High-resolution target parameter estimation based on matrix mutual information and domain-transformed wideband deconvolution

High-resolution parameter estimation of underwater targets is a key technology for an active sonar. However, for wideband signals adopted by the active sonar, the Doppler frequency shift associated with the varying Doppler scale factor will cause echo spreading and distortion. This will inevitably degrade the parameter estimation performance when handling the time-domain overlapped echoes from multiple highlights. To solve the problem, this paper proposes a high-resolution parameter estimation based on matrix mutual information and domain-transformed wideband deconvolution. First, an explicit convolution model for wideband signals in the delay‑scale domain is derived. Then, a scale factor pre-estimation method based on matrix mutual information is introduced to reduce the dimensionality of the deconvolution process. Finally, the Richardson–Lucy iterative algorithm is employed to achieve high-resolution reconstruction of the target reflection function. Simulation results demonstrate that the proposed method maintains high robustness in scale estimation under low signal-to-noise ratio conditions, improves delay resolution for echoes from multiple scatterers, and effectively suppresses sidelobes. Experimental results further validate the effectiveness and feasibility of the method in achieving high-resolution target parameter estimation. This provides an effective approach for weak target detection and feature extraction in complex underwater acoustic environments.