A Hybrid Autonomous Underwater Vehicle for Acoustic Monitoring of Low-Noise Sources in Shallow Water

Acoustic monitoring of low-noise underwater sources is challenging for autonomous underwater vehicles (AUVs) in shallow water, where waveguide variability and platform self-noise reduce source detectability. This paper presents the design concept of a hybrid autonomous underwater vehicle (HAUV) for passive acoustic monitoring of such sources. The platform combines conventional AUV propulsion for deployment and transit, buoyancy-driven glider motion, and a low-noise receiving mode in which propulsion is switched off, the vehicle is anchored near the seabed, and a vector–scalar receiver (VSR) acquires the acoustic field. Functional and structural models specify the vehicle architecture, mode transitions, buoyancy and stability control, anchoring, navigation and communication, and onboard hydroacoustic processing. Holographic signal processing (HSP) transforms the frequency–time interferogram of the received field into a hologram in which the source energy is concentrated in a small region, whereas incoherent noise is spread over the hologram plane. This enables estimation of source kinematic parameters and reduces the data transmitted to a remote control center. The present work is limited to a conceptual system specification. The next steps toward implementation are hydrodynamic modeling and validation, measurement of platform self-noise, experimental validation of the hydroacoustic subsystem, embedded real-time benchmarking, and full-scale testing of the integrated platform.