Broadband vs narrowband sonar

[Shadowmind]

I recently tried the RA mod and it models broadband vs. narrowband contacts differently than the LWAMI mod. In LWAMI 3.08 it seems that contacts appear on narrowband long before you can pick them up on broadband. I didn't think about it much at first and I've been playing with the LWAMI mod for several years.

Recently I tried the RA mod and liked the idea that contacts showed up in broadband long before I could accurately detect their tonals. So I started to dig into it. I've never been on a sub, I don't claim to be a sonar expert, but I do a lot of image/signal processing in my job. So I threw together some graphs to prove out my concept.

It was easier if I just threw everything into a PDF (http://sites.google.com/site/nlbutts/Home/SonarTest.pdf) and linked to it. Let me know what you think. Am I totally off base. Is there some fundamental concept I am missing?

Thanks.

[Dr.Sid]

First I think you get wrong conclusion in this: signal only consist of tonals. It's not true, it also consist of wide-band signals, ie noises. Those are hard to see on NB display but they add to total BB signal strength. This plays into BB sooner then NB theory.

Also you should use some different displays for NB .. those from matlab indeed does not look to good and the signal indeed can't be seen very well. Consider longer time window averaging which will cancel noise, also the noise in the sea is not uniform, nor are the tonals. So there can be many different situations.

If you had some really strong one high frequency tonal source, NB would help to differ it from mostly low frequenct background noise.

There is many BB sound sources in the sea. Only NB or aural evaluation can ID them as submarine.

I guess NB is first to identify contact as submarine. But BB could be first to make detection at all, with high false contact ratio. Also most books/movies follow this scenario.

But then I'm not submariner.

[Rip]

I will be a little vague to make sure I don't get too close to the line, but in general each platform has different NB to BB detection characteristics are different for types of contacts. Some specific tonals carry much better as well although they often don't get you much ID wise.

The rules change a good bit in different enviroments. When you are focusing on a specific target a good sonar team will know what tonals they will pick up in what order. They will also have some idea at what point they might gain BB contact.

[Shadowmind]

I will be a little vague to make sure I don't get too close to the line :hmm: Not sure what you mean by this. I didn't think my question was getting into classified areas.

The rules change a good bit in different environments. When you are focusing on a specific target a good sonar team will know what tonals they will pick up in what order. They will also have some idea at what point they might gain BB contact.
So, in general, you would most likely pick up a contact in broadband first, and then over time start to sort out the tonals? Is there a difference in the sphere sonar vs towed arrays? One thing my simulation didn't model is the ability of different sensors to pick up signals. I've read that towed arrays, with the longer pick up area, is better at picking up lower frequency signals. But does that translate into a better ability to pick up tonals?

Thanks, This stuff just fascinates me.

BTW: Dr. Sid, I've enjoyed messing around with your ray tracing programs. They are very interesting.

[Dr.Sid]

Tonals come in all frequencies, that is not array dependent. Generally low frequencies travel far away .. but that is also the reason why there is more low frequency noise in the sea. So again, no general rule I guess.

In DW you first pick 50/60 Hz tonal .. that is more in towed array frequency range, rather than in sphere array range. But then DW does not take noise into account in NB.
Also, as I heard, many subs use 400Hz for basic electricity lines, because all the transformers can be much lighter and smaller like that. That would shift the tonal more into SA range, and away from dominant low frequency background noise.

PS: glad you enjoyed my tool :88)

[Bubblehead Nuke]

:hmm: Not sure what you mean by this. I didn't think my question was getting into classified areas.

There is a MAJOR problem when you have served on a sub. You can, by admitting or dening something, PROVE something and thus compromise security.

It is the the difference of what you think you know and what you KNOW you know.

I might not tell you the truths, but by telling you want is wrong, tell you what is really right.

Does that make sense?

[Pingjockey]

I have to agree with bubblehead nuke... There are a lot of things you can't talk about...

Now back to the discussion, Rip has it right on the head, a good sonar team will what there looking for...

[Rip]

I will be a little vague to make sure I don't get too close to the line :hmm: Not sure what you mean by this. I didn't think my question was getting into classified areas.

The rules change a good bit in different environments. When you are focusing on a specific target a good sonar team will know what tonals they will pick up in what order. They will also have some idea at what point they might gain BB contact.
So, in general, you would most likely pick up a contact in broadband first, and then over time start to sort out the tonals? Is there a difference in the sphere sonar vs towed arrays? One thing my simulation didn't model is the ability of different sensors to pick up signals. I've read that towed arrays, with the longer pick up area, is better at picking up lower frequency signals. But does that translate into a better ability to pick up tonals?

Thanks, This stuff just fascinates me.

BTW: Dr. Sid, I've enjoyed messing around with your ray tracing programs. They are very interesting.

The question didn't just the answer could. But didn't.

Some times broadband first but platforms that have been built with acoustic silence in mind will be seen with NB first and may in fact never give much BB levels. The TA is great at low freq tonals and the sphere at the higher freqs. The hull array is middle of the road. A lot can be gained by looking at what tonals are picked up first and what ones are missing or very week. You can even get to the point of knowing about a defect or special equipment on a specific platform and being able to identify/track a specific ship based on data collected by others when recording that platform. Digital tapes of all acoustic and electronic intercepts from a boat are gone over not just by ships crew but by other parties long after the mission has passed.

[Bubblehead Nuke]

Just FYI, for those of you who think there is not a line that we can not cross?

I was contacted some months ago officially (as in certified mail and a phone call to my unlisted number) that I was too descriptive on a few topics and was ... um.. reminded.. of the penalities of information disclosure.

I have been out for over a decade now and even someone like me can still compromise OPSEC if we say too much.

I was a lowly nuke who just pushed the sonar dome & torpedo room around.

These Sonar weenies er.. Techs, now if they cross the line they get REAL serious. They would probably get a knock on the door.

[XabbaRus]

Wow, I always figured this forum would be watched but how did the figure out the real person behind Bubblehead?

I suppose the did and I.P. check and traced it that way aswell as you saying which sub you served on and when.

Respect to you guys, you have helped a lot with the understanding.

[Dr.Sid]

After reading related chapters from Uric's Princleps of underwater sound, Rip's statement looks solid. It's simple matter of what is dominant in the signature.
Without cavitation NB signals dominate total radiated spectrum, even for slow moving surface ships. NB will have major advantages, by telling what is noise and what is signal.
With cavitation (which is normal for surface ships at all but minimum speeds) the broadband noise dominates and covers all the lines. In such case NB will be of little advantage, if any.
Still exact amounts are mystery .. and big no-no from experts I asked. :arrgh!:

[Shadowmind]

A lot of this information I've pieced together from various books I've read. It amazes me that some of this stuff is even remotely sensitive. For example the BSY-2 on the Seawolf uses a network of 70 68030 processors. 68030 are ANCIENT! These are the processors that were in the original MACs. The processors we use at work are orders of magnitude faster. I guess my point is, the technology isn't that special and doesn't need to be so secret, but the application of the technology should be. I.E. missions and operations.

Anyway, this is all off my original topic. Thanks Rip and Dr. Sid. I think that fills in the missing pieces in my mind. But now I am going to be compelled to create a little simulation to prove out these concepts. That curiosity thing just sucks some days.

[Hitman]

I guess my point is, the technology isn't that special and doesn't need to be so secret, but the application of the technology should be. I.E. missions and operations.


I don't think that the technology itself is so secret, it's the real world efectiveness of it what is top secret, i.e. what they can or can't detect, what they can or can't hide, etc. Processor power is one thing, but that power might be sufficient if the data the sensors can collect is already detailed enough, or inversely, more processor power might be unnecessary because the current sensor technology can't provide more accurate data to be processed.

[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....:D

[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. :arrgh!:

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]

I guess my point is, the technology isn't that special and doesn't need to be so secret, but the application of the technology should be. I.E. missions and operations.

I don't think that the technology itself is so secret, it's the real world efectiveness of it what is top secret, i.e. what they can or can't detect, what they can or can't hide, etc. Processor power is one thing, but that power might be sufficient if the data the sensors can collect is already detailed enough, or inversely, more processor power might be unnecessary because the current sensor technology can't provide more accurate data to be processed.

Also not all processing is done by those. Not to mention not all signal processing is done by actual processors. Just because the processing power of the early space flights was small compared to what is used today, the problems that had to be calculated and dealt with were anything but simple. Don't get me wrong the digital processing helps but the most classified parts are more related to what we can do and how, not how complex the problems that are faced are. At one time we were forbidden to even say the word Tritium(sp?). That is why if you listen to Sailor Steve's video he took while we rode to Galveston in Neal's car I was telling a story that concerned tracking operations. That was probably cloder to the line than I would normally venture, only because I didn't realize he had audio on his camera. Thankfully I was wise enough to leave out location and time details that probably kept it far enough from "the line" that I can sleep with both eyes closed.

Rip

[Rip]

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. :arrgh!:

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.

[Shadowmind]

Also not all processing is done by those. Not to mention not all signal processing is done by actual processors. Just because the processing power of the early space flights was small compared to what is used today, the problems that had to be calculated and dealt with were anything but simple. Don't get me wrong the digital processing helps but the most classified parts are more related to what we can do and how, not how complex the problems that are faced are. At one time we were forbidden to even say the word Tritium(sp?). That is why if you listen to Sailor Steve's video he took while we rode to Galveston in Neal's car I was telling a story that concerned tracking operations. That was probably cloder to the line than I would normally venture, only because I didn't realize he had audio on his camera. Thankfully I was wise enough to leave out location and time details that probably kept it far enough from "the line" that I can sleep with both eyes closed.
Rip
No, I'm sure those processors aren't the extent of processing capability on a sub. I just had to smile when I read that. It just reminds me how far technology has come.
I think it would make far more sense to use an array of FPGA's to perform the signal processing. It would allow you to have a massive parallel DSP.

Rip, thanks for "Waking the line" on your explanations. It's nice to know our tax money goes towards really cool technology that we don't have the right to know about :D

Dr. Sid, I see you are working on an open-source cold war sub sim. How do you plan to model the sonar? Have you started on the work yet?

[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.

[Dr.Sid]

Hopefully I get more time over Christmas so I'd like to find those 3ds bugs. Most probably I just ignore some sections which did not appear earlier.

[XabbaRus]

It's odd as they work in DW fine after being converted to J3D.

I'd have thought if there was a problem with the model DW would have shown it up.

[Dr.Sid]

There for sure is no 'problem' with those files. They just use some feature I don't support at the moment.

[Deamon]

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.

[Dr.Sid]

That's actually why I like modern subs .. because you can play with sonar so much :arrgh!:

[SeaQueen]

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]

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

[Dr.Sid]

Honestly I don't know much yet. I did not discuss this much with anyone.

By environment I mean background noise. This seems to be covered quite well in Urick, and there is no technical problem (I know of).

As for false targets .. there should be more bio targets, rocks, ice peaks or wrecks, all with both passive (water flow and eddies for silent ones) and active, and magnetic and so on when we get there.

Also for active the bottom reflection should be made better I think, especially if it's rocky, there should be a chance to hide at the bottom (I guess).

Any comments are appreciated.

[Shadowmind]

Dr. Sid, I agree with all of your ideas for more realistic sonar environment. A few interesting items, would be the ability to detect other contacts from the reflections from other vessels active sonar emissions. I wouldn't expect a real accurate range based on the fact that the ownship wouldn't know the exact time the active pulse was transmitted, but you should be able to at least detect reflections and get a bearing.

You mentioned you wanted to use ray tracing, but it is too expensive. Maybe there are some optimizations/compromises that can be made. For example, only perform the ray-tracing from a noise source to ships that may be listening. For example, if there is a sub X nm from the noise source, but the sub is traveling too fast to pick up the signal, then you could optimize that ray away.

I know NVidia did a demo recently of a real time ray traced scene. I don't recall the resolution, but it was higher than 1280x1024. Although I believe that was on a quad GPU setup.

I guess my point is, it would be nice to built the engine with the ability to support ray tracing and a table based system. If you can't hit the performance goals on a certain platform, you fall back to the table based system. But if you have a powerful enough system, you could use the ray tracing scheme.

[Dr.Sid]

There is absolutely no need for raytracing in the first place. It would not be better then the tables, since the tables itself would be based on raytracing. But raytracing alone is only valid for high frequencies and idealistic conditions. It's also good for estimating convergence zone range for example, and there could be such tool accessible from sonar station, but generaly it's only one solution for part of the problem.

Here I have to take all phenomemons I want to simulate, and find best approach.

Also realtime is not enough, since we want to use time compression, and lot of it.
And 'every listening platform' may be array of 50 sonobuoys .. the sonar really has to be done as fast as possible.

Look at DW . .even on my core duo 2.3 GHz it mostly does not manage to go 32x, if there is more platforms, and it fakes sonar in great way, especially for AI.

[Deamon]

Also for active the bottom reflection should be made better I think, especially if it's rocky, there should be a chance to hide at the bottom (I guess).

Any comments are appreciated. I have read in a WWII u-boat book about one occasion in the norwegian sea where a british destroyer come close to the u-boat while pinging but the commander of the u-boat wasn't concerned about it at all cause the bottom was rocky and the depth was shallow, iirc, indicating that his asdic was useless cause it gets echos from everywhere on the bottom.

[SeaQueen]

There are technical problems in terms of getting data. Even though theoretically we know how to model it to some reasonable approximation, the next question is, which numbers do you stick into the equations to make them work?

One of the things I REALLY wish for is actually more control for the scenario designer of the environment. I mean... suppose you just assumed that omnidirectional noise level was a Gaussian distributed random number with some mean, m and some standard deviation, s. It'd be nice if the scenario designer could fill those values in. I'd have to really review Urick's chapter on the noise level. The real issue is not so much how to model it but more what options to include so that the system is as flexible as possible and still meaningful to people. Ya know? I come at it from the direction of a sonar geek, but someone else might say, "I don't want to stick in a mean and a standard deviation, I just want to say it's raining or there's a lot of shrimp snapping." That to me, though limits it's flexibility. To a certain extent, giving more control to the scenario designer also eliminates the need for data. It's essentially saying, "you can have any values you want anywhere, if you have some oceanographic database to justify it, all the better." There might be some default values for strategically interesting areas that we've researched, but even those should be changable.

Biological noise is complicated because it tends to be concentrated in specific areas but it shouldn't be constrained to them either. Off Cape Cod, for example, there's a very rich Marine preserve where there's tons of whales, dolphins and the entire ecosystem to support them. But it's also seasonal, so doing anything other than leaving it up to the user to include them means you need data. Do you know the distribution of whales globally as a function of time? What about shrimp? Seals? Croakers? Lobsters? Scallops? All fish with swim bladders? The list could be as long as you want.

The "bottom reflection" or reverberation issue is actually fairly complicated. Depending on sea state there's also surface reverberation. There's actually computer models built specifically for reverberation. I imagine that in order to get the desired effect you'd have to take into account grazing angle issues. You'd also have to worry about things like depression/elevation angle on the sonar set itself. Pointing the sonar beam pattern down might mean less reverberation, although less direct path range, pointing it up might increase reverberation but you also get more range. If you're planning to do stuff with just lookup tables, I'm not quite sure how to make this work. To make matters worse there's also volumetric scatterers in the water column that contribute to reverberation as well, so it's not just the bottom. You're also limited by the available data again.


Honestly I don't know much yet. I did not discuss this much with anyone.

By environment I mean background noise. This seems to be covered quite well in Urick, and there is no technical problem (I know of).

As for false targets .. there should be more bio targets, rocks, ice peaks or wrecks, all with both passive (water flow and eddies for silent ones) and active, and magnetic and so on when we get there.

Also for active the bottom reflection should be made better I think, especially if it's rocky, there should be a chance to hide at the bottom (I guess).

Any comments are appreciated.

[Bubblehead Nuke]

There are technical problems in terms of getting data. Even though theoretically we know how to model it to some reasonable approximation, the next question is, which numbers do you stick into the equations to make them work?

If we get 10% of your comments in the comsubsim, it will be better than what we have now.

Just as I, a nuke, will have to settle for approximations in ownship noise levels and the factors that control them, you as a sonar tech, will have to settle for a little less as well. Granted, I think that sensor data and the variables that create and modify them should be done to a greater extent. This is after all, a sensor sim.

[Frame57]

There are technical problems in terms of getting data. Even though theoretically we know how to model it to some reasonable approximation, the next question is, which numbers do you stick into the equations to make them work?

If we get 10% of your comments in the comsubsim, it will be better than what we have now.

Just as I, a nuke, will have to settle for approximations in ownship noise levels and the factors that control them, you as a sonar tech, will have to settle for a little less as well. Granted, I think that sensor data and the variables that create and modify them should be done to a greater extent. This is after all, a sensor sim.How true a statement, because if this were a "Subsim", where are the liberty ports and the girls...?:D

[SeaQueen]

Just as I, a nuke, will have to settle for approximations in ownship noise levels and the factors that control them, you as a sonar tech, will have to settle for a little less as well.

Actually, I'm not a sonar technician, I'm a physicist who happened to fall into the ASW business by accident. Don't short change me on nuclear stuff either. Something I think would actually be a fun addition to a nuclear subsim would be some reactor physics. Like... I know there's interesting transient states you can get the reactor in when you change throttle settings and you have to make a control rod adjustment. I sort wonder how to put that into a subsim such that there might be an "engineering panel" or something where you could manually adjust the throttle of the submarine.

[SeaQueen]

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]

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."

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.

[Rip]

There are technical problems in terms of getting data. Even though theoretically we know how to model it to some reasonable approximation, the next question is, which numbers do you stick into the equations to make them work?
If we get 10% of your comments in the comsubsim, it will be better than what we have now.

Just as I, a nuke, will have to settle for approximations in ownship noise levels and the factors that control them, you as a sonar tech, will have to settle for a little less as well. Granted, I think that sensor data and the variables that create and modify them should be done to a greater extent. This is after all, a sensor sim.How true a statement, because if this were a "Subsim", where are the liberty ports and the girls...?:D

and field days?

:cry:

[Rip]

Just as I, a nuke, will have to settle for approximations in ownship noise levels and the factors that control them, you as a sonar tech, will have to settle for a little less as well.
Actually, I'm not a sonar technician, I'm a physicist who happened to fall into the ASW business by accident. Don't short change me on nuclear stuff either. Something I think would actually be a fun addition to a nuclear subsim would be some reactor physics. Like... I know there's interesting transient states you can get the reactor in when you change throttle settings and you have to make a control rod adjustment. I sort wonder how to put that into a subsim such that there might be an "engineering panel" or something where you could manually adjust the throttle of the submarine.

Cool things with coolant pumps as well, but I fear some of the cool stuff I am thinking of is still pretty classified so I will steer clear of the subject and let the boys that do that for a living comment if they dare.

Prepare to shift propulsion to the EPM. Prepare to snorkel. :rock:

[Neptunus Rex]

All Ahead Flank!

"BANG, BANG"

Answering All Ahead Flank.

[Bubblehead Nuke]

All Ahead Flank!

"BANG, BANG"

Answering All Ahead Flank.

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BANG, BANG