Time Domain Model Beamforming for a Near Vertical Acoustic Array

摘要

Ocean acoustic tomography permits the mapping of various properties of a body ofwater through indirect means. The technique utilizes travel time variations for an acoustic signal to determine the structure of the ocean medium via inverse mathematical methods. The scale of any tomography experiment is fundamentally limited by the signal to noise ratio at the receiver. Through the use of a near vertical acoustic array, normal mode modeling of the local environment and a modal beamformer, array gains are possible which greatly extend the maximum separation between source and receiver. Additionally, the technique provides temporal resolution of the modal components of the arriving signal. A time domain modal beamformer for a near vertical acoustic array has been developed. It has realized a nominal array gain of 6 dB for the Heard Island Experiment vertical array deployed off California. The primary obstacle to the technique remains inadequate array geometry description.