Steering-Invariant Beamwidth Control Using Hybrid Vector-Sensor Nested Arrays in Circular-Linear Fusion

This article proposes a broadband beamforming method for underwater target radiated-noise measurement using a hybrid vector-pressure array that combines a vector-nested line subarray with a pressure uniform circular array (UCA). A hybrid measurement model is established, and a unified steering vector is derived by jointly accounting for subarray geometries and sensor responses. Simulations are conducted using a plane-wave far-field baseline and two three-path waveguide environments with varying multipath strengths. Performance is quantified by continuous-spectrum reconstruction errors over 250-2000 Hz, excluding tonal components. Results demonstrate that the vector-assisted scheme substantially mitigates ambiguity-induced leakage and yields markedly lower reconstruction errors in waveguide conditions, maintaining overall MAE/RMSE at the 5-7 dB level, lower than that of conventional and constant beamwidth (CBW), about 12-15 dB. This demonstrates improved robustness to multipath propagation and enhanced port-starboard ambiguity suppression for wideband radiated-noise reconstruction.