Self Noise Influence on Towed Array Bearings Close to the Direction of the TowingShip

摘要

Performance of towed arrays is often limited by a 'blind zone' in the forwarddirection due to the noise of the towing ship. In order to understand the effect of such a blind zone, this report investigates the extent of the blind zone pattern using various array configurations keeping the towing ship noise level fixed. Sonars with three different frequencies (1.4, 1.8 and 2.0kHz) and their respective number of hydrophones (48.32, 128) will be simulated using the Generic Sonar Model. The longer the array is, the narrower the blind zones will be. The noise level in the blind zone bearing region also is reduced for soft bottoms as is seen when going from MGS1 to MGS3 and further to MGS5 bottom type. The sea state dependent ambient noise has of course stronger influence when the self noise is low. For a rather quiet ship it was shown that the extent of the blind zone is of particular interest for sea states lower than SS3.