Cyclostationary Doppler Estimation in Multiscale-Multilag Underwater Channels for Precise Acoustic Navigation

Accurate Doppler estimation are a critical challenge in underwater acoustic navigation due to the complex propagation environment, motion-induced Doppler shifts, and multipath effects that degrade navigation accuracy. Traditional methods, which often assume constant Doppler shifts, struggles to handle the dynamic and high-mobility scenarios common in underwater environments. Moreover, the time-varying nature of underwater channels, coupled with the multiscale-multilag (MSML) characteristics, complicate the estimation process. Motivated by the limitations of these approaches, this work introduces a novel framework that leverages the cyclostationary properties of communication signals for Doppler estimation in MSML underwater channels. By modeling the channel-induced time-varying Doppler as a time-warped cyclostationary process, the proposed method captures both velocity and acceleration dependencies, enabling more precise Doppler scale estimation. This cyclostationary-based approach are particularly suited for both wideband and narrowband signals, and it operates without requiring pilot overhead, making it highly effective in covert and non-cooperative scenarios. Extensive simulations validates the robustness of this technique especially in multipath-rich and high-mobility environments. The proposed method greatly enhances underwater navigation accuracy and reliability, offering promising applications in ocean exploration, underwater robotics, and secure military communications.