Assigning trackers: NB vs. BB.

[Troels K]

Hi Guys

My starting procedure on a new mission is first to scan the SA/TA BB (US subs) to get a rough overview of the tactical situation. Then I go the NB TA display to get a more detailed picture of the surrounding traffic and to begin the initial classification using the NB signature. At this point I do not assign trackers in the NB station; instead I’m going back to the BB sonar where I’m assigning trackers to targets with a sufficient SNR on the memorized bearings (for DEMON use). Targets with low SNR are marked in the NB station.

My questions are now:
Is there a difference in bearing accuracy (or others things as well) when the tracker is assigning to a contact line in the BB display compared to assigning a tracker to a specific frequency line in the NB display.


Furthermore:
Does it matter which frequency line I’m assigning the tracker to in the NB display?
Due to bearing scatter or variation in signal strength.

I'm playing with patch v1.03 and LWAMI 3.02

Thanks

Troels

[SeaQueen]

Originally Posted by Troels K

My questions are now:
Is there a difference in bearing accuracy (or others things as well) when the tracker is assigning to a contact line in the BB display compared to assigning a tracker to a specific frequency line in the NB display.

Not that I've noticed. I don't worry too much about an individual bearing's accuracy so long as it's reasonably in agreement with the others. The only time it's really a huge issue is when targets are so far away that they're not worrisome, or the towed array hasn't stabilized. As long as you can get a reasonably good estimate of bearing rate, then you can get a reasonably accurate range. When you measure bearing rate, you are essentially averaging over time, so the small uncertainties in the bearing over time average out. It's impossible to be perfect, but you can get close enough that a torpedo can do the rest of the work for you.

Does it matter which frequency line I’m assigning the tracker to in the NB display?
Due to bearing scatter or variation in signal strength.

Not that I've noticed. If the signal is that weak then it's probably far away, particularly if it's on the towed array. If you get a weak signal on the sphere, be worried because the sphere indicates a target is probably quite close.

The best way to be certain if a target is near or far is the bearing rate. If you have a weak signal but a high bearing rate, then it's probably a very quiet target that is very close to you. If it's a weak signal and a low bearing rate, then it's probably sufficiently far away that it'd be difficult to get an accurate range, and isn't of concern anyhow. In that case you just have to keep an eye on it, because over time it might draw closer and the bearing rate will increase accordingly.

The one time I worry about low bearing rate targets is if I turn and the bearing rate blows up. If that's the case then the target was on a collision course. I've had that happen a couple times against quiet targets like SSBNs.

[Troels K]

Thanks for your reply SeaQueen

Then I don’t have to consider which sonar (NB or BB) I’m assigning the tracker in.


Troels

[sonar732]

Originally Posted by Troels K

Thanks for your reply SeaQueen

Then I don’t have to consider which sonar (NB or BB) I’m assigning the tracker in.


Troels

Just remember that if you utilize the DEMON, you have to assign in BB first.

[Troels K]

Originally Posted by sonar732

Just remember that if you utilize the DEMON, you have to assign in BB first.

You are right; I have experienced some difficulties with getting a DEMON display when the tracker was first assigned to a target in the NB station. I still have to consider this issue.

Sincerely

Troels