The Myopic Tendency.

[Bellman]

At a time when we welcome game mods which reduce the range of some game sonar systems, perhaps we should
pause to reflect upon recent UK official public announcements:

Royal Navy:

''Also included as part of the programme, is the introduction of the fully integrated Sonar 2076 composed
of a bow, flank and towed array sensor. Captain Hughes added “Its performance is greatly enhanced over that
of current equipment fitted to attack boats. A good analogy for the performance of Sonar 2076 is that if
the submarine was in Winchester it would be able to track a double decker bus going round Trafalgar Square.

HMS Torbay has now been fitted with this new sonar developed by Thales Underwater Systems Limited which
contains 13,000 sensitive hydrophones and has the equivalent processing power as 60,000 PCs.

HMS Trenchant is the next submarine to complete the update.She is due to be ready for operations later this year.''

http://www.royal-navy.mod.uk/static/pages/4783.html

Now Winchester to central London is 60 miles or 52 nm OK your thinking like me - Spin ! But actualy this may be
a bit of usual UK 'reserve' - look at this:-

Ministry of Defence.

''Sonar 2076 is one of the most advanced sonar devices in the world. It has the power equivalent to several
hundred home PCs and can track the movement of small objects from hundreds of miles away. As well as the
reactor core and sonar suite, workers at Devonport will be making other modifications to HMS Triumph to
improve her combat systems and make her less easy to detect.''

http://news.mod.uk/news/press/news_h...wsItem_id=3674

Note - ''Hundred.....s '' !

If this is the new sonar reality, I wonder whether we shall need to revisit this question of range again when the
full implications of the SAS SSP 1.03 changes become clearer ? :hmm:

[JamesT73J]

Some odd comparisons there. 'Power equivalent to home PC's' is a new measure to me; are they talking about wattage or execution speed?

There's also the question of what the target would be. If you go out in a fibreglass sailboat you can sometimes hear far off merchies through the hull like they're next door, and they can be 10 miles away, same with speedboats.

I guess a quiet target would be a different proposition.

[SeaQueen]

As usual, all quotations of sonar range estimates need to be taken with a grain of salt. They depend on the properties of the water column, the bathymetry, etc. With sonar, it's perfectly realistic to get 2NM detection ranges. It's also perfectly realistic to get 200NM detection ranges. It all depends. That's what makes ASW so hard. There's so much you just don't know.

[Bellman]

SQ I am sure that most here appreciate your valid points but I do not recall, correct me if I'm wrong, reports
of in-game detections at those kind of ranges. Not that that is particularly pertinent as what the quotes reveal
is that real extremes may exceed our general gameing understanding. My point isnt that such extremes are
even typical but what is it reasonable to take as the modal range parameters ?

Have we become, with LwAmi 3.0, a trifle myopic when about to enter the new SAS 'playing field' post 1.03 Beta ?

I am sure that there are 'backroom ' folk who (rightly) would prefer to keep a discreet mist in front of our eyes and
will be very content that we simulate under possibly excessively restrictive conditions. :hmm:

[LuftWolf]

Well if it makes you feel any better, with the exact same database LWAMI database, varying only the SSP, I've seen detection ranges on the same submarine from over 35nm to 4nm.

1.03 greatly increases some detection ranges (like in a CV) and reduces some others.

Overall, the balance of this is to increase the ranges for more tactical situations.

[Bellman]

Thats really good news LW

[TLAM Strike]

With three Convergence Zones you could get a ~100 mile detection (33 miles each 33x3=99 round up) and I see that happening with noisy merchants and biologics. I’ve heard that 1960’s GUPPYs could hear a snorkeling sub at 20 or 30 miles with their new hull mounted SONARs and they have had 55 years to improve since then.

[SeaQueen]

Originally Posted by Bellman

SQ I am sure that most here appreciate your valid points but I do not recall, correct me if I'm wrong, reports
of in-game detections at those kind of ranges. Not that that is particularly pertinent as what the quotes reveal
is that real extremes may exceed our general gameing understanding. My point isnt that such extremes are
even typical but what is it reasonable to take as the modal range parameters ?

In sonar there isn't really any modal range, according to which one could assign some kind of definite range law for detection. In professional computer models of warfare, characterizing sonar performance is actually one of the most difficult things to do intelligently. It's very hand-wavey.

Sonar performance is so potentially variable, even within a single location, that to pick out any one range with one sensor and say, "this is what you're going to get," is absurd. Ask any sonar technician. What you get is what you're gettin' depending on where in the world you are, you might not get that tomorrow. Even on a very good system, sometimes you'll see amazingly long distances, sometimes, you'd almost be as good with a pair of binoculars looking for a periscope.

Have we become, with LwAmi 3.0, a trifle myopic when about to enter the new SAS 'playing field' post 1.03 Beta ?

Not necessarily. Depending on where you are, acoustic phonemomena like multiple convergence zones and super-duper surface ducts that lead to these kinds of very long ranges aren't really a big deal, because they're rare.

You especially don't see that sort of thing too often in most contemporary theatres. That's sort of what people are grappling with now. A lot of what was responsible, back in the 80s, for NATO forces doing so well in ASW was not just that the Soviets made loud boats and couldn't train enough in them. It was the oceanography. Northern lattitudes are just more friendly to sonar.

Currently, the places they're thinking about are in tropical or subtropical waters with a high sea surface temperature, so most places, except the very deep, are strongly bottom limited. Multiple convergence zones is something you'd generally think about in more northern lattitudes.

Ideally, yes, it'd be really cool if they could import some kind of global climatology into DW so that we wouldn't have to rely on the (inaccurately portrayed) SSPs that we have in the game, and capture a lot more of the variability of sonar performance. Unfortunately, I don't see that happening. To REALLY build a detailed sonar model, requires some pretty heavy duty computing just to run it. Even then it's not accurate. All the existing research-grade sonar models to date are 2D. The ocean is 3D. People can build careers around making better sonar models.

I am sure that there are 'backroom ' folk who (rightly) would prefer to keep a discrete mist in front of our eyes and
will be very content that we simulate under possibly excessively restrictive conditions. :hmm:

There's nothing classified about modeling sonar. The people at SACLANT (NATO's big underwater acoustics lab), some people at SAIC (the company that makes the Navy's sonar models), and a guy at MIT recently published a book on it. It's called Computational Ocean Acoustics. It's fun stuff.

What IS classified is specific performance figures for specific systems. That's why everything you see out there is very vague and tends to lack the necessary qualifiers for us to actually make useful estimates of how good the sonar model in DW is.

DW has a lot of depth to it. It has as much depth as anything I've seen out there, in fact. Some things it does well, some things it doesn't. Have fun with it. There's a lot you can learn with it.

[Bellman]

Thanks SQ that was a real nice post and helps me to come to terms and adjust to my sonar 'short sightedness.'

SQ:

that to pick out any one range with one sensor and say, "this is what you're going to get," is absurd.

I dont think I suggested that ? I was referring to the modal ranges implicit in the LwAmi mod sonar systems desensitising.


SQ:

What IS classified is specific performance figures for specific systems. That's why everything you see out there is very vague and tends to lack the necessary qualifiers for us to actually make useful estimates of how good the sonar model in DW is.

If we combine computing/software 2D constraints with the ''classified'' performance specificity I would have
thought that inherent in such combo is the selection of in-game performance limitations and system 'modality' ?

SQ:

Computational Ocean Acoustics.

Yet again you add to my reading list - youre becoming expensive . Not looking for a Phd.

Yes thats ''fun'' to miss - the ''Computational'' bit will bring on some real.............Magooism.

Anyways thanks again for your thoughts, which I appreciate.

[Kapitan]

if sonar is designed to listen then thats what it does sound travels faster than light in water due to the closeness of molocules hence why the speed to sound equasion does not work in water or space.

if you get a glass and put it in the water and put your ear to it you can hear a ship miles away, and the guy who said that lived almost 150 years ago so if he can hear a ship with a glass im dam sure a sonar can hear a ship a hundred miles away

[MaHuJa]

Originally Posted by Kapitain

if sonar is designed to listen then thats what it does sound travels faster than light in water due to the closeness of molocules hence why the speed to sound equasion does not work in water or space.

if you get a glass and put it in the water and put your ear to it you can hear a ship miles away, and the guy who said that lived almost 150 years ago so if he can hear a ship with a glass im dam sure a sonar can hear a ship a hundred miles away

Light travels faster than sound, even in water, but not as far.

Also, please explain what the "speed to sound equasion" is, and... well... how do I put this... more or less why something not true at all affects it?


As for the leonardo quote (I believe it was him) I don't think the 100 miles is accurate, more than as "far away" "over the horizon" or... well, you get the picture. And even he certainly had little clue of how sound works in water, compared to what sonar operators do today.

[Kapitan]

not 100% sure about the speed v light in water equation think it goes something like this (dont quote not absolutely sure)

Speed is distance X time taken
Light distance X time taken

compaired

works out that sound travels farther and faster in water than light

the more dense the object the less speed light travels

[TLAM Strike]

Although the speed of light is less than c in water it’s not slower than sound, electrons yes (Cherenkov effect) but not sound.

C = 299,792 Km/s
SOL in water = 218,400 Km/s
SOS in water = 1.5 Km/s
SOS at +29,000 meters = 0.3 Km/s

[SeaQueen]

If we combine computing/software 2D constraints with the ''classified'' performance specificity I would have
thought that inherent in such combo is the selection of in-game performance limitations and system 'modality' ?

I guess I'm not sure what you mean by "modality."

[drEaPer]

i dont like smattering