A generalized linear filtering approach for sonar receivers.

Abstract

Active sonar systems operating in realistic environments face the challenge of simultaneously detecting and resolving multiple targets. Receiver signal‐to‐noise ratio gain and main‐lobe width of the receiver response to the transmitted signal limit the detection and resolution capability of an active sonar receiver, respectively. A matched filter is commonly used for target detection to exploit its optimal detection property. Theoretically, an inverse filter achieves optimal resolution and can be used to resolve targets. In practice, the inverse filter is difficult to implement and requires unrealistically high signal‐to‐noise ratio to perform well. For an active sonar receiver operating in a cluttered environment with closely spaced targets, a matched filter might not resolve some targets and an inverse filter could not detect some targets. For such environments, a generalized linear filtering approach is proposed. This new approach combines the matched and inverse filter properties in a controlled manner to achieve smooth trade off between detection and resolution. In simulation, the generalized linear filter output is compared with the matched and inverse filter outputs to demonstrate the advantages of the proposed filter. In addition, receiver operating characteristics of the filters confirm the improved performance of the generalized linear filter. [Work funded by ONR Code 321US.]