False contacts in TA

Henson · 02-22-06, 03:42 PM

Try not to think of the towed array as hearing sounds in a 360 degree environment like the spherical array does. The FFG's TA broadband display actually does a much better job of modeling how the TA really hears things, that is Front to Back.

Let's say you are heading north and have a spherical array contact bearing 030. On the FFG towed array (which most closely models a real display), that contact would be about halfway up the front section of the array on relative bearing of 030...OR 330. The array can only hear front to back (180 degrees vice 360), so it has no way of knowing which side the contact is actually on until it is turned. The procedure in the manual for resolving bearing ambiguity is much closer to the way it is done on a real TA platform, including submarines. If the contact draws up the array (or forward, whichever you prefer), that means the TA turned towards the contact. Draw a birds-eye perspective picture of that and it will make sense to you.

The reason it shows two contacts instead of one on the submarine platforms has always been a mystery to me. I suspect that it was a decision made when writing 688I and the programmers just decided it would be too much of a hassle to fix in subsequent new releases. Basically, the current DW sub display is just two TA displays connected to each other, one going from front to back, and then returning back to front. If you think in those terms it will help. If you want the real in-depth theory of it, look to the FFGs TACTASS.

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02-22-06, 03:42 PM	#1
Henson Planesman Join Date: Feb 2006 Posts: 185 Downloads: 13 Uploads: 0	Try not to think of the towed array as hearing sounds in a 360 degree environment like the spherical array does. The FFG's TA broadband display actually does a much better job of modeling how the TA really hears things, that is Front to Back. Let's say you are heading north and have a spherical array contact bearing 030. On the FFG towed array (which most closely models a real display), that contact would be about halfway up the front section of the array on relative bearing of 030...OR 330. The array can only hear front to back (180 degrees vice 360), so it has no way of knowing which side the contact is actually on until it is turned. The procedure in the manual for resolving bearing ambiguity is much closer to the way it is done on a real TA platform, including submarines. If the contact draws up the array (or forward, whichever you prefer), that means the TA turned towards the contact. Draw a birds-eye perspective picture of that and it will make sense to you. The reason it shows two contacts instead of one on the submarine platforms has always been a mystery to me. I suspect that it was a decision made when writing 688I and the programmers just decided it would be too much of a hassle to fix in subsequent new releases. Basically, the current DW sub display is just two TA displays connected to each other, one going from front to back, and then returning back to front. If you think in those terms it will help. If you want the real in-depth theory of it, look to the FFGs TACTASS.