Description and Evaluation of a Four-Channel, Coherent 100-kHz Sidescan Sonar
Abstract
This report documents the design and features of a new, four-channel, coherent 100-kHz sidescan sonar system developed in a collaboration between Defence R&D Canada-Atlantic and the Institute of Ocean Sciences (Fisheries & Ocean Canada). This system supports four separate 100-kHz sidescan transducers, with coherent in-phase and quadrature sampling of each channel at 20,000 samples per second. The system has the capability to transmit uncoded, phase-modulated Barker-coded, and swept-FM (chirp) pulse types, with user selectable pulse-lengths up to 10 ms. As part of the acceptance tests, several sidescan sonar applications were demonstrated, including conventional and multi-aspect-angle sidescan, seabed bathymetry through interferometric processing, and the use of chirp pulses. The primary tests were conducted from a small boat in the vicinity of Esquimalt, B.C., in April, 2002. The relatively large horizontal beam-width (3 degrees) of the transducers was found to provide insufficient along-track resolution for reliable seabed mine detection, particularly when compared to very high-frequency imaging sonars such as the Klein 5500. However, the sonar demonstrated a much greater operational range, in excess of 200 m per side. The use of port and starboard interferometric dipoles was able to map the across-track seabed slope at ranges up to 200 m in roughly 20 m water depth. Measured backscatter frequency spectra were found to have nearly identical frequency content to reference chirp-pulse spectra.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2004
- Accession Number
- ADA436385
Entities
People
- Mark V. Trevorrow
- Vincent Myers
Organizations
- Defence Research and Development Canada