[REL] Tutorial for tracking with sonar

[jerm138]

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

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 (http://ricojansen.nl/downloads/Sonar_Tracking.pdf)

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]

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! :D

[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/Hydrophone.Interception.Tutorial.by.Nefelodamon.pa rt01.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.:har:

[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 :03:). ...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.

http://i166.photobucket.com/albums/u119/jerm138/course.jpg

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 :O:

[Armistead]

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... :yeah::ping:

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. :yeah: Back to the drawing board...

[XLjedi]

Actually I dunno... :hmmm:

(funny how we're arguing on behalf of each other now :03:)

After I typed that response (early this morning) it dawned on me that I was thinking in reference to a relative motion plot on a maneuvering board where all lines would radiate from the center.

In your case, you're plotting bearings on a DRT (dead reckoning tracer). The inherent motion I was thinking about I believe is accounted for in your update of OwnShip's position. Your plot looks more like the TMA lines in Dr.Sids Least Squares TMA solution example rather than one of my relative motion examples.

In MoBo there is a TMA tool that will do the measuring between the lines to help determine the target TC. Would you mind if I worked up an example or two on MoBo? ...for the benefit of those who like to use it. Of course, it would be even better if I could enlist you to do it for me. :D

Your example and Dr.Sid's original examples are both currently not represented with tutorials in MoBo. However, since MoBo is both a DRT and a Maneuvering Board, it is perfectly capable of handling the technique.

Incidentally, what graphics program are you currently using to create your tutorial images?

[jerm138]

I've never used MoBo, so I'm not sure I'd be much help there. I didn't even know it existed until this thread.

If you could come up with a way to prove or disprove this method, that'd be great.

I know the part about an intersecting line with equidistant segments is correct. The only part that would really need tested is the method for finding said line when OwnShip is not stationary.

For my tutorial images, I'm just using PowerPoint and exporting to .pdf. PowerPoint is an excellent vector drawing tool if you know how to use it. I'm a vector-art fanboy... raster doesn't cut it for me. I've tinkered with powerpoint for many years and I've made some pretty complex images with it. I even used it to re-make Cap'n Scurvy's AoB circular slide rule. I posted pictures of it here. (http://www.subsim.com/radioroom/showpost.php?p=1242903&postcount=28) It comes in pretty handy.

[XLjedi]

I don't think it needs further proving or disproving... However, I could easily prove that a two-legged series of equidistant observations while moving will yield a correct solution for true course.

I need to review Dr.Sid's logic now. There was a time when I was considering adding a least-squares TMA tool to MoBo, and I just haven't gotten around to it. I think Sid's least-squares method didn't even require that the observations be spaced at equivalent time intervals. On the one hand, that's pretty cool, on the other hand, purests might argue that the method would require more sophisticated computing power than may have been available at the time.

Your example strikes a nice balance in that it appears to be a valid TMA solution using methods that could have been employed with the technology available to tracking parties of the WWII era.

If you like, I can post a single MoBo image that will simply prove the concept works. If there is any interest from people wanting to know how I did it, I can follow up later or perhaps on another thread with more detailed MoBo instructions.

[XLjedi]

PowerPoint?

The only vector drawing tools I see in PowerPoint are the same lame autoshape and drawing tools that are available in Excel.

Are you saying you used those tools to create that AoB dial? :06:

[jerm138]

All I'm looking to do now is to find that "magic line" using the conventional in-game tools.

I racked my brain with it all day at work. Knocking down some geometry cobwebs. I'll get it eventually.

Yes, my tutorial, and that AoB calculator were made in Powerpoint. They're the same drawing tools used in most MS Office programs. They're definitely not lame once you learn how to use them... I even used powerpoint when kicking around ideas for my next tattoo! (It's a cover-up for a Batman symbol)... but I think I'm going to scrap this one and go with a more photo-realistic approach.

http://i166.photobucket.com/albums/u119/jerm138/tat.jpg

[XLjedi]

I thought it would take only one pic, until I plotted this first one and it didn't happen to work so perfect.

http://xl-logic.com/mobo/tutorial_pics/TMA_DRT_20100128_01.png
In this case we see that a 30° course change away from the hydro bearings would produce a fairly decent representation of target heading but the distance in this case remains ambiguous.

http://xl-logic.com/mobo/tutorial_pics/TMA_DRT_20100128_02.png
Turning 30° into the hydro bearings produces a better result with a little more certainty on distance.

http://xl-logic.com/mobo/tutorial_pics/TMA_DRT_20100128_03.png
The best results are achieved with more aggressive turns into the hydro bearings that result in lattice-type contact bearing lines. Here we can see the TMA tracking tool lines up best when overlaying the true target track. Of course the only problem with this is that if you maneuver your sub until you get lattice bearings, you will most certainly be left in a poor position assuming the very slow submerged speed of WWII era subs. You may then be stuck doing a surface run end-around.

Do you want me to post one for constant OwnShip heading with increase-decrease speed?

[Pisces]

The technique Jerm described in his document IS actually a two legged manouvre, combining a 'imaginary' relative plot (without range) with a dead-reckoning tracer. First leg is with speed of 0 knots. You do not really need to be stationary, just creeping slow to keep depth is ok too if you are pointed along a bearing line. That messes it up in the least way. From this you get only target true course, and are able to predict the next series of equal-time bearings. (since you were stationary the target-course is also the 'direction of relative movement', DRM in nautical terms) Knowing where the 4th (imaginary) bearing line will point to from the stationary location, you can move to a different vantage-point and create a form of 'stereoscopic view'. You can also go on, skiping the moment of the 4th bearing, taking a bearing at the time of the 5th bearing line, just as long as the track intervals and bearinglines are progressed appropriately. It is perhaps even desireably. You'll want as much as possible a 90 degree angle (a good crossing) between the imaginary line from the stationary location and real bearing line from the displaced location. A small shift of position, or small angle between real and imaginary bearingline makes the range and speed measurement from the plot very unreliable.

If you were actually moving during the first leg you would need to make the same bearing fan drawing (originating from the same center), but translate (move parallel) the line resembling the target course to the head of your speedvector (that originates also from the same center). This translated line is actually the 'direction of relative motion' or DRM on a manouvering board. Put the oldest part of the line at the head of your speedvector. (use the circle tool for this as Jerm suggested in his document, you can drag the arrow anywhere when moving the center) Anything 'in the past' (whatever was before bearing 1) has no meaning in this drawing. The 'future side' (every moment after bearing 1) of the DRM line is actually a collection of all possible endpoints of the target's speedvector. Since you do not know what distance the target travelled during each interval, as range is still unknown, you can also not know yet which point on the DRM line the target speedvector points to. You can however make an estimate on the maximum speed and minimum speed of the target, and show those as speedcircles (like a ring with outer radius 12kts and inner radius 5kts). This should cut-off the DRM line at certain points, indicating the course it would have had at those speeds of the borders of the speedring.

To figure out a definate target course and speed if you moved during the first leg (I mean like cruise speed, 1kts to keep depth isn't that big of a deal), you need another leg, moving in such a way as to create a direction of relative movement that crosses nicely the old DRM. What course and speed is required on the 2nd leg is tricky to figure out beforehand. Use trial-and-error, or when in doubt simply turn parallel to the initial DRM, and move at the estimated/guessed target speed.

This is why I like this method of a stationary 1st leg. I allready get to know it's course. For the second leg I then cruise at the topspeed of the reported speed-class(slow, medium,fast, etc). No need for flank if you're going parallel. You'll probably stay at or more likely gain forward position even with a moderate speed. Once you get to figure out range and speed (from the 4th real bearing) you can start to draw a propper intercept drawing at leisure speed.

[-Danse-]

Played around with this the other night to a satisfying conclusion. For the first three bearings, I kept it simple and remained stationary, and then poured on flank speed to get a good cross-reference point for that predicted fourth bearing.

Because of the distances involved, which were huge, I knew I wasn't going to be exact, but it gave me direction, approximate distance (within half a K as it turned out), and what I thought would be approximate speed, but actually turned out to be bang on.

After setting a timed intercept to arrive early for caution's sake, I let him get closer, repeated the process, confirmed the heading, narrowed down the distance to an accurate level and confirmed his speed.

From there it was shockingly simple to work out AoB from his heading and set up the Hydrophone shot.

Fired two, hit with two, on a small 1600 tonne freighter at a distance of 1500m.

Must say, it's very satisfying to be able to hunt a target and tear its belly out without having to put eyes on target. (I did anyway for enemy/friendly confirmation. Didn't need any "Sorry sir!" moments.)

Found this tremendously useful, so thanks a bunch. While I'm on the subject, thanks Pisces for linking Nefelodamon's tutorial. Downloaded and watched that the other night also. Again, very informative, very useful.

Nearly caused me to sleep in for work because I simply "had" to finish watching it at 1am. :)

I guess my next step is to try it on the move against a faster target to see if I can track and achieve a good firing position.

Fun fun!

Thanks again guys.

[Hitman]

USS Buffalo (SSN-715) "Buffy Love"
E-Div 1999-2003

Says it all about why you are so good at doing these sound bearing only tracking, uh? :D

Nice tutorial, many thanks :yeah:

[jerm138]

@ Aaronblood:
Thanks for taking the time to do all that. It looks like the 30-degree course change has less accuracy because you're introducing a relatively minor change. I like how the 90-degree one turned out :yeah:

@ Pisces:
Thanks for the extra detail. It's definitely more than I knew about it.

@ Danse:
I'm glad it worked out so well for you. I've never tried a blindfolded shot, but maybe I'll try now.

@ Hitman:
Yes, we avoid fresh air as much as possible.:arrgh!:

[Diopos]

Tools, tools, tools ...
Better to have them than not!
I think that all of you interested in this kind of stuff will find the original (and official) US Navy Department Maneuvering Board Manual of 1941 (!!) an interesting read (and adaptable to SH4's map/navigation tools)

download it from here (http://www.archive.org/details/maneuveringboard00unit)

Solve your tracking problems the way our forefathers did!!! :up:

(check cases VIII to XI)

[jerm138]

Wow... excellent find, Diopos!

I spent a long time searching for something like this online.
I found the US Navy Botswain's Mate manuals at NHSA, but it was all about OwnShip plotting, not how to intercept enemies.

Thanks for the link!

[I'm goin' down]

I highly recommend proceeding to the MoBo form and downloading the MoBo tutoroial and program. They are both masterpieces. Professionally presented, easy to use, well explained, and in short, remarkable.

If I could only master celestial navigaton my life would be complete.

Big wave to aarronblood. (see, somebody did read your tutorial!)

[I'm goin' down]

Cap'n Scurvy's art work (I offered to pay him to build me one)? power point? Take a look at gutted Solution Solver!! (I can go to sleep now!)

Waves to Hitman!

[Diopos]

A more modern version of the Maneuvering Board Manual (1984) can be downloaded from here (http://gcaptain.com/maritime/tools/files/MoBoard.pdf)

[Hitman]

I think that all of you interested in these kind of stuff will find the original (and official) US Navy Department Maneuvering Board Manual of 1941 (!!) an interesting read (and adaptable to SH4's map/navigation tools)

WOW amazing find man, love it!! This should get into the sticky for resources :yeah:

[Pisces]

WOW amazing find man, love it!! This should get into the sticky for resources :yeah:How about lobbying with Neal to get a seperate section in the downloads department of this site. Also for for the whizwheel-thingies like you made and similar game-external thing. :up:

[XLjedi]

How about lobbying with Neal to get a seperate section in the downloads department of this site. Also for for the whizwheel-thingies like you made and similar game-external thing. :up:

I was told that's what the "Utilities" section is for...

[Pisces]

I was told that's what the "Utilities" section is for...I see, ...now. :oops:

[Platapus]

Thanks for posting this technique (Coughcoughstickycoughcough)

On paper, a tool called a 10 point divider could be used for this. The concept of a 10 point divider is that no matter how wide it is extended, each point still remains in the same proportion.

http://www.landfallnavigation.com/n1188.html For a picture of what I am talking about.

A proportional divider, which has only two points, could also be used, but a 10 point divider makes it a lot easier.

It would be awesome of some smart modder could introduce a 10 point divider (or any other number) in to the plotting tools in the game.

I *think* the game 688 attack sub had it (but it could have been Fast Attack, I get them confused sometime). So I know it is possible to code. Whether it can be coded in to SH3/4 is another story.

Your way of using the circle function is innovative and imaginative. Well done!

My only issue is trying to do these steps while the game is running. Remember I am not that smart.

Tools that will help the player implement these techniques in the game are what is needed when .. ahem.. newer versions of submarine simulators are being designed.

I will be trying your method of altering the speed of the submarine. That never occurred to me. It is counter intuitive. I have always tried NOT to alter my speed. :damn::damn: Thanks for setting me straight.

And much thanks for taking the time to put together a nice easy to follow PDF. :salute:

[jerm138]

Platapus,
Thanks for the compliments. I can't take credit for the ideas though... they're all from other people... I just took them all and organized them into one spot.

My only issue is trying to do these steps while the game is running.

When you go to the plot, you can pause the game and still use all the drawing tools. Some may say that this is "cheating" but I disagree since the Skipper wouldn't really be plotting anyway.

[XLjedi]

When you go to the plot, you can pause the game and still use all the drawing tools. Some may say that this is "cheating" but I disagree since the Skipper wouldn't really be plotting anyway.

Whether you're the captain or not, realtime is realtime. If you take off the captain hat for a moment and become the tracking party, you should be able to pull off the plots in realtime.

A fairer argument might be that because you have to use the limited drawing tools it takes longer than it would in realtime, therefore it's not so much cheating as leveling the playing field.

[jerm138]

Whether you're the captain or not, realtime is realtime. If you take off the captain hat for a moment and become the tracking party, you should be able to pull off the plots in realtime.

When you become the tracking party and stay in real-time, who is the captain? By pausing while plotting, you're making it possible to play 2 roles simultaneously, instead of having the captain "disappear" for a few minutes.

It's all a matter of personal preference, though.

[I'm goin' down]

Radarman: Enemy contact, captain. Sounds like a BB.

I'm goin' down (with captain's hat on backwards): get MoBo out and give me course, bearng, and range. We're goin' to sink that sucker...Yea!

I'm goin' down (doffs captain's hat, and dons MoBo hat): 10 degrees, 190 degrees, 3,000 yds.

I'm goin' down: (discards MoBo hat, and is now hatless): where the hell is my captain's hat.

Ensign: The mascot ran off with it.

I'm goin' down (still hatless): The Yamato is getting away, damn it. We can't fire torpedoes until I am wearing the Captain's hat.

Radarman: Sound contact lost sir.

I'm goin' down: @!%#&*

[XLjedi]

When you become the tracking party and stay in real-time, who is the captain? By pausing while plotting, you're making it possible to play 2 roles simultaneously, instead of having the captain "disappear" for a few minutes.

It's all a matter of personal preference, though.

...and what duties would the captain be performing in this simulation in the meantime? Not much. Maybe ordering one or two course changes?
You're at depth, the captain is basically looking over the shoulder of the tracking party.

;)

[jerm138]

...and what duties would the captain be performing in this simulation in the meantime?

Time compressing!! :haha:

[Soundman]

This is outstanding, very informative and well explained. :up:

It's given me a new insight on using sonar with SH4. What amazes me most, is that while viewing this, it occured to me that the theory is no different than using the TMA analysis in modern sims, such as "Janes 688i" or "Dangerous Waters" where we align the arrow and dots to arrive at the most probable solution. :o The only difference being that in SH4 we do the plotting on the map ourselves, whereas with the modern sims the plotting is already done for us (and of course better and more sensors). I just never visualised the TMA plot in Dangerous Waters as a "map plot". I just never made the connection, but in reality it's the same thing, it just looks different! :yep:

Thanks for your efforts. You know.....I gotta say.... This community is fortunate to have such smart people within these forums. Certainly above average intelligence ! :salute:

[Pisces]

This is outstanding, very informative and well explained. :up:

It's given me a new insight on using sonar with SH4. What amazes me most, is that while viewing this, it occured to me that the theory is no different than using the TMA analysis in modern sims, such as "Janes 688i" or "Dangerous Waters" where we align the arrow and dots to arrive at the most probable solution. :o The only difference being that in SH4 we do the plotting on the map ourselves, whereas with the modern sims the plotting is already done for us (and of course better and more sensors). I just never visualised the TMA plot in Dangerous Waters as a "map plot". I just never made the connection, but in reality it's the same thing, it just looks different! :yep:

Thanks for your efforts. You know.....I gotta say.... This community is fortunate to have such smart people within these forums. Certainly above average intelligence ! :salute:There is still an important difference with the procedure shown in the document of the first message. In that document, for it to work, all first 4 bearinglines (3 real plus 1 imaginary) need to be taken from the same position, ownship should be nearly motionless. Whereas in 688i and DW and Subcommand the lines are plotted as ownship moves. The document is a clearly defined geometrical procedure to get the correct course and speed. But the TMA station in 688i, SC and DW is a bit more trial and error involved to get the dots aligned.

[rokoeh]

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

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 (http://www.filefront.com/15434459/Sonar_Tracking.pdf/) (683k .pdf on FileFront)

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


So guys... The download link its broken... Can I download this anywhere else?

[Harald_Lange]

So guys... The download link its broken... Can I download this anywhere else?


Second that! Any links guys?

[jerm138]

Yeah... Re-up it OP!


Oh... wait a minute...


Well, this is embarrassing. I just started re-learning everything since I stopped playing about 3 years ago. I vaguely remembered this tutorial but unfortunately the original files are long gone. I really HOPE somebody here has a copy and can re-up it.

[Pisces]

Fixed!

http://ricojansen.nl/downloads/Sonar_Tracking.pdf

[in_vino_vomitus]

Fixed!

http://ricojansen.nl/downloads/Sonar_Tracking.pdf


Nice one :)

[jerm138]

You da man, Pisces!!

Thanks!! :up:
Now I get to see if I'm as good of a teacher as I was hoping, since I have to learn from material that I barely even remember making. :know:

I see the address is .nl
Are you in the Netherlands? I was just there a couple weeks ago. I LOVED it!

I'm currently working on another tutorial for intercepting ships. Again, it's all information that I got from others, it's just assembled using simple illustrations like this tutorial.

[Pisces]

...

I see the address is .nl
Are you in the Netherlands? I was just there a couple weeks ago. I LOVED it!

...Yup, Check my Kriegsmarine gridlocation on the left. ;)

[Captain Diver]

Awesome job! thanks that helps so much. I downloaded the pdf. but there is only 24pgs. I am assuming that those are all the pages correct.? However I found this course quite informative.

[jerm138]

24 pages sounds about right (to anyone who hasn't read it, it's mostly illustrations, not 24 pages of text)

I wanted to keep it simple and clear. As I was going through it, I kept saying "ah, that makes sense!" so I guess I at least do a decent enough job of teaching myself.

[captcrane]

I'm always late to the party the link is dead . go figure

[jerm138]

I'm always late to the party the link is dead . go figureI updated link in the original post with the one that Pisces was kind enough to provide.

It should work now.

http://ricojansen.nl/downloads/Sonar_Tracking.pdf