classification of contacts

[Nexus7]

I think everybody knows how problematic it is to classify each contact in a set of contacts on the same bearing (i.e. Task Forces).
The frequencies can overlap making identification a difficult task...

So why shouldn't the computery deliver us each set of frequencies with a different colour? (i.e. green blue red...)

Wouldn't that be very helpful?

just an idea...

[Bellman]

But its the Nav map where I would like to see SCS giving us some extra tools in the form of drawing aids
and/or symbols.We have limited possibilities to mark up Nav - . But its fiddly and time wasting. Just a palette
of other assignable icons or symbols for the gamer to select for Nav and allocate to taste.

As the Nav is inadequate, I now have made my own interphase between sonar and Nav.

Dang - it having a bad day for wandering off topic !! :damn:
Sorry guys. :yep:
Your chatting away merrily about football and this guy pipes up - ''Saw a Type 20 loco on moday at...........'' yap, yap.

[sonar732]

From my response in patch sugestion...

Nexus7,

Back in 1995, the FRAZ display looked and felt like the current NB of DW for 688's and Seawolves of course.

Question #1: The FRAZ operator would communicate with the SA or TA operators as to what he's seeing and if his guys to the right (how it was set up on my boat, Alaska 732). The only other way we knew what it was is a big red book marked "Top Secret" which showed NB frequencies for every boat and ship class in the world. By the way...I do play with headsets while in SA or TA BB.

Question #2: The FRAZ display doesn't give you two different colors for easier classification.

[Nexus7]

Sonar732,

the bit i know about BB and NB sonar in DW doesn't include "sound" as a source of information, except if the ctc is a loud surface, a torpedo or a CM, and from your answer this seems to mirror the reality :(

As a matter of a fact by overlapping contacts that send more than 1 frequency each, the computer knows what frequencies belong to the same contact.

I know that NB is not primarily used to assign trackers, but you can, and if you try to assign tracker to the second frequency of a contact when you already marked his first frequency, nothing happens, and i think that's because the computer knows that this contact already has a tracker...

Consequently it should be easy and IMO welcome to filtrate the frequencies on NB (in case of overlapping contacts) to yeld the clean set of frequencies of a single contact (i.e. scroll down menue with contacts to chose).

I think even in RL the phenomena of overlapping frequencies can appear, and since things aboard a sub have to be quick & exact I don't understand why such a tool shouldn't be there to be used...

[Bellman]

:) Sonar732 you say you play with headsets, so do I, so can I ask you
to what extent DW mirrors the real BB sounds ?

In-game can the player go beyond getting broad classifications of type, can he be more specific in identification ?
Is it something worth learning and practising when NB is pretty fruitful ?

I must admit to not paying enough attention to this aspect. though. :hmm:

Also with the Demon in-game while I am roughly familiar with blade counts and what the sub return
looks like - would it repay the gamer to be able to recognise and make broad classifications ?

Sorry Nexus7 we posted at the same time and I am still wandering off your topic. :roll: :oops: :damn: :

[sonar732]

All that I will say is that my observations are based from 1995 technology. What has been completed in the 11 years, who knows, but that is how we did it back then.

If you have a strong NB signal with different frequencies then the weak NB signal of a different platform, the computer will always go for the strong one. In RL, that is why we had the "Top Secret" red book...we had to do it ourselves...look up what the "rouge" frequency was of the weak signal because more than likely, it was a threat.

All of these people that complain about a traffic heavy BB or NB need to stop complaining because that is what it was like in RL...trackers moving from one line to another because they overlapped. I can remember getting yelled at by the instructor during our training because I wasn't paying close enough attention to the combined track of two contacts. They were so close that I couldn't tell which was which and had to basically sit on them until they moved farther apart.

Bellman, for the most part, the sounds are "close" to what it is in RL. Granted, I miss being able to hear the hull popping of a submarine or the actual cavitation being produced. Shoot...I still tap my fingers trying to get a turn count. :rotfl:

When you say "can he be more specific in identification?", I admit that I'm a little confused. In RL, we could tell if something had a "quirk" that seperated it from the class of boat/ship...bad shaft seals, messed up propellor, etc.

[sonar732]

I know that NB is not primarily used to assign trackers, but you can, and if you try to assign tracker to the second frequency of a contact when you already marked his first frequency, nothing happens, and i think that's because the computer knows that this contact already has a tracker.

Why would you want to assign more than one tracker on the same contact from the same detection mode? I can understand if you found him in the SA NB and assign a tracker there and then assign a TA NB tracker to a different frequency, but as I asked, why the same detection mode?

[Nexus7]

Sonar732,

I feared I wouldnt be able to explain and that's what happened :oops:


Why would you want to assign more than one tracker on the same contact from the same detection mode? I can understand if you found him in the SA NB and assign a tracker there and then assign a TA NB tracker to a different frequency, but as I asked, why the same detection mode?


I don't want to do that and I'm happy it doesn't work.

The fact that it doesn't, means to me that the computer (or whatever else) knows what frequency belongs to what contact, thus allowing (theorically) to ask the computer something like "show me only the frequencies of contact S01".

Not easy but should be possible :hmm:

[sonar732]

In a word....Nope.

[Fish]

Interesting narrowband display on this side.
Perhaps Sonar can tell us what it is?

http://www.nrotc.umn.edu/wolfpack/sub_club/tacticppt/sonartactics.ppt

[Nexus7]

What is that frame named filter? :ping:

[compressioncut]

Interesting narrowband display on this side.
Perhaps Sonar can tell us what it is?

http://www.nrotc.umn.edu/wolfpack/sub_club/tacticppt/sonartactics.ppt

Which one, the COTS display on slide 21? It looks like a post-analysis program, not something you'd see on a tactical display. The peaks show the intensity of the frequency. It's like the program the guys who we send our tapes to use, but not used on the ship.

[sonar732]

I would've needed a sock if my FRAZ looked like that! :rotfl:

Like I said, without keeping up to date on the current technology, I don't know what the Virginia, Seawolf, 688's, or Ohios use now. Please keep in mind that I used the ancient Q-6 sonar system.

[Dr.Sid]

It can't be different colours, just because the sonar computer does not know that these are 2 contacts. NB even does not know that different freuquencies are part of the same contact (while DW always knows which lines are of the same contact).
All I would like is that filtered singatures would include all signatures which could match. Now when actual signature has more lines then library singature, the library signature is rejected. Which happens when you have 2 contacts on same bearing.
So if library signature has 4 lines and all are available on actual NB bearing, even if there are 4 or 20 more, the signature should be available for clasification (it is not now).

[MaHuJa]

One thing we do not have to fight in DW, is the sound bending across bearings, depending on frequency. IOW, if you cannot assign a tracker to S1:60 and another to S1:125, that is an artificial limitation.


When I come across such, I usually do not spend too much time trying to get sonar classifications - just sending torpedoes into the formation usually wreaks havoc anyway. (I usually try to determine that they are the hostiles I'm hunting for, but that's usually not that hard.)

Occasionally I've sunk more ships than I've spent torpedoes. :huh:

[sonar732]

I'll state again...

In RL, that is why we had the "Top Secret" red book...we had to do it ourselves...look up what the "rouge" frequency was of the weak signal because more than likely, it was a threat.

All of these people that complain about a traffic heavy BB or NB need to stop complaining because that is what it was like in RL.

:hulk: :arrgh!: :damn: :roll:

[Nexus7]

Good point Dr.Sid

But I am surprised that where information is so vital, and being the SA an array of sensors, we can't get frequencies delivered in packets :shifty:

In Fish's file what does the beamforming processor actually do?

[EDIT] Sonar, computers have made big steps forward in the last 15 years, sorry for the insistance but seems hard to believe that signal elaboration still relies to a human :roll:

[SeaQueen]

But its the Nav map where I would like to see SCS giving us some extra tools in the form of drawing aids
and/or symbols.We have limited possibilities to mark up Nav - . But its fiddly and time wasting. Just a palette
of other assignable icons or symbols for the gamer to select for Nav and allocate to taste.

I would love just to be able to draw a box, or a line in the Nav map. Circles are good, but the world has more geometry than that. :-)

[Dr.Sid]

Beamforging: lets talk about towed array. It's the simplest situation.

You have for example 10 hydrophones. Each reads sound from all directions. One hydrophone does not provide any direction information.
There are no physical 'beams'.

But if the sound comes for example from the bearing 45 degrees of the array axis from behind, there will be time shift in signals of each hydrophone. First the sound will be detected by the last hydrophone, then then next (by a split of the second) and next and so on. If the array is stright and the hydrophones are eqally spaced, the time shift between them will be the same.

Only if the contact is about 90 degrees to array axxis, the time shift between hydrophones will be near zero (let's ignore the fact the sound wave is spherical, it has little effect for distant contacts).

The time shift between signal of different hydrophones is proportional to cosinus of the angle between array axis and contact (sound source).

Now you want to detect the time shift for each contact. Here come the 'forged beams'. It works in opposite manner. You don't detect time shift (hence bearing) of contacts. Instead you check for contacts at given bearing (hence time shift) - or on so called beam.

I guess the beamforging procedure is quite complicated and secret, but the basics are clear (I programmed it just for fun). Let's say you want to filter out signals comming from 45 degree beam. You get all hydrophone signals and you do inverted time shift (cos(45) * array size / speed of sound in the water). Then you simply sum the signals. All signals with correct time shift will get stronger (because they will match each eachother - they will be amplified by count of the hydrophones), while other signals will get weaker (or will not get stronger).

More hydrophones you have, better bearing resolution you get.

Even with sphere array you have to forge beams, even if hydrophones has some directional characteristics (hydrophones on the left side hardly picks signals from the right side). But you want to have resolution to degrees and even better. Only beamforging (time shift detection) can do this.

Beamforging is also used for creating directional sound wave for active sonar (or radar). It works in the same way, you just generate time shifted signals for array of transducers.

Hope it was clear enough, sorry, english is not my native language.

[compressioncut]

Now, systems are capable of using color in narrowband contacts using similar principles to what you describe. The narroband information is color keyed to the bearing of the contact, thusly -

http://www.members.shaw.ca/aswmoses/jez.jpg

The changing color follows the changing bearing, so different contacts on different bearings would have different color patterns. We have the system on our hull mount sonar but not the TA (yet), and I'd be really surprised if Americans have it on their surface ship sonars. Possibly in COTS modified LAs and Seawolfs, but I really don't know.

[Nexus7]

Very clear Dr.Sid, thanks a lot :up:

[sonar732]

As I stated earlier in the topic...

Please keep in mind that I used the ancient Q-6 sonar system...and...All that I will say is that my observations are based from 1995 technology.

I guess that I'm still old school in identification. We didn't even have a "filter"...hence why we had the big red book.

[Nexus7]

Sonar732,

as for today i started making use of the headset while hunting. Ahhhh much better feeling to the simulator, for a moment i tought i heard some frigates my 045, a group of taiwanese frigates and an OHP.

Much better feeling with headset :up:

[Nexus7]

First of all I want to say :up: :up: :up: to SCS programmers team. Having played a lot of different games so far i find DW to be one of the less bugged but most challenging :rock:




Now back to topic:

I am playing Russian Rebelliol Campaign, 5th or 6th mission where you are at a latter time tasked to sink Rebel, Taiwanese and USA forces (diving the Akula I). Chinese joined my party so i both have enemy and allied. Now I found first the Oscar II and the VIctor III then the Taiwanese Frigate Knox and the OHP north east, along with a third Taiwanese frigate.
While I was able to classify those frigates with a good confidence I was able to engage them right away.
All another matter with the Victor and the Oscar :(
I decided to observe theyr attitude to decide if friendly or hostile. Game went some hours, those Russian subs were all the time very close to me without engaging me, making me consider them friendly after some hours (I could see the Victor III in HF sonar :o ).
Since I accomplished partial objective (sink enemy frigates) I went active to accomplish objective 2 (sink enemy subs). Even then the Victor didnt engage me and I was sure he was friendly. All i found with active was the Victor and my allied Akula.

I hate to cheat when I want to understand :-j but being a little drunk I turned "show truth" ON, watching the replay.
WIth some disgust i found the "HF friend" Victor to be the enemy :damn: :damn: :nope:

Now, how I wish I could I have known that my last enemy was my HF friend :cry:

[sonar732]

Sonar732,

as for today i started making use of the headset while hunting. Ahhhh much better feeling to the simulator, for a moment i tought i heard some frigates my 045, a group of taiwanese frigates and an OHP.

Much better feeling with headset :up:

It does add to the "feel"! Have one on your ear, and the other behind or in front of it. We did this so we could hear what the other crewmembers were saying while focusing on the job at hand. :up:

[bubblehd647]

It does add to the "feel"! Have one on your ear, and the other behind or in front of it. We did this so we could hear what the other crewmembers were saying while focusing on the job at hand. :up:

Need to hear when a coffee order is being taken. :up:

[Bellman]

Fish - nice link to 'The Wolf Pack' Thanks. :|\ :ping:

I will take the printout to read on patrol in 'The Kara Sea.' :yep: :rock: ;)

[sonar732]

It does add to the "feel"! Have one on your ear, and the other behind or in front of it. We did this so we could hear what the other crewmembers were saying while focusing on the job at hand. :up:

Need to hear when a coffee order is being taken. :up:

All that I will say is that I honed my coffee making skills and what a package of hot chocolate does for a bad cup of coffee during a slow watch. :rotfl: :rotfl:

[Nexus7]

So I think a "quantic jump" in the discussion is in order :lol:

Within the older history of subwarfare and my primitive knowledge in the matter, the reported use of force (launch of torpedoes) limits to the Falklands war.

I, as totally not competent in the matter, have to guess: what is the objective of actual submaritime deployment? The reality is that there's always a good number of submarines underway. As ignorant; what could the reason be?

While in DW a fight is a must, what does a normal "leave docks" feel like? :D

[TLAM Strike]

Within the older history of subwarfare and my primitive knowledge in the matter, the reported use of force (launch of torpedoes) limits to the Falklands war. To my knowledge these wars involved submarines in combat (shooting or shot at) roles:
US Revolution (1 unsuccessful attack)
US Civil War
WWI
WWII
*Korean War (Supposedly 1 Russian submarine sunk by US)
*Cold War (Supposedly incidents of Russian subs firing on US Subs)
Six Day War (1 unsuccessful attack)
*Indo-Pakistani War of 1965 (Supposed attacks by Pakistani Submarines)
Indo-Pakistani War of 1971 (INS Kuhkri sunk by submarine PNS Hangor, PNS Ghazi sunk by INS Rajput or weapons casualty)
Falklands War
Gulf War (Tomahawks)
Balklands War (Tomahawks)
Kosavo War (Tomahawks)
Afghanistan (Tomahawks)
Gulf War II (Tomahawks)

*Never positively confirmed to my knowledge or possible non-hostile acts (Cold War exercise incidents)

[Kapitan]

there have been times when US subs have been to close to russian exercises and the Russians sort of well erm fired, in blind mans bluff Dan Rogers recalls such an incident.

how ever no USA submarine has ever sunk a russian submarine unless of course K219 and K278 oh and K141 were asll sunk by magical MK48's (and other torps's)

the notion that america would dare fire on a russian (and vise versa) would be utterly stupid beyond belief, but in saying that if bush jr was in power somthing id expect him to do :hmm:

[Nexus7]

Within the older history of subwarfare and my primitive knowledge in the matter, the reported use of force (launch of torpedoes) limits to the Falklands war. To my knowledge these wars involved submarines in combat (shooting or shot at) roles:
US Revolution (1 unsuccessful attack)
US Civil War
WWI
WWII
*Korean War (Supposedly 1 Russian submarine sunk by US)
*Cold War (Supposedly incidents of Russian subs firing on US Subs)
Six Day War (1 unsuccessful attack)
*Indo-Pakistani War of 1965 (Supposed attacks by Pakistani Submarines)
Indo-Pakistani War of 1971 (INS Kuhkri sunk by submarine PNS Hangor, PNS Ghazi sunk by INS Rajput or weapons casualty)
Falklands War
Gulf War (Tomahawks)
Balklands War (Tomahawks)
Kosavo War (Tomahawks)
Afghanistan (Tomahawks)
Gulf War II (Tomahawks)

*Never positively confirmed to my knowledge or possible non-hostile acts (Cold War exercise incidents)

Well I meant the use of torpedoes only, and after WWII... but interesting list anyway :up:

[TLAM Strike]

Well I might move the Korean war one to Confermed status. And the Russian sub might have even shot back.

http://members.tripod.com/~breastroker/mckeansubhistory.htm

[Kapitan]

A russian built sub maybe but not one crewd by russians thats what i believe simply because any right minded soviet skipper would have fired a nuclear torpedo, also the north koreans do have russian built subs in thier navy.

Also dont you think the russians would have sent out the entire pacific fleet to hunt down the b***stead that did it? not to mention the implications of sinking a nutrel submarine (russia not formaly part of the war).

the back lash would have ment me and you wouldnt be sitting here tapping keys

[TopTorp '92]

I think everybody knows how problematic it is to classify each contact in a set of contacts on the same bearing (i.e. Task Forces).
The frequencies can overlap making identification a difficult task...

So why shouldn't the computery deliver us each set of frequencies with a different colour? (i.e. green blue red...)

Wouldn't that be very helpful?

just an idea...

There is a tactical argument to be made here.

First, if you are in a situation where the frequencies overlap, then that means there are two or more contacts down the bearing to your target of interest. You must drive for bearing separation in order to split the bearing to the frequencies and to better classify your target as well as get a range.

Also, knowledge of the basic line-of-sight diagrams will help you decide how to best drive for extra bearing rate. Bill has posted my TMA papers on his website where I have outlined most of the relevant LOS diagrams. What's better in my opinion is that once you know LOS you don't need that silly NAV plot that is too cumbersom to utilize anyway. With this knowledge you only need to focus on the relevant information.

Second, instead of driving for bearing separation using the first method, you can always deploy your towed array (assuming you have one) and observe the differences in bearing between the two or more targets. Further, you will be able to see whether any of the possible targets appear both on the towed array as well as on the spherical array.

I have noticed that Dangerous Waters does an excellent job at modelling these kinds of variables in the Target Motion Analysis (TMA) arena. Since you pay only a small premium to use the DW software, I think you're getting good insights about TMA problems.

Third, if you are unable to get a good tactical picture using sonar, then your final opportunity will be to use the periscope and ESM mast.

Finally, whichever combination of methods you use, you will have made better ranging estimates of either target and you probably will have made a better tactical picture of your target environment. With this information you will be able to move into more agressive modes of tactical operation and improve the probability of a successful attack.

Good hunting
Top Torp

[TLAM Strike]

A russian built sub maybe but not one crewd by russians thats what i believe simply because any right minded soviet skipper would have fired a nuclear torpedo, also the north koreans do have russian built subs in thier navy.

Also dont you think the russians would have sent out the entire pacific fleet to hunt down the b***stead that did it? not to mention the implications of sinking a nutrel submarine (russia not formaly part of the war).

the back lash would have ment me and you wouldnt be sitting here tapping keys Can't fire what they don't have Kap. The 53-58 was the 1st Sov Nuc fish and it was built in 68. Remember that the Korean War happened in 1950-1953, at this time Russia just finished its 1st A-Bomb ('49) and was experimenting with H-Bombs. I don't believe there were even nucs sufficiently small to fit on a torpedo at this time.

Also remember that at this time the Russians didn't have a very large navy. They had a few battleships, a few cruisers a assortment of DDs and smaller ships while the UN forces had probably one of the largest navy's ever built at its disposal- remember this was right after WWII when the US navy had dozens of carriers sitting around.

Besides the Russians had no problem secretly sending MiG pilots to fight for the north, why not a sub?

Plus my Grandad manned the DEW Line in northern Canada so I might be here if worse came to worse.

[Dr.Sid]

My only problem with contacts on same bearing is these:
1) autocrew won't clasiffy them.
2) Filter does not work properly (usually will show no available signature), so it is really hard to me to classify them by myself. I have to scroll thru all available signatures.

Very often these are questions of live and death. Is there a sub behing that group ? Those 2 cons near each other .. are those fishing boats or Akulas ?

I usually know aht I'm looking for. It is just pain to find out.

[Wim Libaers]

My only problem with contacts on same bearing is these:
1) autocrew won't clasiffy them.
2) Filter does not work properly (usually will show no available signature), so it is really hard to me to classify them by myself. I have to scroll thru all available signatures.

Very often these are questions of live and death. Is there a sub behing that group ? Those 2 cons near each other .. are those fishing boats or Akulas ?

I usually know aht I'm looking for. It is just pain to find out.

DW_SonarProfiles.doc. A file that, IIRC, was added by one of the patches, in the manual subdirectory of the directory where DW is installed.

[compressioncut]

My only problem with contacts on same bearing is these:
1) autocrew won't clasiffy them.
2) Filter does not work properly (usually will show no available signature), so it is really hard to me to classify them by myself. I have to scroll thru all available signatures.

Very often these are questions of live and death. Is there a sub behing that group ? Those 2 cons near each other .. are those fishing boats or Akulas ?

I usually know aht I'm looking for. It is just pain to find out.

DW_SonarProfiles.doc. A file that, IIRC, was added by one of the patches, in the manual subdirectory of the directory where DW is installed.

It doesn't matter - very often, the first three emitted frequencies of very different targets will be exactly the same. And because the proploss of higher frequencies is higher, you will much, much more often than not, not get that distinguishing fourth line at any sort of tactically useful range.

If the displays in the game showed us the Doppler effects (that are present) on the lines in a useful manner, differentiating contacts on similar bearings would become much easier. As it is, the integration periods are much too fast to show Doppler usefully. The narrowband integration periods, especially on the sonobuoy processor, need to be similar to the broadband ones, and we need the frequencies to read to two decimal places. This is becoming an increasingly frustrating issue for me, because the capability is there, and would add so much more to the game.

[Dr.Sid]

I don't see ANY dopler effect enywhere. For circling torpedoes it should be clearly visible independently on any 'integration period' whatever it may be.

[Bellman]

Never seen this before - diving SeaQueens Kara Sea scenario.

I was holding a contact, supected Akula, had her at 33 nm on BB and refining TMA. Had previously tacked
to no effect in improving matters.

Then as I tacked again watching in NB as the TA was straightening out, I got the first four freqs. -
enough to distinguish the Aks 1100 from the Typhoons 1000. As quickly as the tonals appeared, they faded away,
as the TA became straight. I could not repeat this !

This should'nt have happened ! :hmm:

[sonar732]

Never seen this before - diving SeaQueens Kara Sea scenario.

I was holding a contact, supected Akula, had her at 33 nm on BB and refining TMA. Had previously tacked
to no effect in improving matters.

Then as I tacked again watching in NB as the TA was straightening out, I got the first four freqs. -
enough to distinguish the Aks 1100 from the Typhoons 1000. As quickly as the tonals appeared, they faded away,
as the TA became straight. I could not repeat this !

This should'nt have happened ! :hmm:

The towed array could've slipped below the layer with you right above it. :hmm: :ping:

[Kapitan]

TLAM sorry was thinking of something else, at the time you state russia was building up its fleet, so it would have had about 50 submarines most of which being whiskey and qubec class (early whiskeys went into numbers of 250 and two are still active).

as for the qubec they were an elaboration of tthe german type 21 in other words they were propelled by HTP just almost like the ones of today, (later changed to conventional).

As for sinking a russian sub still got the backlash of the political state

[Bellman]

:) Thanks sonar 732, but that was not so in this case :

My SW depth 139 feet. Speed 5 knots.
Layer - 666 ft. SSP Isovelocity - split beam pattern.
Target - 328 ft.** At range 33 nm !!
** In order not to spoil the ongoing scenario I zoomed into my TMA solution,which was accurate,
before turning Truth on.

All I can think is that I hit a surface duct or got a lucky bounce ? :hmm:

[TLAM Strike]

TLAM sorry was thinking of something else, at the time you state russia was building up its fleet, so it would have had about 50 submarines most of which being whiskey and qubec class (early whiskeys went into numbers of 250 and two are still active).

as for the qubec they were an elaboration of tthe german type 21 in other words they were propelled by HTP just almost like the ones of today, (later changed to conventional).

As for sinking a russian sub still got the backlash of the political state Don't forget the small force of M-V, S (Stalinets and Shchukas), and K (Katyusha) class subs leftover from WWII. And the Zulus.

Also I don't think there would be much political backlash, if the Russians were sending them in to a War Zone looking for trouble they would have been willing to accept their loss much like the previously mentioned MiGs that supported the North Koreans/PRC. They probably would have just accepted the US cover story and never brought up the topic, I doubt the Russians would have wanted the UN forces to Nuke the Koreans and start marching right in to Russia- the Russians should know how much a two front war sucks!

[Kapitan]

i see your point but how come its not declassified after what 50 years?

[TLAM Strike]

i see your point but how come its not declassified after what 50 years? I don't think anyone wants to drag this up officially considering the state of affairs in that area of the world right now but two of the AARs from that incident have been declassified. Check the link I posted. I doubt the Russians would let any of their documents out since it would make them look bad (escalting a war, losing a submarine take your pick).

[Kapitan]

Personaly i think both sides were right one defending capitalism one communism ie both supporting potential allies.

Think it should have been kept a seacret russians are very patriotic (the elder hardend communist ones) would have wanted blood or a war with america if they heard about it.

So maybe scorpion was lost to a russian torpedo hmmm who knows..........after all it did moniter a russian fleet movement of extreme importance

[SeaQueen]

All I can think is that I hit a surface duct or got a lucky bounce ? :hmm:

My suspicion is that you might have gotten some kind of multipath interference effect, yeah. I don't know how much detail the DW sonar model goes into regarding that, though.

It's interesting that in the Seawolf you get so much larger ranges.

[compressioncut]

I don't see ANY dopler effect enywhere. For circling torpedoes it should be clearly visible independently on any 'integration period' whatever it may be.

It's plainly visible especially on circling torpedoes. I posted at least one thread in this forum when the game was released with screenshots. When you drop a torp on a crossfixed target you can see up, down, and multiple CPA occurences, even with the half second or whatever integration the buoys run. I'll check my Imageshack directory to see if they're still there, but it's very easy to confirm.

It's also quite noticeable on narrowband towed array contacts, although due to the low frequency detections (usually 50 or 60 Hz depending) it's a pretty small effect, and not useful due to single decimal place accuracy, and short integrations. Also, the way the frigate TA's single beam window does not display historical acoustic information makes it fairly useless tactically (although its integration is quite long - just can't win).

Never seen this before - diving SeaQueens Kara Sea scenario.

I was holding a contact, supected Akula, had her at 33 nm on BB and refining TMA. Had previously tacked
to no effect in improving matters.

Then as I tacked again watching in NB as the TA was straightening out, I got the first four freqs. -
enough to distinguish the Aks 1100 from the Typhoons 1000. As quickly as the tonals appeared, they faded away,
as the TA became straight. I could not repeat this !

This should'nt have happened !

Rule of thumb - if you are holding a contact at extreme range it's a CZ contact. If you get all four tonals at 33 miles it is 99% a CZ contact because that is the very nature of a CZ contact - there is very little proploss over the CZ which makes it the preferred detection path, among other reasons - in the caustic, the sound is actually focused, so the source level could very well be higher than a direct path.

And then they faded out? Well, either he or you was on the outside of the CZ.

What a lot of people seem to misunderstand about CZ is that the sound is focused at the sea surface - that is not correct at all. It depends on the source depth, and there can be multiple focusings of the sound throughout the water column depending on conditions. The depth of the source also has a great effect on the depth excess required for 50% and 80% probabilities of CZ - the depth of the sub in the same SVP can make it go from one to the other.

I did a fair amount of testing of CZs in Dangerous Waters and it seems to work pretty well.

That said, I don't know how a sub would carry out a CZ engagement without some sort of SUBROC weapons system. That's why towed array surface vessels have helicopters!

[Bellman]

Thanks compressioncut.

In setting up the Kara Boomer attack, it certainly helps to distinguish the Akula outrider !
But the CZ could be a two-way street.

Not sure what affect the numerous Kara icebergs have on the near surface CZ- is it modeled in-game I wonder ?

Kara with its bergs, constantly varying layers and shallows is tricky but add in sonar receptivity which
varies from end of your nose to telescopic sight ranges and it becomes a nightmare...............
Just a perfect place for Boomers to lurk.

[SeaQueen]

Thanks compressioncut.

In setting up the Kara Boomer attack, it certainly helps to distinguish the Akula outrider !
But the CZ could be a two-way street.

Not sure what affect the numerous Kara icebergs have on the near surface CZ- is it modeled in-game I wonder ?


The water in the Kara Sea is too shallow for there to be a CZ proper. What you're seeing is some other type of multipath interference effect, where certain rays of sound are refracted upwards towards the surface and bounce off the undersurface of the ice, then head back downward again. Other rays bounce off the bottom. These two groups of rays interfere constructively and destructively with each other, creating all kinds of weird things.

Detection isn't necessarily a two way street, though. That would be assuming the ocean is homogenous in all directions and it's not. It also depends on things like operator skill, and the equipment's quality.


Kara with its bergs, constantly varying layers and shallows is tricky but add in sonar receptivity which
varies from end of your nose to telescopic sight ranges and it becomes a nightmare...............
Just a perfect place for Boomers to lurk.

Yeah... in real life, the arctic doesn't generally have a layer. It's just uniformly really really cold, all the way to the bottom. I chose the surface duct environment, because it seemed to have the strongest positive gradient, but unfortunately, that introduces a falsehood. There is no thermocline in the arctic, so there is no sonic layer.

The other option was the "bottom limited" SSP which shouldn't have a positive gradient at all, but that's a whole other lecture. :-)

But yeah, the Kara Sea and Barents Sea, as well as the Sea of Okhotsk were the big places where Soviet (and Russian?) boomers hid, percisely because their acoustic environments were very difficult and the ice hid them from maritime patrol aircraft and space-based sensors.

[Kapitan]

Still do

[compressioncut]

The other option was the "bottom limited" SSP which shouldn't have a positive gradient at all, but that's a whole other lecture. :-)


Ummm, there is still a pressure increase with depth which increases sound velocity, even if the temperature curve is isothermal or slightly negative.

I didn't catch the bottom depth in the scenario Bellman described and was just going on sonic layer depth. But it still sounds exactly like a CZ nevertheless. Bottom bounce causes scattering and is affected by absorbtion losses, especially at high frequencies (the 1100Hz line would not have made it), and a 33 mile bottom bounce is pretty incredible anyway.

I suppose it could be something as simple as a duct.

[Bellman]

compressioncut - The first instance I was relatively blind with a bottom depth of 745 ft and layer at 603 ft and Isovelocity.
The interference in sonar indicated strong currents and although I changed depths I ran at relatively deep depths.

The long-range receptivity, mentioned above, was with a bottom at 698 ft and an SSP with a very slight positive gradient
- no layer shown. I ran between 140- 120 ft. depths.

[SeaQueen]

Ummm, there is still a pressure increase with depth which increases sound velocity, even if the temperature curve is isothermal or slightly negative.

That's true. But in general, except in very shallow waters, "bottom limited" means that the sound speed at the sea surface exceeds that of the speed at the bottom. That is to say, there's a negative gradient to the SSP. That's why the sound is refracted into the bottom. So what you end up having is an SSP that looks very much like a CZ SSP in terms of it's hooked shape, but the sound's speed at the surface is very high. Bottom limited environement are typical of places near the tropics, where the water is usually very warm near the surface.

But it still sounds exactly like a CZ nevertheless.
And it should! Ultimately, what it boils down to, is that there's a spot, someplace in the ocean, where the transmission loss for the rays connecting the target to the searcher is low, for whatever reason.

Bottom bounce causes scattering and is affected by absorbtion losses, especially at high frequencies (the 1100Hz line would not have made it), and a 33 mile bottom bounce is pretty incredible anyway.


True.

I suppose it could be something as simple as a duct.

That's what I was saying. Even within duct there is constructive and destructive interference, due to multipath effects. That can cause signals to fade in and out in very interesting ways. Even for very short ranges this can happen due to things like the Lloyde Mirror effect, although I don't think that's modelled in DW (maybe it is? it's not hard... huuum)