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1975: Vol. LII, No. 1

Side Scan Sonar for Hydrography - An Evaluation by the Canadian Hydrographic Service

August 7, 2015


Hydrographic surveys have improved in accuracy and efficiency over the last few decades with advances in electronics and data processing. Electronic positioning systems with automatic data loggers now make it possible to survey accurately at greater speed. Improved data processing systems eliminate the time-consuming, laborious task of scaling and plotting. The modern surveyor, however, is still plagued with the lack of knowledge of what lies between his sounding lines. Sonar developments promise to improve this situation as commercial equipment becomes available. Omnidirectional scanning sonars can view large areas of the bottom and display the features on a CRT display; searchlight type sonars yield range, azimuth and depression angle with the potential of making depth measurements far removed from the survey vessel; multiple beam sonars simultaneously sound sectors along the vessel path and side-looking sonars delineate features of the bottom on wide swaths, either side of the survey craft. This paper deals with the latter type, the dual side-scan sonar, specifically the type produced by E.G. & G. and Klein Associates of the United States. The principles of operation are presented, the results of an evaluation are given, and the use of the sonar over a field survey season is outlined.