[REL] Tutorial for tracking with sonar

[jerm138]

I created a new tutorial on tracking and intercepting ships using hydrophone readings.

The concepts are not my own, but I thought it would be helpful to have a clear and concise tutorial on using this technique, and the theory behind it.

You can download the tutorial here

If you see any mistakes or have a difficult time understanding it, please let me know so I can fix it.

[I'm goin' down]

this looks like something I read on the MoBo tutorial. Is it?

[jerm138]

I'm not sure. I don't know what the MoBo tutorial is.

I've seen a couple tutorials on this method before, but none that really described the nuts and bolts of why it works.

I think that understanding the theory behind a technique helps you master it.

But that might just be because I'm a nuke.

[I'm goin' down]

It is an maneuvering board program by aaronblood and has its own forum. It is a masterpiece of work on intercepting ships. It is based on real life manuevering boards used on subs. You can used advanced intercept techniques with MoBo and the tutorial discusses something similar to your post. It is worth visiting the MoBo forum and getting familiar with it. The tutrial is almost as good as the program, which is amazing.

[razark]

Originally Posted by jerm138

I've seen a couple tutorials on this method before, but none that really described the nuts and bolts of why it works.

I think that understanding the theory behind a technique helps you master it.

I saw a video on this technique just recently. You tutorial helped me better understand how to do it, and exactly why it works. Thank you.

[virtualpender]

This is really handy. Thanks for putting this out. I hope it will be added to the Targeting Tutorial sticky mod.

[jerm138]

I'm glad it helped.

That'd be cool if it could get on a sticky. I'd be semi-famous!

[Pisces]

Superb!!! It looks very much like what Nefelodamon does in his hydrophone tutorial (video) that he posted in the Sh3 section.

http://www.subsim.com/radioroom/showthread.php?t=154461

http://www.filefront.com/14186971/Hy...on.part01.rar/



Jerm138: Excellently clear and step-by-step tutorial. Just like I would use the drawing tools. Well done!

[-Danse-]

Very neat and concise. You've really broken it down and made it bare-bones simple.

The illustrations help a great deal, and the transition from theory to in-game use of tools is considerate.

Thanks!

[ETR3(SS)]

Someone tell the FToW that if sonars data is screwy it's because there an Electrician at Broadband.

[XLjedi]

For most of your illustrations, the logic appears correct. I particularly liked the drawing with the two triangles. That's a nice illustration.

I think you'll find however, that if you attempt this while moving, your own motion will skew the plotted ships course. You'd be plotting the DRM (direction of relative motion) rather than the TC (true course). You may indeed even be able to triangulate on a location, but you won't have the correct track unless you do the vector addition and adjust for your OwnShips movement.

Most of your illustrations are related to stationary observations and those are all correct.... but the one where OwnShip is moving and speeding up and slowing down for instance, will only give you a DRM line (I think ). ...and it may even be OK if you just happen to be on a perfect parrallel path (as you chose to draw it).

I even think that example where you're showing OwnShip stearing an irregular course might only yield a DRM. The irregular course has an underlying motion vector that (I think) would need to be added to the plotted DRM. I could be wrong on this one... not 100% sure. Anyone can feel free to call me a doofus on this one, I haven't tested it.

(yeah I tend to appear when my name gets mentioned)

[jerm138]

Someone tell the FToW that if sonars data is screwy it's because there an Electrician at Broadband.

And this whole time you thought us nukes didn't know what was going on when we were up there.

Aaronblood,
This method works while you are moving (I've tested it). Even if you're speeding up and slowing down. The key is finding the course and range where all segments between regular-interval readings are the same distance. It doesn't matter where the "listener" is, if you find that line, you find the target.
I vaguely remember using this method on the real boat using a zig-zag pattern to pinpoint a contact's course, speed, range, and location.
One of the guys I currently work with was a sub officer, and he went over all of this stuff with me and confirmed that this is how they did it (in the 70's, anyhow.)

You're not plotting DRM because you're taking "snapshots" at regular intervals. At each snapshot, the enemy MUST be somewhere along that line, regardless of where the line begins (OwnShip location). Once you create a series of lines, it's just a matter of finding the right intersecting line (enemy course/range) that yields equidistant segments.

Below is an example of the speed up/slow down method. First is an image of the readings, second is the solution. Based on the readings, there is only one possible course and range where all segments are equal, even though my ship is moving on a different course and changing speeds the entire time.



But... if you can show how those methods won't work, I'd like to hear them so that I can change my tutorial accordingly. I don't want to put out bad info. You might be saying something that my dense nuke head just isn't getting

[Armistead]

Originally Posted by I'm goin' down

It is an maneuvering board program by aaronblood and has its own forum. It is a masterpiece of work on intercepting ships. It is based on real life manuevering boards used on subs. You can used advanced intercept techniques with MoBo and the tutorial discusses something similar to your post. It is worth visiting the MoBo forum and getting familiar with it. The tutrial is almost as good as the program, which is amazing.

Yep, that it is....

[XLjedi]

I believe you...

I never really thought about speeding up and slowing down before. So I guess it's OK as long as you don't maintain a constant speed then, correct?

[jerm138]

I've been thinking about this (probably too much) and I realized that you were partially correct in your original post, Aaronblood...

The concept I presented is still correct: The intersecting line that produces equidistant segments will give away the ship's course (and range if you have enough data) BUT .... (and here's the part where you were correct) the way you find that line will not be the same as if you're sitting still. You can't just move the first reading over then draw intersecting lines... it's more complicated than that for dynamic data.

I have to look into it further to see if there's a way to find that magical line with equal segments with data taken while you're moving.

Thanks for second-guessing me on it and making me think about it more. Back to the drawing board...