Use of the towship for assessing towed-array performance and analyzing data quality

Abstract

A series of relatively simple tests are presented and discussed, which used in conjunction with the noise received from the towship, can be used in real time to assess the performance of a towed array and the quality of the acoustic data. One test constitutes a simple, yet thorough, relative amplitude calibration of the sonar system. Examples from actual measurement situations are given to illustrate the utility of these tests in indicating the existence of problems and providing clues to their sources. Results suggest that problems which affect array performance and degrade data quality occur more often that might be expected. Once the problem is corrected, however, measurements can ofttimes be carried out with a near-perfect system. Measured side-lobe suppression levels in excess of 40 dB and in some cases in excess of 50 dB are not uncommon.