Subject discussion: detecting a contact's depth

[suitednate]

It's obvious that in this game that you know a contact's depth but were/are subs actually able to determine the depth of a submarine contact? I only ask because I've played dangerous waters and sub command a LOT (both of which seem to set the standard for realism in a subsim) and there was no concrete way to determine a sub contact's depth....Unless I made a glaring oversight this whole time It was more of a calculated guessing game.

Thoughts anyone?

[PL_Harpoon]

Here are some posts from steam forums:

Real life Sonar Technician Surface, US Navy retired.
[...]
If anyone has any questions, that is why I made this post. I can answer any questions anyone might have.

While the game lacks the 'real' detail of sonar, subs and ASW prosecution, it models the 'fight' pretty damn good.

And a few posts later from the same guy (in response to a question aboud DEMON):

If you add all the features in all the submarine games you can play today, you are looking at maybe 1/16th of reality in our gear, equipment, sonar stacks and capabilities. So yes to your answer BUT what you 'play' in a game is not even close to how much more capable we are in reality.

Military tech is usually 20 years AHEAD of anything you will ever see or use in the civilian world.

I figured the same rule applies to depth difference.

[jenrick]

Not a submariner, never been in the navy, etc.

With that out of the way, I'd think you could utilize the various hydrophone locations on the subs hull to determined depth. Sound radiates as a wave, so different parts of the wave front will contact the hull at different times (probably miliseconds apart, but enough to matter). For example if the hydrophone on the top of the hull receives a certain sound before one located on the side of the hull, the contact is above the vessel. Add in some fancy math, and you'd have a fair guess of the depth of a contact.

[The Bandit]

Originally Posted by jenrick

Not a submariner, never been in the navy, etc.

With that out of the way, I'd think you could utilize the various hydrophone locations on the subs hull to determined depth. Sound radiates as a wave, so different parts of the wave front will contact the hull at different times (probably miliseconds apart, but enough to matter). For example if the hydrophone on the top of the hull receives a certain sound before one located on the side of the hull, the contact is above the vessel. Add in some fancy math, and you'd have a fair guess of the depth of a contact.

Basically what you're talking about is the principle that the WAA (Wide Aperature Array) on the Seawolf and Virginia class SSNs works off of to passively localize and range sonar contacts. The trouble with actually finding the depth though would be that you'd basically be doing TMA in a 3d field (accounting for vertical movement as well as horizontal) which I imagine would complicate things aboit.

This may just be ignorant oversight on my part, but I don't think that a huge emphasis goes into depth finding other than above or below the layer. Again this is just an assumption but I'm thinking that the detection zone on most of these modern weapons (Mk 48 ect.) would be wide enough that as long as you're in the right neighbor hood (above or below the layer) its not going to matter enough to really take into account.

[PL_Harpoon]

Actually in the game that's precisely what I do. Just pop in to see if he's above the layer and then return to sonar view.

[Hellguard3]

As someone who has never used a sonar device at a depth other than the surface, i know there are concievable ways for a computer program to quickly give a bearing, speed and relative depth. Obviously the closer the contact is and the more sensitive your equipment is the quick and more accurate this becomes.

Think of it this way. Your course, speed, depth, and location are being fed into a computer so it takes all of these into account in its computations. When you "pick up" a contact at say bearing 095 with broad spectrum sonar. You then ping again but this time you narrow your listening scope from 180 to 125 degrees vertical +and - 3 degrees horizontal to accomodate his possible movements. You can quickly narrow down his location tightening your angular "net", while keeping him centered in your sonar bearing.when you tighten and dont recieve a response ping you know hes either at the top or bottom of the net, so you just check both the top and bottom and where you get your ping. Wala!.

Now with all these pings and points of data you should easily have his Speed, Course, relative depth(which gives you his true depth based on your depth) and gives you a nice solution to go from.

Now if hes an enemy sub pinging a ton is giving away your position, but no fear! Using directional hydrophones (only 2 needed) its possible to triangulate his position.
Each phone when sensitive down to 1/2 to 1 degree can give you a bearing and elevation. Leaving you to fill in the trigonometric details with computers (even an analogue comp could do this job!)

If we were talking ww2 tech then yes it would be near impossible, but all you need is an elevation capabilities on your hydrophones and you could do this with 1 hydrophone by taking multiple readings over time. Similar to the "hydrophone only" course speed and bearing solution for surface ships. Except in 3 dimensions.

[suitednate]

Great discussion! Great input from everyone!