the meantime, the reduction of complexity and computation time is of interest to improve performance for real-time Navy operations, as proposed in this work, as well as to support academic research experiments and commercial shipping and fishing operations. The capability of the proposed modeling framework to dynamically evolve has particular benefits in cases in which environmental monitoring information is available, which currently would apply only to Navy operations and academic research experiments. With the future proposed ocean monitoring systems, however, this is likely to change in the not too distant future. Return