Exploring autoproduct fields in three-dimensional acoustic environments using vertical and horizontal array configurations: Simulations and experiments

Acoustic remote sensing and source localization are fundamental topics in underwater acoustics, with applications in navigation, environmental monitoring, and surveillance. Traditional signal-processing methods typically rely on frequencies within a recording’s bandwidth. Recent advances have shown that environmental and source information can also be extracted at frequencies outside this bandwidth using frequency-difference and frequency-sum autoproducts [Worthmann and Dowling (2017), J. Acoust. Soc. Am., 141, 4579–4590]. Previous autoproduct studies have primarily examined two-dimensional sound fields. This work presents simulation and experimental autoproduct-based source localization using both vertical-array and horizontal-array recordings, with the horizontal array aligned parallel to an added vertical reflecting surface. Varying array orientation enables comparison across geometries, improving understanding of complex three-dimensional acoustic environments and supporting the experimental work. Recordings were collected in a fully three-dimensional four-ray-path acoustic field generated in a Lloyd’s mirror environment augmented with a vertical reflector. Experiments were conducted in a 1.07-m diameter freshwater tank using short Gaussian-enveloped pulses with a 40–150-kHz nominal bandwidth. Time gating suppressed sidewall and bottom reflections. Simulated and experimental localization results are compared. [Work sponsored by ONR.]