Frequency Scanned Phased Array Sonar

This Phase I proposal is to establish the feasibility of developing a near-forward looking sonar to enhance the near-nadir bottom survey and obstacle avoidance capability for small undersea unmanned vehicles (UUV) such as REMUS. The proposed approach isa relatively simple Frequency Scanned Phased-Array (FSPA) sonar that takes advantage of the frequency dependence of the direction of phased-array beams to form multiple beams within a forward sector, mapping range and angle into time-frequency space. TheFSPA approach has the flexibility to be implemented in several different beam geometry configurations, ranging from small angle sector to full two-axes coverage. The simple implementation will be practical and affordable for use in small UUV's. DuringPhase I we will conceptually configure a FSPA sonar to the UUV requirements, use theoretical analysis aided by experiments to validate the concept, identify the performance limitations, and specify a prototype to be developed in Phase II. Theanticipated benefits of the of Phase I and II development is availability of a prototype sonar practical for use on small UUV's to enhance the near-nadir bottom survey and obstacle avoidance capability. Potential commercial applications include use on awide range of commercial and military UUV's involved in bottom bathymetry mapping and operating in environments with obstacles.