Conventional active control approaches in underwater environments primarily focus on one- or two-dimensional suppression along the incident direction. It often generates pronounced echo highlights in non-controlled regions and can hardly meet the practical requirements under bistatic/multistatic detection scenarios. A thin, lightweight, and high-pressure-resistant integrated active-passive acoustic coating was designed for omnidirectional stealth of acoustic scattering from three-dimensional surfaces of underwater vehicles. Based on the bare-hull Benchmark submarine model, acoustic modulation was implemented through a combined active noise control and phased-array acoustic beamforming strategy. The design for omnidirectional active echo suppression was validated through numerical simulations and experiments. Full spatial coverage in both circumferential and radial directions was considered, with special emphasis on solving the difficult-to-suppress scattering from the bow region. Within the 300–1200 Hz low-frequency band, the target strength reduction exceeds 20 dB in the incident direction, while the spatially averaged enhancement of the new echo highlights remains below 0.7 dB. All these effects can be achieved within a 12° incident angle bandwidth at low frequencies. The proposed framework provides a feasible modular-layout design and control methodology for omnidirectional active acoustic control of underwater vehicles in the broadband, multi-azimuth detection environments.
Wang et al. (Fri,) studied this question.