A comparison of forward-looking sonar design alternatives

A forward-looking sonar (FLS) is an indispensable system for most autonomous underwater vehicles (AUV). An FLS Is needed to detect obstacles or terrain that may endanger the vehicle. Sonar engineers use a variety of design approaches for various FLS applications, including those involving the AUV. The most common designs employ line arrays, cylindrical arrays, conformal arrays, and in some cases an array of multiple fixed-beam elements. The features, advantages, and disadvantages of several typical FLS design approaches are discussed and compared. Both the array design and the electronic beamforming implementations are addressed, and predictions for achievable noise-limited detection performance with selected operating frequencies and beam widths are provided.