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Deathblow
Joined: 11 Sep 2005
Posts: 392
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 Posted: Sun Apr 09, 2006 10:25 am Post subject: Two TA = No bearing ambiguity |
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OkeeDokee....Hypothetically....
If any ship were to deploy two towed arrays at the same time (as in the dual towed array systems being developed by some navies), then hypothetically both towed arrays together would be able to detemine "true bearing" to the contact without having to undergo ship course changes. The signals detected on the TA would just be time compared (to see which TA is seeing the signal a fraction of a second before the other, that TA is toward the real contact and not the mirror).
That being accepted as true.... shouldn't submarines be able to deploy both their TA to eliminate bearing ambiguity?
I have a theory that some subs do this already....... related to a theory that I have that the SW and VA actually have more than 2 TA (perhaps 3 - 4, and that is the reason it has 2 seperate TA fins instead of streaming the TA from the aft control surfaces like previous designs).
Therefore... I vote all US subs TA have their "mirrored contact" stats removed.   |
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TLAM Strike
Joined: 30 Apr 2002
Posts: 4866
Location: Rochester, New York
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| Posted: Sun Apr 09, 2006 10:49 am Post subject: |
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:huh:
With two TAs you would have two ambiguous bearings and two true bearings. :nope:
EDIT: As for testing the time a sound is recived by the TA that might (stress might) work with a contact off its beam but not with a contact fore or aft of it. And it might not work with a contact thats abeam unless it makes a trasient noise. |
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GunnersMate
Joined: 17 Feb 2006
Posts: 225
Location: Boston, MA
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| Posted: Sun Apr 09, 2006 10:58 am Post subject: |
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| And you'd have the task of syncronizing both TA's |
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SeaQueen
Joined: 23 Jun 2005
Posts: 358
Location: Washington, DC
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| Posted: Sun Apr 09, 2006 11:22 am Post subject: Re: Two TA = No bearing ambiguity |
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| Deathblow wrote: | OkeeDokee....Hypothetically....
That being accepted as true.... shouldn't submarines be able to deploy both their TA to eliminate bearing ambiguity? |
You're actually right on. In fact, by measuring the phase differences between corollated signals you could also determine the range. There's also some tricks to it, though.
In order for that phase difference to be measurable, you need to have the two towed arrays sufficiently separated. It's not clear to me that streaming a pair of towed arrays behind an SSN would result in sufficient separation. I suspect some other systems might use the technique. Also, signals become distorted as they travel through the water, so corrolating signals is not necessarily an easy thing to do.
They actually used to do a similar thing to what you're talking about with LOFAR sonobuoys, and use that to determine bearing and range with an omnidirectional sonobuoy. Unfortunately, the model doesn't really take that into account. |
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Deathblow
Joined: 11 Sep 2005
Posts: 392
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| Posted: Sun Apr 09, 2006 11:33 am Post subject: |
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| TLAM Strike wrote: | | EDIT: As for testing the time a sound is recived by the TA that might (stress might) work with a contact off its beam but not with a contact fore or aft of it. And it might not work with a contact thats abeam unless it makes a trasient noise. |
Not neccessarilty. The signal will be continously time shifted with or without a transient. As the sound is continuously intercepted, the signal/sound waves should have a predictable latency real-time, imho. Though how accurately it could be determined I don't know.
http://www.lockheedmartin.com/wms/findPage.do?dsp=fec&ci=17302&rsbci=0&fti=112&ti=0&sc=400
| Quote: | | The SURTASS TL-29A twin-line system is an underwater passive acoustic sensor with a pair of arrays towed side-by-side from a ship. The TL-29A delivers unsurpassed capabilities, such as its ability to be towed in very shallow water environments in the littoral zones, to provide significant directional noise rejection, to resolve bearing ambiguities without turning, and to allow the ship to tow at higher speeds |
http://www.fas.org/irp/program/collect/99-06_t-agos_upgrades.htm
| Quote: | | The twin-line array, which was developed by a joint government-industry team comprised of the John Hopkins University Applied Physics Laboratory, Chesapeake Sciences, and the Navy’s Array Technical Support Center, Little Creek, Va. employs COTS telemetry architecture and consists of two short parallel acoustic arrays separated by several meters. The array provides for left-right ambiguity resolution, back lobe rejection, and the flexibility to tow in shallow water |
So this capability already exist and is probably already deployed in some regards... only question is whether the distance seperating two TA on a submarine is sufficient enought to do the job... :hmm:
Down with bearing ambiguity!! .... at least for US subs
Last edited by Deathblow on Sun Apr 09, 2006 11:50 am; edited 1 time in total |
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Deathblow
Joined: 11 Sep 2005
Posts: 392
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| Posted: Sun Apr 09, 2006 11:49 am Post subject: Re: Two TA = No bearing ambiguity |
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| SeaQueen wrote: | | In order for that phase difference to be measurable, you need to have the two towed arrays sufficiently separated. It's not clear to me that streaming a pair of towed arrays behind an SSN would result in sufficient separation. I suspect some other systems might use the technique. Also, signals become distorted as they travel through the water, so corrolating signals is not necessarily an easy thing to do. |
That is what I was thinking as well. It would probably take a whole lot of processing power to crunch through all the signal distortion, and provide an accurate deduction. Perhaps the COTS programs in the works are addressing the need.... I also wonder if the TAs themselves being a source of drag noise "muddying up" each other signals. But it seems since the systems are already in deployment that they have overcome most of the glaring obstacles.
For my own role-play purposes... Sometimes I delete the bearing ambiguity for the LA subs TA and then stream both the starboard and port arrays at the same time to simulate the twin-line system.... . Does wonders for the "clarity" of the taticaly picture.
Does anyone agree with me that the SW and/or VA probably has more than 2 TA or at least the capability to fit more than 2 TA. 2 thru the designated TA fins at stern, and maybe another couple thru the aft dive fins like the old LAs. Seems only logical, whey else would the designers decide to bite that extra drag/noise penalty in creating two more seperate aft planes.... (of course it could be to the reason of "upgradeablility" where the 2 extra pylons are somehow more easily/cheaply serviced or upgraded than TA that run thru the dive planes..... just speculation) |
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LuftWolf
Joined: 09 May 2005
Posts: 1872
Location: Free New York
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| Posted: Sun Apr 09, 2006 1:17 pm Post subject: |
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I don't think the 688/688i carry enough processing power to perform the necessary calculations... considering the SW was built without utiziling COTS from scratch (the TB-29 currently on the 21/22 are of the legacy variety as far as I can tell), I'd say it's the same for the 21/22 (JC probably has more significant COTS implementation so may already be utilizing the TB-29A, the COTS variety of TB-29).
So, the issue of twin-TA utlization is more an issue of computing power than physics for US subs currently... so the ambiguity stays for US subs. Nice try though.   |
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Deathblow
Joined: 11 Sep 2005
Posts: 392
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| Posted: Sun Apr 09, 2006 1:32 pm Post subject: |
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| LuftWolf wrote: | I don't think the 688/688i carry enough processing power to perform the necessary calculations... considering the SW was built without utiziling COTS from scratch (the TB-29 currently on the 21/22 are of the legacy variety as far as I can tell), I'd say it's the same for the 21/22 (JC probably has more significant COTS implementation so may already be utilizing the TB-29A, the COTS variety of TB-29).
So, the issue of twin-TA utlization is more an issue of computing power than physics for US subs currently... so the ambiguity stays for US subs. Nice try though. |
COTS can handle it! The programs needed to continously update the old 688i software has been in place since 1997. The 688 software systems have been undergoing continuous upgrades for the last 9 years. The SW was designed with open-enough architecture to be amendable to rapid software/systems upgrades.
http://www.fas.org/man/dod-101/sys/ship/ssn-688.htm
| Quote: | | A-RCI is a four phased transformation of existing sonar systems (AN/BSY-1, AN/BQQ-5, or AN/BQQ-6) to a more capable and flexible COTS/OSA-based system. It also will provide the submarine force with a common sonar system. The process is designed to minimize the impact of fire-control and sonar system upgrades on a ship's operational schedule, and will be accomplished without the need for major shipyard availabilities. Phase I, which commenced in November 1997, will enhance towed-array processing. Phase II will provide additional towed- and hull-array software upgrades. Phase III will upgrade the spherical array, and Phase IV will upgrade the high-frequency sonar system on SSN 688I-class submarines. Each phase will install improved processing and control and display workstations. The current installation plan completes all SSNs through Phase III by FY03. |
Processing power not a prob. Bearing ambguity.... going down! |
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LuftWolf
Joined: 09 May 2005
Posts: 1872
Location: Free New York
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| Posted: Sun Apr 09, 2006 1:44 pm Post subject: |
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Yes, but SCS has modelled the non-COTS version of Western platforms.
I can't change that without altering the interface heavily and making the western platforms so VASTLY superior to the russian units that it wouldn't be worth playing much... my guess is with full COTS implimentation, the US acoustic superiority over the Russians is probably at least as great as during the height of the Cold War pre-Sierra class.
But again, I'm wildly speculating... |
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Deathblow
Joined: 11 Sep 2005
Posts: 392
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| Posted: Sun Apr 09, 2006 2:13 pm Post subject: |
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I'm not trying to be argumentative...oh wait, yes I am 
The currest LW&A is using a TA system that wasn't in place until 2002, and the Mk54 that wasn't slated to be deployed until 2003, both post-COTS (1997), so a 2005 launched twin-line array system isn't that much of a strecth....and besides.... those UI look pretty COTS to me, especially the SW.
Come on, you know you want to try it.... ... just click off the "mirrored" contact in the DWEditor. Come'on... everyone's doing it, you'll like it, don't you want be to cool, like the cool kids.
Go West!! |
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LuftWolf
Joined: 09 May 2005
Posts: 1872
Location: Free New York
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| Posted: Sun Apr 09, 2006 2:35 pm Post subject: |
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Nope, no more help for Western platforms in DW as far as I'm concerned.
Not until the Russians start actually making competitive subs... so never.
There should be some reason to actually play the game, rather than just decide who wins in the game lobby (although five out of six players taking SW's in dives is no fun as it is...). |
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Deathblow
Joined: 11 Sep 2005
Posts: 392
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| Posted: Sun Apr 09, 2006 3:07 pm Post subject: |
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Fine. :shifty: Pooh. Not trying to imbalance the game, just a great sonar system is a great sonar system... and resolving bearing ambiguity is one of the more boring parts of the game IMHO, I'm glad to be rid of it (on my personal modded version).
| Quote: | | Not until the Russians start actually making competitive subs... so never. |
*awaits Kapitan's wrath of spam*
Well they do have the Kilo and now Lada, quiet as silent death, which is what has made these major sensor improvements necessary in the first place (for nukes that is). When in the littorals, and coupled with a AIP, the nukes are at some pretty big disadvantages.... SSK no longer as dependent on disiels and speed not been the issue in the littorals, super sensors are the only thing keeping the nukes "above water. :hmm: "
... hm... I guess what would *really* make it "even" is if SSKs began being modeled ingame with AIP...:hmm:. Whole different ball game then. *sigh* but once again we are at the "but the engine doesn't allow that* problem as always, deja vu. |
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LuftWolf
Joined: 09 May 2005
Posts: 1872
Location: Free New York
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| Posted: Sun Apr 09, 2006 5:02 pm Post subject: |
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The littorals are of course a different issue... not particularly well modelled in DW. But as it is, in bad sonar conditions in DW things are pretty well balanced depending on how the mission is set up.
In any case, I was thinking specifically about deep water situations, where the Akula is at disadvantage all considered against SW and is close to 688i in the game and is actually at a considerable disadvantage to both 688i and 21 in real life now.
Diesel subs and shallow water are a whole different issue.  |
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Wim Libaers
Joined: 21 Sep 2001
Posts: 396
Location: Flanders
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| Posted: Sun Apr 09, 2006 5:44 pm Post subject: |
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| To eliminate the ambiguous bearing, I think you'd need sufficient lateral separation, which is probably hard for subs. Range determination would be easier with two TA's streamed to different lengths, and that's probably a more significant advantage as it's harder to be sure about that. Bearing only requires one turn. |
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Deathblow
Joined: 11 Sep 2005
Posts: 392
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| Posted: Sun Apr 09, 2006 5:47 pm Post subject: |
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Bah, deep water conflicts are a thing of the past. When is the last time a "my giant fleet versus your giant fleet" conflict was ever plausible... about 15 years ago. Littorals is where its at. Then again, the littoral modeling in DW is *sigh* :nope: . Can't even figure out how to get the AI subs not to bottom out. :8 .
Although "simulation" and "balance" are sometime mutually exclusive, if the Akula needed some "boosting" it could alwasy be given the Squall Advanced version, something that I was arguing for a while back, which is toted to have a burst, then slow and search mode. |
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