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| BOSS I | |||||||||||||||||||||||||||
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| INTRODUCTION | |||||||||||||||||||||||||||
| Designed to scan for objects buried in the sea floor, the BOSS I generates images of pipe and cable sections and ordinance buried in sand. The sonar operates by illuminating a broad swath of the seabed using a line array of acoustic projectors while acoustic backscattering from the illuminated sediment volume is measured with a planar hydrophone array. The line transmitter performs along track beamsteering to improve the SNR of buried target images by illumination. The output of the planar-hydrophone array undergoes nearfield focusing which allows the sonar to operate near the seabed where target images have the highest SNR and resolution. The nearfield focusing reduces scattering noise by approximately 12dB, an improvement measured by comparing the SNR of target echoes in single channel data with the SNR of buried target in the focused imagery. Plan and side views of the seabed generated from a three-dimensional matrix of focused data provide the position and burial depth of targets covered by sand off the coast of Hawaii. An energy detector automatically locates targets in the focused image data. | For a complete view of the Buried Object Scanning Sonar paper published on IEEE Journal of Oceanic Engineering, VOL 26, No. 4, October 2004, please click to download the .pdf version | ||||||||||||||||||||||||||
| SYSTEM COMPONENTS | |||||||||||||||||||||||||||
| System Overview
The BOSS consists of a towed vehicle, a data and power cable, and a topside sonar processor. The towed vehicle contains the acoustic arrays and an underwater canister for transmitter and receiver electronincs, data acquisition computer and motion sensor. A block diagram of the software is show in the figure below. The system currently uses 7 Pentium processors. In the underwater canister, a Pentium II class computer along with two TMS320 DSP processor cards handle the real-time acquisition of 32 channels of hydrophone data and generate chirp pulses for the six acoustic projectors in the line array. |
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| DATA COLLECTED | |||||||||||||||||||||||||||
| Sonar displays for transmitter steering angles of -8.7 and 13.1 deg | |||||||||||||||||||||||||||
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