Target Motion Analysis Tutorial

[Shkval]

Good one for an absolute beginner... but... you didn't show the most important stuff... the merging of bow and stern sensors/trackers data in waterfall (Master 01, Master 02 etc) and their usage in TMA. We know that crossing of bearing lines in TMA gives much more accurate picture about contact's heading, speed, distance etc.

1. First two bearings crossing gives: Exact Bearing, Approximate Distance, Unknown Speed, Unknown Course;

2. Second two bearings crossing gives: Exact Bearing, Exact Distance, Approximate Speed, Approximate Course;

3. Third two bearings crossing gives: Exact Bearing, Exact Distance, Exact Course, Very good idea of contact's speed.

It turns out that minimum time for a decent TMA solution is at least 6 minutes, the more time you have to observe contact, the better solution is! That's why the distance, i.e. first bearings crossings, is the most important part of the solution, it gives you the idea how much time you have! That is why the quietness of a sub is it's the most important feature... it comes down to "who hears who first"...

"Dangerous Waters" in difference of it's predecessor "Sub command" has one BIG flaw, the sensors (bow and towed arrays) are limited to exactly 10 NM... maybe 11 NM in clear weather, and their sensitivity is about the same... In "Sub Command" if you cannot hear a contact with bow sensors, but you can hear it with towed array you are pretty safe, and have enough time for tactical maneuvers... but that's another story...

[FPSchazly]

Originally Posted by Shkval

Good one for an absolute beginner... but... you didn't show the most important stuff... the merging of bow and stern sensors/trackers data in waterfall (Master 01, Master 02 etc) and their usage in TMA. We know that crossing of bearing lines in TMA gives much more accurate picture about contact's heading, speed, distance etc.

1. First two bearings crossing gives: Exact Bearing, Approximate Distance, Unknown Speed, Unknown Course;

2. Second two bearings crossing gives: Exact Bearing, Exact Distance, Approximate Speed, Approximate Course;

3. Third two bearings crossing gives: Exact Bearing, Exact Distance, Exact Course, Very good idea of contact's speed.

It turns out that minimum time for a decent TMA solution is at least 6 minutes, the more time you have to observe contact, the better solution is! That's why the distance, i.e. first bearings crossings, is the most important part of the solution, it gives you the idea how much time you have! That is why the quietness of a sub is it's the most important feature... it comes down to "who hears who first"...

"Dangerous Waters" in difference of it's predecessor "Sub command" has one BIG flaw, the sensors (bow and towed arrays) are limited to exactly 10 NM... maybe 11 NM in clear weather, and their sensitivity is about the same... In "Sub Command" if you cannot hear a contact with bow sensors, but you can hear it with towed array you are pretty safe, and have enough time for tactical maneuvers... but that's another story...

That's for another tutorial My goal here is baby steps. There's a lot to learn and I don't want to swamp people who have no idea what I'm doing (yet). But thank you for the input!

Also, the trackers for that need to update at the same time to get a reliable intersect in the TMA. More often than not, the intersect is not completely correct when you look at it on the TMA. On the other hand, the bearings to those contacts will update continuously on the Nav Map, as long as they have trackers, and that intersect does work in my experience.

[Shkval]

Originally Posted by FPSchazly

Also, the trackers for that need to update at the same time to get a reliable intersect in the TMA.

Well... that's the catch... to track a contact with multiple sources of informations....great way for tracking surface contacts at very long range (not possible in DW because of aforementioned limitation of sensors), was merging of towed array LOB's and passive radar mast LOB's... of course you will have to bob the submarine up and down every two minutes between, let's say 40 meters, and radar mast depth... a bit cumbersome... but veeery efficient.

Also, don't trust your "one tool" (i.e. for example, only towed array) solutions... because you may get a nasty surprise when you add another LOB's source... he can be much much closer than you imagined... this usually leads to biting enemy torpedo...

One more thing... this whole thing doesn't work for Kilo class... they don't have towed array and their sensors are pretty weak... you'll have to use the "old fashion" way of periscope observing...

[banryu79]

Originally Posted by Shkval

Also, don't trust your "one tool" (i.e. for example, only towed array) solutions... because you may get a nasty surprise when you add another LOB's source... he can be much much closer than you imagined... this usually leads to biting enemy torpedo...

Well, in that case you can play it "safe" with a lag LOS... You can nail down the minimum range of your contact if I had understood it right.

[Shkval]

What is a lag LOS? Turning into a contact?

[banryu79]

Originally Posted by Shkval

What is a lag LOS? Turning into a contact?

I've red it here in the TACMAN:
http://www.subsim.com/radioroom/down...?do=file&id=91

very useful knowledge


P.S.: I think that turning directly to a contanc put ownship in a "point" LOS (btw LOS means Line Of Sound). There are different types of LOS, the most important, if I understand correctly the stuff I red in TACMAN and other sources about manual TMA, are three:
- lead LOS
- overlead LOS
- lag LOS

So if you could switch form overlead to lag or from lag to overlead (changing course and/or speed) you can nail down both the minimum and maximum range...

In overlead and lag you have a situation in which your LOBs converge and cross in a point. If you are in a overlead LOS the crossing point is the maximum possible range of the contact, else if you are on a lag LOS the crossing point is the minimum possible range.

[Shkval]

Ahhh... lead and lag course... multiple zig-zag's tricks... never liked it... too much time needed for usable solution...

[banryu79]

Originally Posted by Shkval

"Dangerous Waters" in difference of it's predecessor "Sub command" has one BIG flaw, the sensors (bow and towed arrays) are limited to exactly 10 NM... maybe 11 NM in clear weather, and their sensitivity is about the same... In "Sub Command" if you cannot hear a contact with bow sensors, but you can hear it with towed array you are pretty safe, and have enough time for tactical maneuvers... but that's another story...

And that's the #1 reason I use LWAMI and LWAMI is such a fantastic work!
This cap is removed, the acoustical model (or, if I understood well, the parameter set that model the behaviour of the acoustical model) is polished and the specific platforms acoustical profiles (Speed VS Noise, aso dependant on the type of propusion, nuclear, diesel-electric...) are adjust for all and each platform (and LWAMI have some new platforms in its database than stock DW).
This is the major (gameplay wise) difference between LWAMI and stock DW and... it rocks!