Rethinking Forward-Looking Sonar for AUV´s: Combining Horizontal Beamforming with Vertical Angle-of-Arrival Estimation

This paper presents a new approach to forward-looking sonar (FLS) design for autonomous underwater vehicles (AUV´s). The approach accommodates obstacle detection, bathymetric profiling and high resolution B-scan imaging and is based on the concept of combining horizontal beamforming with vertical angle-of-arrival estimation. Justification for the approach is provided in the form of a description of the FLS functional requirements and is followed with a short discussion of the benefits and challenges associated with an angle-of-arrival estimation based approach. A small, low power, prototype FLS is then presented along with raw bathymetry and target localization results for short range operation over a 45deg horizontal field-of-view in very shallow water inside a test tank. Results establish that the proposed approach is both well suited to the stated functional requirements and at the same time is practical in terms of power consumption and size.