Material Identification using Reflectivity Kernels

We will apply novel material identification algorithms, developed for the US Air Force and NRO for radar, to underwater sonar. This will yield a new capability of exploiting the material and structural composition of acoustic scatterers by providing an estimate of the full scattering kernel, enabling target differentiation and offering far more information than that contained in just the specular/diffractive response: namely scattering from internal regions and internal boundaries, and reradiation or "ringing" due to the elastic response. We will adapt the radar based algorithm to a multiple aspect angle capability for sonar, concentrating on applications to torpedo sonars to reduce false homing and other performance degrading issues. Testing will be conducted in the NUWC Transducer Calibration Facility to determine the reflectivity kernel/specular response characteristics of various objects of differing materials, using available torpedo sonar characteristic waveforms and pulse durations. A library of reflectivity kernels will be created and requirements for an APB TI will be defined. Project activities will be structured to meet NAVSEA decision gate requirements for an APB, including testing with actual sonar data and developing documentation to satisfy an APB datacall.