Research on the Design and Implementation of the Receiving Circuit for Underwater Acoustic Long Baseline Positioning Systems

Underwater acoustic long baseline (\(LBL\)) positioning systems have wide-ranging applications in marine resource development, utilization, and protection. The accuracy of \(LBL\) systems depends significantly on the precision of time-delay estimation, which is influenced by the performance of analog conditioning circuits. This study introduces two analog receiving conditioning circuit solutions for underwater acoustic \(LBL\) systems to address dynamic ranging scenarios. The research focuses on designing essential circuit modules, such as signal acquisition, pre-amplification, filtering, and signal digitization. Through simulation analysis, circuit parameters like gain, noise suppression, and frequency response are optimized to extract valid signals efficiently amidst complex underwater noise environments. Furthermore, the study delves into filter design, specifically the selection of cutoff frequencies for bandpass filters, to effectively separate low-frequency noise and improve system anti-interference capabilities. The stability and reliability of the receiving conditioning circuit in practical applications are confirmed through hardware implementation.