A high-robustness algorithm for synthetic array using a single moving vector hydrophone

In engineering applications, non-cooperative signals lack well-defined analytical models, and existing synthetic array methodological frameworks based on single-hydrophone exhibit fundamental limitations due to their inability to resolve ambiguous signal characteristics. Moreover, traditional broadband beamforming techniques-including the incoherent subspace method and coherent subspace method-suffer from practical limitations in robustness and directional precision. To systematically address the two aforementioned challenges in a decoupled manner, this work leverages the Fourier transform's properties to achieve "time alignment" of virtual array elements in the frequency domain. In addition, the Incoherent conventional beamforming-coherent minimum variance distortionless response (ICBF-CMVDR) algorithm is proposed. The algorithm ensures excellent directivity and significantly enhances robustness. Simulation results demonstrate that the direction-of-arrival (DOA) estimation error of the proposed algorithm is merely 3° at a signal-to-noise ratio (SNR) of -20 dB, and the effective DOA estimation lower limit is extended to an SNR of -24 dB. Validation using sea trial data reveals that, when applied to the same underwater unmanned vehicle, the ICBF-CMVDR algorithm extends the duration of effective DOA estimation by more than 100 s compared to the currently implemented complex sound intensity-frequency histogram method.