Stupid questions about ... what I have read and studied.
 

As I said before, after more than 2 years absent from the community, I need to revise many I have read before.

I still do not understand the meaning of the TMA instrument. The concept is to compute the range, speed and course of a track that is straight forward. Here is what I do not understand: the track is moving, how does the TMA work to lock-on to a track.

Using the 2D map, I can easily classify an unknown object as "hostile" thus allowing myself to assign it as a target to my weapons. So why do I have to go through the procedure to "classify" the target using "Hull/Conformal" sonar?

Ok i think your talking about 2 different things here, If ive misunderstood forgive me.

TMA is a slow proccess of bringing different peices of information together in order to work out a targets course, speed and range.

To begin with you have one peice of information, its bearing. Depending on its distance you will be able to work out from NB traces exactly what it is you are picking up. Ie surface, sub, whatever. Also you may be able to work out from the NB excatly what class it is.

Now once you have that information, its best to classify this on the NAV map so you can keep a picture of what is going on.

Also once you have a contacts class (and a broadband source) you can perform speed analysis via your demon.

Having the speed of the contact greatly helps the TMA equation.

There are other ways of finding out a contacts ID. If you have a broadband trace, check the demon and count how many blades are showing (be careful if its a faint contact they might not all show). If they are pinging you with active you can get a rough idea of the class from the frequency displayed in active intercept. And finally you have ESM and Periscope.

So in answer to your question, contact identification goes something like this.

1) Try to work out a contacts Type and class from NB or any other availible sources.

2) Update the Nav map with the information you have at hand.

3) If you have the contacts class, perform demon to ascertain speed.

4) Refine TMA for a good solution.

Hope that helps.

Re: Stupid questions about ... what I have read and studied.
 

You dont have to... you can guess and shoot at everything, sinking all those neutral yachts and fishing boats.. if it is your desire ;)

Re: Stupid questions about ... what I have read and studied.
 

That's why I am asking the above questions.

Sorry SquidB, I don't get all you have explained to me. What does NB stand for? I don't think in reality one will go to periscope depth for identification? That's for surface targets only isn't it?

I still do not understand the steps I am required to perform to complete an identification.

How many times I have to compute for a solution before I get a lock on to target? Does it automatically lock-on a target like in the air you lock on a target with just 1 click away?

By the way, do you guys remove AutoCrew every time you run a mission?

Oooh this one wont be easy, it seems like you are somewhat...missing the whole point? :) (or I am missing yours :doh: ).

1) Ok, killing neutral ships is a bad bad thing, you will get penalized for that, sometimes it can even mean a mission failure, not to mention the poor helpless innocent /et cetera/ people there ;)

2) NB stands for Narrow Band, it is a type of sonar that allows target classification by its sound profile (distinct frequencies the target emits).

3) What you mean by "lock on to target"? Actually, torpedoes, unlike AA missiles do not lock onto their target before they are fired. They are simply launched in the target's direction, and at some point (their enable range) they activate their sonars, seeking for targets...if they find something, they will go after it.

Zerogreat,

I just returned from a 2 hours "training" mission. No luck! :(

The most frustrating is that the "true" position of the track is far away from the contact(i.e. the yelow mask representation).

I retried 3 times, with random position of the target. At the beginning, it's always sweet that I could hear my FIRST contact and asked sonar to start the track. Luckily, I got the contact from the broadband Sphere sonar. That was a civilian Tanker. I went into the Sonar Demon but I do not know how to make things out. When I changed the civilian to a warship, a FFG actually, I don't get that distinct stripe from the broadband sonar, but instead I got contact information from the Active Intercept. That's fine as long as I can get a contact. But what confused me was that why contact information can be found in broadband sonar when it is a civilian ship whereas for a frigate, no information can be obtained from the broadband sonar?

THats because of the nois a tanker made, and a FFG don't. War ships are more made for silence. For that FFG, go to NB and scan the band for a 60 hrtz line.
It have to be within 10 nm I think.

I was just about to raise another questions. Nearly all documentation I am reading mention frequencies, and the range of frequencies each type of sonar is capable of handling.

Now tell me please, how much I need to know about frequencies? And what are they?

God, flying a fighter is much much easier!

My english is lacking to explain you what a frequency is.... eh.. high pitched noises are high frequency and low pitched noises are low frequency. For instance the ships/subs electrical system is 60 (USA) or 50 (Russia and otres) Hertz, which is low frequency... and that is best detectable by the towed array.

For the gameplay, each platform, when you look at it in NarrowBand station, emits i think 5 (it can be less, depends on the sensor used, distance etc.) distinct frequencies - they are depicted as lines. Now u use the database to list known platforms and their sonar profiles, and if you see the lines from database to match those you get from NB sonar, you have likely identified the target :)

That is, because when you assign a sonar tracker, it gives you only target's bearing, NOT range.... you have to use TMA to get target's range. But doing TMA is not actually easy, after years of playing subsims i learned it relatively good, but it is matter of time :)

Oh, for Christ sake, then I have to remember all of the frequencies related to components of every vessels..? Now, I don't have that much memory in my mind. Besides, I run missions for simulation sake, I am expecting less serious experience. Is there an easier way?

So TMA is not reliable? It is error prone? OMG! What about the Sonar Demon? I take it that you can figure out quite much information for identification purpose using the various meters and instruments in there. HOW?

No, you dont have to remember the frequencies, they are displayed in the NB station :) I will post a picture to explain what i mean :)

Sonar Demon is for getting target's speed. You ahve to identify the target first, the look into USNI database (in DW) and see its TPK (turns per knot) value. Most submarines have TPK of 7. Then in the Demon station, select the appriopriate contact (it must have a tracker assigned in broadband) and you will see waterfall of lines... enter the TPK value and align cursor wtih tle LEFTMOST line, and you will get target's speed :)

For TMA - its just a geometry :) If you know the targets speed enter it, and then try to place the "ruler" in such way that each tick on teh ruler is aligned with appropriate line ... you can also check the "dot stack" in top left corner. If all the little dots are on the line, your solution is probably correct. But if you dont know the target's speed there may be infinite solutions! In such case, change your course, and eventually then there will be only one (geometry, huh :) ).

Here, the pictures should be pretty self explanatory, i think :)

http://zerogreat.wz.cz/NB1.jpg

http://zerogreat.wz.cz/NB2.jpg

THANKS! Your great help is warmly appreciated. I shall get back to you after compilation of the information. It's very kind of you. :up:

Yep it is, because you have a window outside of the plane. ;)

Ive been a flightsim junkie for more than i care to remember. The thing about DW is that its a complex and rewarding sim that takes time to get used to.

Trust me it will make sense, and the feeling of accomplishment when you get a TMA solution right is great. Simply because you know youve done someting thats nigh on impossible.

Hang in there and DW will give your rewards by the bucket :sunny:

Zerogreat,

I have to organize before I get back to you. First, very much thank you. Neither the SC nor the DW manuals provide such detailed example as to how to identify a contact. Other documentations don't provide information in such details.

This is the problem throughout the course of completing or learning from a mission. There are many tiny little things which even now, from you I know how to operate; I still don't know exactly what they are. Your effort is such keen that I am touched. Thanks once again.

Now here are my questions:

So, we always talking about frequencies, frequencies, they are actually a continuous "noise" from some sound sources. It could be a whale, it could be an earth quake or a hungry giant Octopussy do I understand it right?

Then like using one of our mixers or equalizers on our desktop or laptop, you can raise or lower one or more of the available frequencies to adjust the music output to suit our taste simply because they are a "noise" source. So the 5 frequencies that you detected in the example is somehow like music, right?

What I want to ask is that on the smaller NB display, roughly between bearing 0 and 90, there is a trough, does it correspond to that part of my boat which has no sonar coverage? Also, how do I tell from the pattern of the waves that there is a contact? Should a contact be found from the pattern, those frequencies will come out to the larger display?

Another question is about torpedo. After firing a torpedo, it actually goes unguided. We have to manage its direction so it goes towards the suspected target. Now if the target's true depth is say 300ft, but our torpedo was launch at 1,200ft, how does it know the target is 900ft above? How do we home-in a torpedo?

What are layers? Can we move between layers to hide ourselves or even evade from incoming torpedoes?

In fact, I wonder why there are no windows in a sub? With a window, we can see each other. :-j

No, seriously. I wonder why there are no Infra-Red detector. Using InfraRed detector, we can still remain stealthy.

Hope nobody minds me butting in, but I'll take a stab at it. This'll partly repeat what's already been said by others, so please don't take offense.

Ad. 1+2) The noise any object makes is composed of several noises with their own frequency. Think of it as an orchestra, where the sound is made by a set of instruments all playing their own part and together making a sound that you recognize as Mahlers 9th (frequency BTW means how many oscillations per second a soundwave makes. Lower frequencies are low-pitch noises, higher ferquencies are higher-pitched noises)

In the BroadBand display all frequencies are listened to at once and the direction from which a noise is heard is displayed as the trace.

In NarrowBand, the noise is broken down into the frequencies that make up the noise (like unmixing a music tape and seperating the different instruments onto different tape tracks). Those frequencies are then displayed as separate lines in the NB display. The pattern of frequency-lines in the NB display is called the signature.

Every entity has it's own NB signature. You don't have to memorize them, their stored in the ships filter, which you can find in the NB screen. Match up the signature with a signature from the database and you have an identification.

In theory.

In practice, you will more often then not only see the first couple of lines of the signature. Lower freqs travel farther through water then do higher pitched noises. Depending on the distance and the noisiness of the contact you'll get one or more signature lines in NB.

Ad.3) The troughs do indeed correspond to the bearings where the ships hull in obscuring the sonar.

In the lower display of the NB, where the noise is displayed, you can recognize a contact as a peak rising above the background noise at a specific bearing (that particular display repeats the broadband signal, but in real time, not in a waterfall manner). Put the cursor over the peak and in the upper display you should see the freq-lines corresponding to the contact.

Ad. 4) Before the torpedo goes active it doesn't know where abouts the target is. You do (or you ought to, anyways). Usually you have a rough indication of the depth of the target (above or below the layer). Set the runout depth of the torpedo accordingly and it'll find the target when it goes active.

Ad.5) The temperature of the water isn't homogeneous. It changes with depth. The layer is a region of water where the watertemperature changes rather abruptly. Since the temperature of the water also determines the speed of sound through the water, such a sudden change of temperature also radically changes the path sound takes. In fact, the layer more often then not acts like a halfmirror radically reducing the volume of sound traveling through it.

So it is possible to hide on the opposite side of the layer to your target. He'll not be able to hear you as clearly. But you won't hear him as clearly either. It's like pilots hiding in a cloud: There's pros and cons in doing that.

For evading torpedos a layer is almost indispensable. But beware: It isn't a silver bullet. Ever since Sub Command Sonalysts have modelled the effects of watertemps a little more sophisticated then in 688i H/K. The effectiveness of the layer is really dependent on the rate of changes of the watertemperature. If the change is not very radical, the layer will let more sound through (in that case the layer is more like a slight haze then an actual cloud).

Ad. the TMA) I'm guessing you're playing with auto-crew for the TMA on? TMA isn't modelled as an automated system in DW. It's more like a bunch of guys drawing bearing lines from your OwnShips position to the contact every couple of minutes. They take their cues from the different sensors, which is represented by different colors of bearing lines. From those they try to figure out where the ship is, and with what speed it is traveling in which direction.

The problem is, though, that more often then not there's more then one solution that fits the data. If you have three bearing lines running almost parallel to each other a solution of 10nm/7knots is just as valid a solution as 15nm/10knots.

The trick is to manouvre your boat to obtain as much different data points as possible. This reduces the number of solutions untill ideally you have just one solution left. For instance: If you find your target is running roughly parallel to you (lead), try to make two tacks of a couple of minutes: One on a course corresponding to the last noted bearing line and one 30-45 degrees in an opposite direction of where the target is travelling. The information your TMA guys get from those is usually sufficient to workout the position, speed and course of the target accurately.

Ad. DEMON) The Demon 'demodulates' the noise the screw of a target ship makes. It's broken down into a lines for the rotating shaft and a number of lines corresponding to the blades of a screw. So having 6 lines in the DEMON means you're tracking a ship with a 5-bladed screw (that is also a piece of info you can use for identification purposes).

To work out the speed, you have to first have a rough identification. Then enter the TPK (= turns per knot) corresponding to the targets class (you can find this in the USNI database). Then you can put the cursor on the left most line (the shaft line) in the DEMON display and read off the speed of the target.

The accuracy of this obviously depends on the accuracy of your classification. But determining the speed of the target using the DEMON radically reduces the number of possible solutions, earning you the gratitude of your sweaty, stressed out TMA guys.

There's some excellent guides (both TopTorps TMA guide as TimmyG00s Tactical Manual) that I'd suggest you download and read. They explain all this a lot better then I ever could. You can find them over at Bills SubGuru site in the downloads section.

Layer
 

Yet once I feel important to say that in DW, layer effects are quite weak. There has to be very specific conditions to see any effect at all. To 'loose contact' due to depth change is possible only on the border of detection range. You definitelly won't evade torpedo because of the layer. Being on the other side of the layer can delay detection and classification a bit, but again, it takes place only at the detection range border. When they shoot at you, you are much closer and layer can be ignored.

In DW much more important factor is surface noise. It masks contacts. For beter sonar reception go as deep as possible, especially with high seas. In most conditions deep sonobuoys gives better results than shallow ones. I think this is because of surface noise.

This is how it works in DW. I don't know how it works in real.

So, as was said, the layer effect is very small in DW, so the depth where we fire the torpedo has almost no effect on its ability to detect the target. And how does it know the depth of the target? Well... it just does know it :) Its sonar has ability to detect target bearing both horizontally and vertically, i suppose :)

In all honesty, I know absolutely nothing about operating the layer instrument. I read somewhere about this tactic, so I just asked the question.

But about torpedo, I am still very unsure about it. What is the difference between firing it SNAPSHOT and assigning a contact to it? I find there is no difference. By the way, do you steer the torpedo? For once, one of the torpedoes missed the target by over 2,000 yards. I changed the bearing to steer it back towards the target and it hit the hull. But naturally, how does the torpedo know if it should dive deeper towards the target or surf upwards? Does it have a homing radar onboard?

Oh...yes, please also tell me how do I put another torpedo into an empty tube? I have torpedo stocked, but can't use them!?