Broadband vs narrowband sonar

[Pisces]

Besides, they probably used 70 of those (simple) processors at a couple of 10s of MHz, instead of lets say a more modern (single) P4 cpu at some Ghz, to make the processing parallel instead of serial.

[Frame57]

We used to have little books called piping tabs which had every major system laid out in great detail. We used these when we had to shut down a system and tag other valves etc... so they would not be operated in order to maintain safety and perform whatever pm or repair necessary. I went to a garage sale and in a book bin for 50 cents was a piping tab for the Richard B. Russell SSN-687. I bought it from the lady and asked her where she got it and she told me it was her ex husbands who was a Mare Island naval shipyard worker.

At my exiting interview i was told that a 20 year federal prison sentence happens to those who would be caught with schematics of a nuclear submarine.

Even myself here on this subsim site, I want more accurate details about stuff especially sonar when it comes to playing this game, but not at the expense of having classified info being divulged. But now about those Russian boat (he he) I will take all the info I can get, too bad we do not have a Russian sub sailor here who we can pump for info....

[Dr.Sid]

Sometimes even you US bubbleheads tell more about Russian subs then about US subs. Sure you know little of them, but then it's much less secret. So I would like to see Russian sonar chief to tell me about typical 688 signature, since that is info no US mariner will give.

Anyway the game must be just so good, that it matches general knowledge, with some additional educational insight. It dos not have to be correct, as long as nobody knows what really is correct.

[Rip]

Originally Posted by Dr.Sid

Sometimes even you US bubbleheads tell more about Russian subs then about US subs. Sure you know little of them, but then it's much less secret. So I would like to see Russian sonar chief to tell me about typical 688 signature, since that is info no US mariner will give.

Anyway the game must be just so good, that it matches general knowledge, with some additional educational insight. It dos not have to be correct, as long as nobody knows what really is correct.

Well said. The fact that you could make a tonal you pick up vary in freq based on speed in the line of sight and using that to tactical advantage adds realism, the specific frequencies and the amount of shift not so much so. 98% of the really classified stuff would have zero tactical effect on how you operate your platform. Probably half of the remaining stuff that is classified can be guessed at effectively. No value in everything being exactly technically accurate.

[Bubblehead Nuke]

I have chatted with Dr. Sid about that very thing. As long as the CONCEPTS are fundementaly correct, who cares about the exact numbers.

The devil is how to give someone an understanding of the engineering that goes into a sub without 'crossing' the line'.

To help with the sub handling models, I have researched and found a few choice books that are interesting reading to an aspiring sub sim designer.

[Dr.Sid]

Main difference compared to DW is the delays induced by finite sound speed will be correctly simulated, to such extent, that it alone will allow active sonar simulation.
Each sound will 'travel' and 'hit' other platforms in correct order, where it will get detected (for passive) or bounced (read new sound event will be generated) for active sonar. This is general mechanism how sound will get from source to listener.

This is actually what I'm working on in the moment.

As for transmission loss, layers, channels and so on, nothing like raytracing is possible because of huge amount of computing it needs, so it will be just lookup tables based on range, depth of listener, depth of target. However I plan to have these changing fluently with daytime and location. I'd also like to have let's say 3 frequency ranges so different frequencies can react differently on sound speed profile.

As for sound source, it's clear DW's 4 constant lines per platform is huge simplification, and I plan to have quite complex sound sources, since it's cheap. So there will be many components, each related to expected cause, and variable not only in amplitude, but in frequency too, where it should be. Propeler noise, flow noise, gear whine, pumps, steam noises, generators, you name it. And of course, correctly simulated transients, which will generaly be samples played (and heard on listener side) when some specific event happens (like torpedo tube opened, or coin dropped :rotfl.
This will make identification much harder and description of sub wont be 4 frequencies. Expect long process of guessing and ruling out. You should be able to tell 'this is ruskie sub' quite soon, while it might be hard to tell if it's delta III or delta IV. Anyway this rich possibilities will easily allow each hull to be slightly different.

As for listener side gear, it will just look slightly more complicated, there is nothing much wrong with it in DW, except it's simplistic at some details.

Of course there will also be MUCH more false contacts, and there will be better environment simulation.

[XabbaRus]

Sounds good Sid,

I have a week and a half off over Christmas....so I'll send you some more subs.

If you can let me know what happens with the surface models where they go weird on you I could try and mitigate it in the model before I send it.

I'd like to make a big push with this and get you some nice surface vessels.

[Deamon]

Originally Posted by Dr.Sid

Main difference compared to DW is the delays induced by finite sound speed will be correctly simulated, to such extent, that it alone will allow active sonar simulation.
Each sound will 'travel' and 'hit' other platforms in correct order, where it will get detected (for passive) or bounced (read new sound event will be generated) for active sonar. This is general mechanism how sound will get from source to listener.

This is actually what I'm working on in the moment.

As for transmission loss, layers, channels and so on, nothing like raytracing is possible because of huge amount of computing it needs, so it will be just lookup tables based on range, depth of listener, depth of target. However I plan to have these changing fluently with daytime and location. I'd also like to have let's say 3 frequency ranges so different frequencies can react differently on sound speed profile.

As for sound source, it's clear DW's 4 constant lines per platform is huge simplification, and I plan to have quite complex sound sources, since it's cheap. So there will be many components, each related to expected cause, and variable not only in amplitude, but in frequency too, where it should be. Propeler noise, flow noise, gear whine, pumps, steam noises, generators, you name it. And of course, correctly simulated transients, which will generaly be samples played (and heard on listener side) when some specific event happens (like torpedo tube opened, or coin dropped :rotfl.
This will make identification much harder and description of sub wont be 4 frequencies. Expect long process of guessing and ruling out. You should be able to tell 'this is ruskie sub' quite soon, while it might be hard to tell if it's delta III or delta IV. Anyway this rich possibilities will easily allow each hull to be slightly different.

As for listener side gear, it will just look slightly more complicated, there is nothing much wrong with it in DW, except it's simplistic at some details.

Of course there will also be MUCH more false contacts, and there will be better environment simulation.

Good stuff Dr.Sid. I am curious how much of this stuff you will be able to pull out. I planed to do the same back in the days for my cold war project before I switched to WWI. But even for my WWI sim, I still want to do it.

[SeaQueen]

Dr. Sid, how do you plan to do better environment simulation and false contacts?

[SeaQueen]

Originally Posted by Bubblehead Nuke

I have chatted with Dr. Sid about that very thing. As long as the CONCEPTS are fundementaly correct, who cares about the exact numbers.

That's so true. One of my pet peeves of naval simulations is how people obsess over all the techno-weenie details and end up missing the big picture. A good wargame should be about tactics and decisions. Details of specific numbers and knob twiddling should be secondary. They really only need to be in the ballpark because often the uncertainty on actual numbers is large and the impact of that uncertainty dwarfs the importance in terms of decisions than whether a given platform's source level at 138Hz is 120dB or 135dB.

[SeaQueen]

Originally Posted by Bubblehead Nuke

The devil is how to give someone an understanding of the engineering that goes into a sub without 'crossing' the line'.

As a general rule, my experience is that most of the engineering and science behind a given process is unclassified. I've never encountered anything purely engineering that was classified, except for things like how to manufacture radar absorbant materials and what not. The engineering of unique technologies that give the US a significant technological edge over the rest of the world are generally classified.

The laws of physics don't change across borders. It's no big secret how a nuclear reactor works, for example, or how beamforming works. You can find beautiful books on all of that. All of it is unclassified. Heck, we actually gave the technology to build nuclear reactors to Iran under that Atoms for Peace program in the 1950s under Eisenhower.

The problems pop up when people say, "here's how we do it specifically on this vessel, and oh, btw, here's some performance numbers."

[Bubblehead Nuke]

Originally Posted by SeaQueen

As a general rule, my experience is that most of the engineering and science behind a given process is unclassified. I've never encountered anything purely engineering that was classified, except for things like how to manufacture radar absorbant materials and what not. The engineering of unique technologies that give the US a significant technological edge over the rest of the world are generally classified.

The laws of physics don't change across borders. It's no big secret how a nuclear reactor works, for example, or how beamforming works. You can find beautiful books on all of that. All of it is unclassified. Heck, we actually gave the technology to build nuclear reactors to Iran under that Atoms for Peace program in the 1950s under Eisenhower.

The problems pop up when people say, "here's how we do it specifically on this vessel, and oh, btw, here's some performance numbers."

Oh, the physics is the easy part and no problem to get across or explain.

The actual details of power plant operation is not really a issue as it is far beyond the scope of any sim. Things like plant management and power constraints DO play a part as you can opt for low power/lower noise levels/lower max speeds vs high power/higher plant noise/higher max speed. Because of the nature of speed/drag/power curves there is no simple linear solution. You are able to make a trade-off that have a tangible tactical effect.

Since this IS a sim, these are things that need to be taken into consideration as they are a part of the operational equation. Unfortunatly, there is very little outside references into the operational considerations and tactical employement of a submarines. This is where those of us who have served try and give an insight without busting the rules.