Detection Range Glitch?????

[swimsalot]

Ok, need some professional adice on detection ranges.
Recently have noticed that a player consistantly seemed to be able to acquire other players very quickly, at long ranges.
Unnamed player would be in an Akula, others in SW.
Having heard about this happening to other players, I was curious as to how it was happening. Not worried about a cheat, I was worried about my own skills.

At 15-20 minutes into the game, Akula would fire missile torps at Sw, landing them within 700yards of where the SW started mission.
Sw usually wasnt there anymore, but pretty close- close enough to kill the SW 4 out of 5 times. Not bad.

Since I was bored, and a little suspicious, I replayed the map.
It's a busy map, 3 cargo/car carriers in the area, 20nm circle. A few trawlers outside the circle.
1 Akula and 1 SW inside.
Akula was 19.1nm from SW, both at about 190 feet, both speed 6kts.
Layer at approx 370 feet.
SSP was rock bottom, SD.
Sea state was light chop, daytime.
The Akula apparently picked up the SW at 19,1nm, and at 14minutes fired a salvo of missile torps at him, which he narrowly evaded. taking into account the time needed to stream the array, acquire and mark contacts,preset, and fire, I thought 14minutes was pretty damn fast for 19.1nm range.

I had the mission designer that made the original map set up a new map with 3 subs in it, same size and SSP, no neutrals.

All subs started at 192 feet, 6kts, above layer that was at approx 500feet.
We then spent a few hours checking detection ranges.
We found a curious situation, which bears further review.

At beginning of mission, for the first 4-5 minutes, I was able to hear the SW, which at the time was 48,000 yards away. Clear solid 60hz line.
I could hear the Akula at 38,000 yards, with clear line at 50hz and 125hz.
Seemed a little far away for a good track on a SW.
The Akula tracked both Seawolves at mission start, 1 at 38,000 yards, other at 44,000 yards!!!!!

So all subs were able to hear contacts at 44-48,000 yards at mission start.
Wierd thing is that 5-10 minutes into the mission, the contacts disappeared, or got alot quieter.
But the auto -TMA kept tracking the contacts, updating lines on the TMA chart!!!
I had my Gamma settings tweaked up by Powerstrip, so I can see even the faintest contacts.
We didnt slow down or head away from each other; I closed range on the SW until I re-acquired him at about 38,000 yards.
This would be where I would expect to hear a SW at 9kts.

So why could we ALL hear each other, at these ranges, at mission start, but not 10 minutes into the game, if no changes had occurred to speed or depth?

Is 48,000 yards detection against a SW, by a SW, too far?
Is 44,000 yards detection against a SW by an Akula to far?

I have the map our designer made if you would like to try it out.
Nothing fancy, should be easily reproduced.

I think this unnamed player has figured out that if ya get a contact at the very beginning, auto-TMA will track it even if it's not visible to you.
And initial detection ranges at start are far in excess of what I thought were normal ranges.

1 time random thing? Maybe, except the unnamed player did it a handful of times. And we were able to reproduce it, I ran it 2 times myself.
A glitch in the code?
(we were running plain 1.03, no mod.)

Thoughts?


NOTE- I am specifically NOT accusing anyone of a cheat- I think there is a glitch in here that someone figured out.
(sorry fpr length!!!)

[TLAM Strike]

Sorry to say but we've heard this before:
http://www.subsim.com/phpBB/viewtopic.php?t=51872

[LuftWolf]

Was the SSP by any chance, a convergence zone?

Because that is the behavior you are describing, if we are to assume that the game is functing properly.

[swimsalot]

TLAM: I read that other thread when it came out. It has nothing to do with what we re-created. I don't think this is a cheat, and we made the map, so there is no worry over mission triggers.
We weren't in our baffles, nothing that simple.

As anyone that has played with me would know, I am not inexperienced with this sim. I understand when a sub should be there, and when it shouldn't.

LW:The designer that made the map tried it with a few different variations (ie SD, convergence,etc) all had same result.

Please, could someone with vast experience run the same setup we did and try to duplicate this?

[LuftWolf]

How about posting the setup at the CADC?

[swimsalot]

RGr, will try to post it now

[Fish]

Originally Posted by swimsalot

TLAM: I read that other thread when it came out. It has nothing to do with what we re-created. I don't think this is a cheat, and we made the map, so there is no worry over mission triggers.
We weren't in our baffles, nothing that simple.

As anyone that has played with me would know, I am not inexperienced with this sim. I understand when a sub should be there, and when it shouldn't.

LW:The designer that made the map tried it with a few different variations (ie SD, convergence,etc) all had same result.

Please, could someone with vast experience run the same setup we did and try to duplicate this?

Swims, I like to try that map on my LAN. I think the original map is from Mf?
I was talking with him yesterday about the "glitch" and made a map for LWAMI to do some tests.
I can't get something like wise with the mod, I can see the Akula (while in the Seawolf) at 6 knts 12 nm away, but I can't see the Seawolf (from the Akulas side) other then when the SW is at a speed of 13 knts or more.
Fish.

[Bellman]

Swims: Confirmed your findings with that scenario in Stock. Dived SW which gave immediate TA SNRs of 1 on the other
SW (22nmn) and Ak (21.5 nm) Within 4 minutes faint base tonals allowing trackers to be assigned. ATMA then
switched on and off and with manual assistance by WF the solution on the Ak (No Truth) was 2.8 nm out.
Ak NB+ ATMA proved just as farsighted. In Ak NB I had SW(A) at 20 nm and SW(B) at 21.5 nm. The above was a typical
playing of this scenario and the other reruns followed the same pattern................The ATMA cheats !

I noted on replaying the mission several times that the starting positions were not randomised adequately.
The SWs random boxes are only 1.5 nm square and the Ak has a fixed starting position ! Note also that the Ak
starts with TA deployed but the SWs are not ! As I proved after only half a dozen runs
anyone familiar with this scenario and its 'peculiarities'would have a distinct advantage over opponent/s.
But on the other hand all subs enjoy the same super receptivity so the scenario creator only enjoys normal priviledges.

Another thing briefly - could the topography influence receptivity dramaticaly in this case ? The Aks position is
at the focal point of a sound bell - the shaping and the depth of the seafloor creates a perfect megaphone
and/or receiver shape. It might have a bearing on sonar performance ?:hmm: Perhaps the limited
range of starting positions seeks to maximise this feature ?

I am sure RADM Fish + Lan will provide a more informed second opinion.

[sonar732]

Was the culprit the hoster?

I hosted a mission once on gamespy and an unnamed person sent me a message to SHIFT+CTRL+T (show truth for those who don't use hot keys). I played dumb and asked him why and he didn't reply back.

[compressioncut]

Well, without knowing the bottom depth it's not possible to know for sure if CZ was present, but the ranges sound short for an in-layer contact. They are closer for submerged CZ but the subs were in the layer. As well, in the game you normally have to force a CZ SSP to get CZ above layer.

And assuming that cutoff frequency is modelled, the 50 or 60hz tonal probably should not have been ducted in a 370 foot layer. Depending on the magnitude of the duct. I'm just guessing cutoff would be around 170hz, but again, I don't know the duct's magnitude (velocity at surface versus velocity at sonic layer).

But, a rock bottom and 20 mile ranges sounds very suspiciously like bottom bounce. If a rock bottom in game is modelled as smooth rock then its not completely out of the question, as bottom bounce is a path a lot of people don't account for - there's little absorption or scattering from smooth rock. And it will behave similarly to a CZ, except calculated ranges could be a little out (as you experienced).

Still a little weird for state of the art subs to detect one another 20-25 miles away. I suspect it's something to do with the environmental modelling, in that there is probably not a great deal of ambient noise like there is/can be in the real ocean, especially at very low frequency.

[Bellman]

Well when diving the SSPs Isovelocity over negative - Surface duct and mud bottom ! Layer at 550-600ish ft. variable.
(All subs above !)
With this split-beam pattern I wonder whether the topography could enhance the surface ducts receptivity range ? :hmm:

[swimsalot]

The map I posted at tha CADC is just a test map based on the same sonar conditions in the map I was concerned about; the designer didnt make random start areas, etc for the test map.
The original map was a mp map with same SSP, but with neutrals, bios etc.
Again, all I noticed was that the detection ranges seemes a little long, particularly for the Akula.
And the fact that they faded at about 4-10 minutes every time irregardless of ownship speed or target speed.
Thanks for the info guys, this is a good learning situation either way!

[Mcfester]

Originally Posted by Bellman

I noted on replaying the mission several times that the starting positions were not randomised adequately.
The SWs random boxes are only 1.5 nm square and the Ak has a fixed starting position ! Note also that the Ak
starts with TA deployed but the SWs are not ! As I proved after only half a dozen runs
anyone familiar with this scenario and its 'peculiarities'would have a distinct advantage over opponent/s.
But on the other hand all subs enjoy the same super receptivity so the scenario creator only enjoys normal priviledges.

The map you tested was a test map taken from the original mission map, all neutrals, bios, and dynamic start locations removed and subs placed in same positions as they started in the mission that was played where the problem was first noted.

[OKO]

Originally Posted by Bellman

... I wonder whether the topography could enhance the surface ducts receptivity range ? :hmm:

confirmed, bellman
Bathymetry is a very complicated thing really ...
But there is a very usefull tool to use it : SHIFT + I on the nav screen
With this shortcut, you could switch beetween "depth+SNR", "SNR only" and "nothing"
3 selections.
If you want to find the best place around to listen, use SNR only with SHIFT + I, and use the darkest area next to you : here you will have the best SNR you could find around, so the best listening capabilities.

If one ship is on a very dark area, and the other one is on a bright area, the one on the dark zone could detect first the other, because he is in a more quiet water and could hear at longer range, when the other have his sensor perturbated by a bad SNR.

Topography have great influence on SNR, you could see this because there is only few difference, usually but not always, beetween relief and SNR.
But it could be VERY different on some places.
I had maps where it was completly different, where dark areas were often shallower than bright areas !

One often believe that the darker the area, the deeper the water, but that's not always true, and sometimes completely false ! (see some shallow area around filipines)

So, to avoid any misinterpretation, if you look for the best area to position yourself for detection, use SHIFT + I to find the darkest area near you.
And it's not always the deeper places !

[Bellman]

OKO: Perhaps we should distinguish between the ''complicated'' RL and what is present in DW. (good though it is)
I am very familiar with that ''tool'' ! But your lecture will be appreciated in some quarters !

You should be aware that the copy of the scenario now available at CADC is not the original one. It has been
swapped for one which exhibits none of the characteristics observed by Swims or from my runs !

Edit - See below