Abstract
Active sonar systems perform range estimation using pulse compression, where a high-bandwidth pulse is transmitted, and echoes are typically processed with matched filters. Matched filters optimize output signal-to-noise ratio (SNR) for a single target in white noise while range resolution is limited by the pulse bandwidth. This work explores methods to adaptively improve range resolution over the matched filter. Sharma and Buck (2011) proposed the variable resolution and detection receiver (VRDR), which adjusts its range resolution between the matched filter and the inverse filter with one parameter, trading off detection gain for range resolution. In practice, the VRDR requires prior knowledge of the target and noise background to choose the best resolution and detection gain tradeoff. A new receiver is proposed to blend VRDR receivers with different detection and resolution tradeoffs to adapt to the environment. Each VRDR receiver output is weighted based on performance, using a mixture of experts' approach inspired by universal linear prediction [Singer and Feder, 1999] to implement the blending and minimize the regret of using a fixed individual VRDR filter. Preliminary results show the blended VRDR can improve range resolution while maintaining detection performance for many scenarios by adapting to the background SNR. [Work supported by NUWCDIVNPT.]