SUBSIM Radio Room Forums - View Single Post - Why does the Towed Array reflect contacts?

Mike Abberton · 07-01-19, 11:31 AM

I believe that bearing ambiguity on the towed sensor is related to the fact that the towed array can twist under deployment so that the submarine cannot be completely sure exactly what orientation the array is in when a target is detected. While real-life use of the array is probably more complex (3D versus 2D), DW presents two opposite target bearings either of which could be the real one.

Turning the ship (or more accurately turning the array) can remove the ambiguity. Basically in the original orientation, you get two target bearings. One points to the target and the other points to a mirror bearing based on the current orientation of the array. By turning the ship and the array, you get two slightly different bearings from the array. One still points to the actual target, and the mirror now points in a completely different direction than the old mirror. Therefore, the reported bearings before and after the turn that point in the same general direction are the true target bearings, while the two that diverge significantly are the mirror bearings.

For a more detailed explanation, including pictures, check out the Redbook reference guide to TMA available here on Subsim in the Dangerous Waters downloads page.

07-01-19, 11:31 AM	#3
Mike Abberton Electrician's Mate Join Date: Jan 2011 Posts: 135 Downloads: 42 Uploads: 0	I believe that bearing ambiguity on the towed sensor is related to the fact that the towed array can twist under deployment so that the submarine cannot be completely sure exactly what orientation the array is in when a target is detected. While real-life use of the array is probably more complex (3D versus 2D), DW presents two opposite target bearings either of which could be the real one. Turning the ship (or more accurately turning the array) can remove the ambiguity. Basically in the original orientation, you get two target bearings. One points to the target and the other points to a mirror bearing based on the current orientation of the array. By turning the ship and the array, you get two slightly different bearings from the array. One still points to the actual target, and the mirror now points in a completely different direction than the old mirror. Therefore, the reported bearings before and after the turn that point in the same general direction are the true target bearings, while the two that diverge significantly are the mirror bearings. For a more detailed explanation, including pictures, check out the Redbook reference guide to TMA available here on Subsim in the Dangerous Waters downloads page.