View Full Version : [WIP] Hydrophone Tracker/Quick Plotter
[EDIT] If you want to test it out, read post #17 on page 2... then find the link in post #20.
Next version will have a friendlier UI and allow for you to do it while moving.
Nearing the completing of the latest tool slated for Solution Solver 2.0. I'm working on it as a standalone app, but the guts are contained in a custom control. Once it's done.. i can easily just drop it into Solution Solver 2.0's new tabbed interface.
Anyway, it's still a WIP... but it's cool as hell, provided you can feed it accurately. But then again, this is just a BVR estiamtion tool when you lack active sonar, and should never use it for TDC inputs. I tested it against Moboard's TMA plot, and i get the exact same results for ALOT less work. :D
http://img22.imageshack.us/img22/5273/overviewo.png
Just follow along with the pictures to see how it works. (Timing interval is the minutes you used between readings)
http://img231.imageshack.us/img231/4262/98132482.png
Note: some controls are disabled until you complete the step before.....
http://img715.imageshack.us/img715/9241/74588174.png
http://img186.imageshack.us/img186/2103/10598933.png
Note: Be sure to draw the predicted bearing on your in-game map before you move. You need it for triangulation.
http://img62.imageshack.us/img62/2060/94924861.png
Once you plot your triangulation line on the in-game map (the green one above).. you can see what range he is on the predicted bearing where your two lines intersect. You need that range to calculate his speed. Enter it and the dashed red esitamtion line will turn solid and move to the correct location.... the speed will then show, because now we now the distance he's been travelling between the sighting lines every 15 minutes. :)
Note: The green line is a photoshop.. it's not part of the program. You should be drawing that one on your in-game map.
Currently you have to be stopped when grabbing the first three readings.. once i get this finished and figure out how to even calculate it while moving, i''ll give it a whack. Still cleaning up some of the code and need to add a special case for when some of your 1st and last sighting lines are on oppostie sides of the 350/000 bearing line.
I've also expanded upon the crude position keeper "debug display" i left active in the 1st beta Solution solver 2.0.
It's now a full fledged feature and has it's own display, with auto zooming to keep both ships in view and a decent distance apart.
http://img143.imageshack.us/img143/4702/tacmap.png
urfisch
03-31-10, 04:09 AM
integrate apps ingame would be the greatest thing done so far!!! i think of a an enigma machine...and small ingame games, like chess, cards, etc. for getting the time passed...
difool2
03-31-10, 08:40 AM
TMA for a WWII sim-wow.
kylania
03-31-10, 09:34 AM
This looks amazing! I'd just started getting into this hydrophone hunting too. Unfortunately my first attempt was near a harbor so the in harbor patrols kept screwing me up. :)
TMA for a WWII sim-wow.
If you are hinting that this is unrealistic, then you sir are wrong.
It's done with alittle vector math, which you can do by hand by drawing with the in-game tools.
If you dont know how... then view this guide posted a long time ago:
http://www.subsim.com/radioroom/showthread.php?t=160817&highlight=tracking
The program uses roughly the same technique, but spares you from having to draw it out yourself. Think of it as telling your intercept officer the bearings and him plotting it for you.
Looks great. Another hydro-tracking tool. :yeah:
If you also allow for an option to set the sub's course while at the first listening position you could make a true-bearing plot instead of the relative plot now. Then you could also require the player to mark the old first listening location and the new listening location on the game map, have them just measure the (average) distance and course inbetween and feed that to your Solver. Then you'll have the full situation in a true bearing plot automatically. I preffer to do everything on the game map, but I guess alot of other users would find it tricky to compare this relative bearing plot against what they need to plot on the map (the little green line). But what you have sure makes things easier for them allready.
If you're interested, I scanned the pages from the bearings only TMA chapter from a copy of Naval Operations Analysis. It's focused on Ekelund ranging and Spiess TMA, the latter of which made my head explode.
link (http://www.filefront.com/15986641/Naval-Operations-Analysis---Bearings-Only-TMA.pdf/)
kylania
03-31-10, 02:00 PM
Wow, Jmr, that's some fantastic stuff. Orbitally over my head, but still fantastic. :)
If you're interested, I scanned the pages from the bearings only TMA chapter from a copy of Naval Operations Analysis. It's focused on Ekelund ranging and Spiess TMA, the latter of which made my head explode.
link (http://www.filefront.com/15986641/Naval-Operations-Analysis---Bearings-Only-TMA.pdf/)
Cool, will check it out later tonight when i have the time.
kylania
03-31-10, 10:15 PM
Ok, I totally need this now. :) Just tried my first map contacts off and found a single merchant. Took me an hour to figure out where he was, and I had to do the map drawing 3 times! heh 3rd time was the charm, but then it was foggy and I couldn't double check his speed before he was past me, so shot from the gut at 2500m out! One exploded early but the second one grazed his bow (guess the speed wrong...)
So please, if you need a beta tester, I'll help :)
It's just about ready, hopefully have it finished tonight (if not then tomorrow). Just have one more issue to sort out.
Anyway, I'll release it as a standalone for testing. Then when Solution Solver 2.0 is finished, it will be included as one of it's tool pages.
Finally solved my problem. Good grief.. that one had my mind going in an infinite loop. Was actually starting to get a headache from it.
Putting the finishing touches on it now. wont be long.
kylania
04-01-10, 12:02 AM
\o/
It's done. But it's too late for me to try it out in-game. I'm getting tired.
So....Kylania check your .pm box. Give it a workout and if it's performing ok i'll upload it to subsim for download tomorrow.
Ironing out the bugs I take it?
Actually no, its working as intended.
But im thinking of redisnging it after some input from kylania. .ie instead of inputting them into text boxes you draw them out, with little drag handles so you can move them around.
Also im going to add support for any number of sightings.. becase as it is right now, the accuracy depends entirely on how "correct" your 3 sightings are. Being 1 degree off can skew the results. So if instead you use 4 bearings, it will grab the course of the first 3 & last 3 and then average them out. If you add another one.. it will refine it even more etc.
I was getting pretty decent results from it (within 5 degree course), but i knew the tolerances and was carefully listening. Kylania on the other hand didn't realize this, and he didn't get the intended course.
If you are interested in using this initial test version.. i guess i can upload it as is.. but you just need to keep in mind that with only 3 bearings... theres not much fudge factor and it should only be used as an estimate.
My advice would be to open two instances of the app and take 4 bearings. Enter the first 3 in one window, and enter the last 3 in the other window, and compare the two courses.
Takeda Shingen
04-02-10, 09:48 AM
Moved to appropriate forum.
The Management
You mean, I don't need to check every hour again to see if it's finally available? :wah:
Call me a nerd or whatever, but somehow this TMA stuff got me hooked! :03::yeah:
Ok you can test it out:
http://www.subsim.com/radioroom/downloads.php?do=file&id=1699
Just keep in mind that im working on a more robust version. Both in the computed solution and UI friendliness.
Also: a few things have changed since the screenshots posted. The range scale at the top left is gone, the display is no longer zoomable with the mousewheel. The red line doesn't turn solid and move to its correct range once you input it. Displaying it at the correct range was a useless feature, and only forced you to zoom in and out. Instead the lines will scale to fit the bearing wheel.
kylania:
You might wanna redownload it, i made two small updates to it since your copy.
1. The lines are anti-aliased now.
2. The predicted bearing and estimated course readouts are not rounded anymore.
Dude, why the hell did you move the thread here?
It's not a mod.
Now you're going to have all sorts of people jumping in here thinking i made something to drop into their game.
One last tidbit.. you can do with the scope as well.
Just use a smaller interval due to the closer ranges.
It's useful for stalking prey at very long distance. Which leads me to the next question: will you support TMA while moving as well?
Started redisnging it.. got the drag handles drawing (though they dont drag yet hehe). Also made the middle area of the bearing wheel fainter. Bearing lines will be thinner as well (not shown).
http://img101.imageshack.us/img101/2674/wip1u.png
It's useful for stalking prey at very long distance. Which leads me to the next question: will you support TMA while moving as well?
Without a range for each bearing .. how would you convert the target's direction of relative of movement (DRM) to an actual course if you dont know it's relative speed?
I just dont see it happening from a static manuevering board type display.
Without a range for each bearing .. how would you convert the target's direction of relative of movement (DRM) to an actual course if you dont know it's relative speed?
I just dont see it happening from a static manuevering board type display.
Hmmm, I think what I had in mind was something along those lines (excuse the pun! :03:):
http://www.subsim.com/radioroom/showpost.php?p=1140250&postcount=2
Especially the last part about relative motion and speed and course vector to obtain true motion. Just with automatic calculation of the latter. I don't know if this is feasible, hence my question.
In that example he had to guess at what the range was to get an estimate of the targets speed on the reatlive track.
Without a "sonar ping" in a Uboat, how do you intend to get this range?
And like i said, without an estimate of the target's speed on the "relative track" you can't convert it to a true course and speed.
That's indeed a tricky one, as there is no course change in the example. But we have a cross bearing, thus getting more or less precise results. Just relative in this case. Then do the vector calculation using initial (!) OS speed and course and the end result target data.
Not sure if we are on the same page, though.
Ok let me get this straight to make sure we are thinking the same.
Lets say you are heading 30 degrees at 5kts.
You plot the three bearings on that static board and get a relative course.
But since you dont yet know the range, you have no way of knowing the relative speed of the target, and thus cannot do the vector cacluation to transform the relative course to a true course and speed.
So... you turn and triangulate the 4th bearing to get the range. Then input that on that board.
It can now caclulate the targets relative speed from that range... and using your heading and speed (which you didn't change when you turned away), it can compute the true course and speed.
did i get that right?
.ie You turn and or change speed to triangulate the predicted bearing... but you leave your original course and speed unchanged on the board?
kylania
04-02-10, 12:29 PM
One other thing I'd add is a GIANT PULSING LETTERS with trumpet fanfare saying "Draw bearing #4 on the map before you move!" :O:
I've so far forgotten to 4 out of 5 times.
Also, this thread has a nice PDF that explains a lot of the methods used here, including moving various speeds to get a course:
http://www.subsim.com/radioroom/showthread.php?t=160817
yea i already linked to that on the first page.
also, as per my last post... im not sure it would work. You would have to draw the predicted bearing in your future location (of your original course) on the map to triangulate it after you turn.
That was about 90% right! Except that we do change course and speed for triangulation, but but for relative/true conversion we still calculate with the course and speed we initially had when taking the readings (in this case 30°, 5 kts), as these are the ones that will matter. We're basically using old data for OS and fresh data for target. Just ignore course and speed of the final leg, as this just serves for obtaining the cross bearing! I will try to set up an example tonight. It should work already by utilizing Mobo for the final step. You can try this yourself if you like.
What im saying is that in order to "triangulate" the predicted bearing on the in-game map... you are going to have to draw it from where you will be in the "future" if you were to stay on course. .ie if you are doing 6kts and using 10minute intervals.. you'll hve to draw the predicted bearing from a point 300.8 meters in front of you before you turn.
then turn, triangulate it, and send the range back to the tool so it knows what the relative speed was for the first three sightings. then it can finally transform the targets relative course to a true course using your original course & speed before turning,.
how to make this process easier?
The idea behind this tool was to make it simple and quick. which is why its using a static display.
No wait, I think I know what the problem is: you think you do this while tracking the target! That's not necessary! Here is an example how it will work now, using Mobo for the final step (or use a pocket calculator):
1. track the target, triangulate, do what you usually do until you are completely finished! All data is now collected!
2. Don't touch it any more!
3. Fire up Mobo
4. Set up OS with (to stick to the example) 30° 5 kts (important!)
5. set up contact using the final data once you are completely finished: bearing, distance, relative course and speed!
6. Finally, use the subtract vector tool to convert target course and speed from relative to true! There!
You're right, it should be kept simple, but there is only one final step involved to convert from relative to true! ATM it's a bit more complicated because two different programs are utilized. But with your TMA tool it could be much easier. We would merely enter our initial OS data when we begin. That will be the only additional required step by the user. The program does the rest once all data has been collected! No need to fiddle with Mobo and vectors, then.
you dont need mobo to do the vector calculation.. you can just draw it.
And you dont need the bearing/distance.
All you need is the two vectors and their magnitude (direction and speed).
you dont need mobo to do the vector calculation... you can just draw it.
Of course! I figured this might be a simple way for proof of concept! And the concept is to add one more step for vector magic to make the tool even more versatile! And you want it simple and user friendly, right?! :03:
I still fail to see how you are triangulating the predicted bearing without taking the extra step of plotting it in-game where you "will be" given your speed and time intervals.
If you want to do it moving you need 2 sets of 3 bearings as you need to make a significant course and/or speed change in between to alter the relative motion. And both 'target courses' need to be translated to the head of your own speedvectors. Where they cross is the endpoint of the actual target course and speed vector.
Read here:
http://www.filefront.com/13598315/bearingsonly_TMA.pdf
Also, for better accuracy in course, just take longer periods between the bearings. Waiting for 4 degrees bearing change is really too short. I guess you could average it out like that (first three bearings and last three bearings out of a set of 4), but it still has a large margin of error which doesn't go away doing that. You think the bearing is exact when it is reported, but it could be a full degree of. So the difference between 2 bearings has a total margin of error of 2 degrees.But since this method depends on 2 bearing differences the margin of error doubles again. Compare the following bearing sets:
B1=11, B2=15, B3=22, which makes target course 177
(from the original post example)
B1=11.00, B2=15.99, B3=22.00, which makes target course 150
B1=11.99, B2=15.00, B3=22.99, which makes target course 186
186-150=36 degrees margin of error.
I'm not too happy about that!
Yes, that can utlimately happen if you rely on crew reports that are not taken when the bearing crosses the exact degree.
Now lets say you wait longer, like until bearing has moved 7 degrees:
B1=11, B2=18, B3=37, which makes target course 177.1 (our reference)
Then taking worst case margins of error:
B1=11, B2=18.99, B3=37.00, which makes target course 173
B1=11.99, B2=18, B3=37.99, which makes target course 182
182-173=9
Much better, and if you do the math (which I'll spare you) those 7 degrees only took 50% longer, so 22 an a halve minutes per interval.
reaper7
04-02-10, 01:30 PM
Very handy tool Gutted. Look forward to trying it out. :up:
The whole process remains the same! Mind you, I just add an additional step at the very end of the process: the conversion from relative to true! Whatever happens before that doesn't matter in this case!
Oh, and it doesn't matter if the sub moves at 1 knot or 10 during tracking! The data will always be relative! When you treat 1 knot as 0 knots, there will always be a error in the end result! So by doing the vector calculation for any speed above 0 kts should also increase the presicion! Another benefit. :D
Anyway, we can discuss this all day long and won't get anywhere if we don't try in in game.
@pisces
dude, that pdf example was priceless.
Next version of the tool will work beautifully. :D
Anyway, we can discuss this all day long and won't get anywhere if we don't try in in game.
The thing is.. unless i can picture what you're saying, it's futile. :DL
Then taking worst case margins of error:
B1=11, B2=18.99, B3=37.00, which makes target course 173
B1=11.99, B2=18, B3=37.99, which makes target course 182
182-173=9
Much better, and if you do the math (which I'll spare you) those 7 degrees only took 50% longer, so 22 an a halve minutes per interval.
So do you think im wasing my time adding support for more than 3 bearings and averaging them?
in other words... we should just use bigger intervals between sightings intead?
The thing is.. unless i can picture what you're saying, it's futile. :DL
He he! It's about dinner time, so one more try before I'm gone! Let's assume that your boat is creeping along with 2 kts while you track that lone merchant far away. You collect bearings, then make the final triangulation, do the drawing stuff on the in-game map, etc. Then you're done! Or are you? You sit there, about to plan your intercept course. But you hestitate, raising your eyebrows and wonder how precise your calculation might be! While you sit there, still scratching your head, you realize that the result may be skewed due to OS movement. It was very slow, but still.
Then you wonder how you can correct for this error! Ahhh, there is the answer: you need to do this weird vector calculation stuff to un-skew your result! And so you do and when done you are happy, because you now have a much more precise result than before!
And then it dawns on you: it doesn't matter whether you were moving with 2 kts or 15 kts! The calculation for error correction remains the same! So you figure out that you don't need to sit still, you can just go at any speed, and then just correct for the error afterwards!
Now you are happy because you are getting better results than before and add this function to your program!
LOL! Just kidding, but I couldn't resist! :har:
Hope this helps!
Read here:
http://www.filefront.com/13598315/bearingsonly_TMA.pdf
I fully read it, and i understand it all the way to the last step, and then i can't follow.
R2-M is the relative speed on the second set of observations (28.4kts). Z-Y is 2 hours total.. so the distance of Z-Y is 56.8 miles.
So.. uhh.. what determines how far along Z-Y that A is being placed to find B?
He he! It's about dinner time, so one more try before I'm gone! Let's assume that your boat is creeping along with 2 kts while you track that lone merchant far away. You collect bearings, then make the final triangulation, do the drawing stuff on the in-game map, etc. Then you're done!
you still dont get it :)
read the part in bold again.
If you are moving, you need to figure out where you will be on the in-game map in the future and draw the predicted bearing from THAT location. otherwise your triangulation will be wrong.
Anyway, the pdf pisces posted is the direciton im probbly gonna head with this.
input your 1st course and speed... grab three bearings.
Input your second course and speed... grab another three bearings.
It then tells you the targets true course and speed.. .and the distance along the last bearing he was.
So all you'll need to do is draw out the last bearing from you to the distance it gives you... then move the other end of it in the direction the target is going and you're good to go.
you still dont get it :)
read the part in bold again.
If you are moving, you need to figure out where you will be on the in-game map in the future and draw the predicted bearing from THAT location. otherwise your triangulation will be wrong.
Anyway, the pdf pisces posted is the direciton im probbly gonna head with this.
input your 1st course and speed... grab three bearings.
Input your second course and speed... grab another three bearings.
It then tells you the targets true course and speed.. .and the distance along the last bearing he was.
So all you'll need to do is draw out the last bearing from you to the distance it gives you... then move the other end of it in the direction the target is going and you're good to go.
And while I wrote this I've burned my dinner! YIKES!!!
Hey don't get me wrong, I'm not saying that you are wrong and I am right! I'm just trying to get a point across, which turned out to be more difficult than I have expected! :haha:
To make a long story short: you say this doesn't work as this will introduce a new error (position), while I say it's all a matter of conversion! Can we at least agree on that?
Be that as it may, Pisces has made this debate obsolete anyway. :rock:
Man, I had a good laugh! :yeah:
:D
It's all good man, it's just we're looking at two different things. If you can tell me how you're going to triangulate it without a hassle im all ears.
:D
It's all good man, it's just we're looking at two different things. If you can tell me how you're going to triangulate it without a hassle im all ears.
Dunno! I was so busy typing that I couldn't test it! :haha:
Ok i figured out a way to do step (11) in that pdf mathematically without using scales to figure out how far along to draw A line Z-Y.
Instead of drawing A-B where it shows on that moboard... you instead draw it with A centered at P2.
then you take the vector length of Z-P2 divided by the vector length of Ownship-B.... to get a ratio to multiply the relative distance to get the actual distance.
So do you think im wasing my time adding support for more than 3 bearings and averaging them?
in other words... we should just use bigger intervals between sightings intead?Yes, small bearing changes/short intervals only make bad results. And many bad results do not average to a good one.
It's difficult to explain why. Your measurement accuracy cannot be better than 1 degree if you let your crew call out the degrees. Maybe better than 1 degree if you use the periscope bearing scale. But much worse if you have to listen for the sounds on the hydrophone yourself. Anyway, 1 degree off in for example a 4 degrees inerval means the target track during it is upto about 25% wrong in length. But 1 degree after a change of 10 degrees is only 10% wrong. 1 in 50 is 2%. The issue is called 'granularity'. Alot of bearing measurements over short intervals only means more work. The data is then all of the same bad quality. Longer intervals means less measurements and drawing work, and better accuracy. Trust me, patience pays of in reliability.
You could reuse old bearings by doubling the time interval. You keep bearing 1 as the baseline. Old bearing 2 is discarded. Old bearing 3 becomes new bearing 2, while the new bearing 3 is measured after the 4th short intervals. This way you get an early estimate on course and you may decide to let it go if if is moving away. But still get the luxury of better data.
If possible try to choose the interval so that the final bearing (3rd) to be when the target would show an AOB of 90 degrees, or when he would be the closest range from the listening location. That way the 4th bearing will get the best crossing when you move parallel to the target.
you still dont get it :)
read the part in bold again.
If you are moving, you need to figure out where you will be on the in-game map in the future and draw the predicted bearing from THAT location. otherwise your triangulation will be wrong.This is a bit of a problem indeed if you need to submerge to listen and be on the move surfaced. It's tricky to adhere to that average speed between taking the bearings. Best is to just flank it
on the surface to somewhere along a course some certain distance away. Then wait there wasting time to make the average speed match up. When the 2nd bearing has been measures, surface like a madman and flank/sprint another such distance ahead to be there early. Again wait there submerged to make the average speed match to whatever you have chosen to use in the plot.
Yeah, who said a navigator's life is easy. :88)
This 2-leg technique is better suited for modern subgames like Subcommand/Dangerous Waters/688i since they are submerged the whole time and can go faster than WW2 subs. The ranges in those are usually alot further though, meaning slower bearing changes. However the crappy drawing tools on the map prevent me from doing it in those games. And the TMA station there spoils alot.
In SH3/4 (5 if I ever buy it) I'll do the 3-bearing-then-sprint technique as shown in the images in the beginning of this thread. Sometimes I do the 2-leg technique using the periscope at extreme visual range. Still trying to perfect my skill in these methods though. Knowing is something else than doing in the heat of battle.
kylania
04-02-10, 05:31 PM
Yes, small bearing changes/short intervals only make bad results. And many bad results do not average to a good one.
It's difficult to explain why. Your measurement accuracy cannot be better than 1 degree if you let your crew call out the degrees. Maybe better than 1 degree if you use the periscope bearing scale. But much worse if you have to listen for the sounds on the hydrophone yourself.
That's the problem I ran into. I made a test mission with a ship heading course 118 at 8kts. The first time I ran the numbers I used exactly 15 minute intervals and used the "Report nearest contact".
The numbers he gave me were 333, 340 and 347. This ended up with a target course of 70 degrees! No where near the true course. I asked gutted about it and he pointed out that using 334, 340, 347, a ONE degree difference in one of three bearings and you ended up with 104 degree course. Still wrong, but at least in the right general direction.
Not sure how to get around this really.
Yes, small bearing changes/short intervals only make bad results. And many bad results do not average to a good one.
[EDIT] However, some people can't stand it sitting still and feel they must do something in that time. Something may be said for that. Might be good for them to achieve Zen-state. ;)
Okay, tested my method in SH3 sub school, torp training! This is what I did: 3 bearings, 10 minute marks, enter them into the Hydrophone tracker. From the last position, at 20 min, the point where I took the last regular reading, I entered the bearing given to me by HT. Then I sprinted to a new location for triangulation. Then I went on as usual, took the new bearing for triangulation, measured the distance that I entered into HT. Now I get some results.
I have tried this several times now! With and without moving. Without moving always were some degrees off the mark, speed was a bit off, too.
With moving the results I got from HT were strange at first glance. To be on the safe side, I entered them into Mobo, using the method I have explained in another post above.
What can I say? 3 bearings plus 1 triangulation, and the resulting target course and speed were always less than 1 degree off, speed also very close to the real thing! Much better than just standing still!
I have to admit that I was a bit surprised myself. I don't understand the math behind it. In fact, I'm a doofus at math. But for whatever reason it seems to work! The precision seems to be somewhat dependend on the direction I take for the triangulation.
This is all certainly worth further investigation! :yeah:
Could anyone else please try this method and report the results?
That's the problem I ran into. I made a test mission with a ship heading course 118 at 8kts. The first time I ran the numbers I used exactly 15 minute intervals and used the "Report nearest contact".
The numbers he gave me were 333, 340 and 347. This ended up with a target course of 70 degrees! No where near the true course. I asked gutted about it and he pointed out that using 334, 340, 347, a ONE degree difference in one of three bearings and you ended up with 104 degree course. Still wrong, but at least in the right general direction.
Not sure how to get around this really.The numbers 333, 340 and 347 indicate that bearing 2 is about the bearing that shows an AOB of 90 degrees. Since bearing 1 and bearing 3 are equal degrees from the 2nd one.
Perhaps it's easiest to see if you make this 3 bearing AOB tool (shameless plug :know: ) It does the same thing as doing the 3 bearing drawing in Gutted's tool, (:yep: has to be) except for calculating the angle of and distance to bearing 4. It's just an AOB tool.
http://www.subsim.com/radioroom/showthread.php?t=147719
Notice how the smaller bearing differences are wider apart(i.e. 5 to 6 on outside scale), compared to the larger bearing differences (i.e. 20 to 21 on the same outside scale). This means the top disk needs to turn less if you want to see how big an effect one degree error has on long interval bearing changes.
Ok after a bit of hacking on the test version of the tracker...
I get this when using the example in the PDF... cant figure out why it's off:
http://img30.imageshack.us/img30/6855/wtfmobo.png
Are we sure the solution in the PDF is correct? Mine was done mathematically with floating point precision and not drawn by hand.
Note: the above UI will not be the final version.. its just the previous version hacked to work with 2 groups of bearings.
If anyone wants to try out the moving version:
http://www.subsim.com/radioroom/downloads.php?do=file&id=1704
Be warned its had very little testing, and i'm not yet certain if the results are correct.
It's a beta version that needs testing.
And yes i know the UI is a bit strict (.ie forcing you to start over if you screw up), but thats because this is a very early version and im forcing the user to do things correctly.
Once its working as intended i'll free up the UI and make it more friendly by accounting for changes in data.
Just tried the moving version on a target that was doing 90 degrees at 9kts.
I came up with 108 degrees at 8kts using 10 minute intervals. Not bad accuracy for such short time span.
Only problem? It took so long to freaking do two sets that he was already in view when i started doing the second set LOL. I started using the scope for the bearings.
Will have to not use the moving method when the target starts so close.
Now that i think about it.. im not even sure how practical the 2-leg moving method is given the short hydrophone ranges on a u-boat.
It's rather pointless to be listening that long.
If you look at that example in the pdf the target was like 68nm away.. thats like 125km. Much more practical.
Now scale that down to U-boat a hydrophone of like 20km listening distance. You run for 30 minutes listenging at 3kts for a target thats doing 11kts... and he's already travelled almost half the distance (8km), while you've traveled nearly 3km... and thats just the first leg !!!
It seems much more practical to sit stationary and listen for like 20-30 minutes and see what he's doing before you start moving. If he's closing it wont be long before you get contact anyway. You have about enough time to run to a triangulation point to get his true distance and speed then setup for an intercept.
Yup, manual TMA is a bit of a pain in the ass. I tried it awhile back as detailed in this thread (http://www.subsim.com/radioroom/showthread.php?t=110619) and through examples with Mobo, it ultimately just wasn't worth the time and effort. The concept, however, is really cool - being able to ascertain a target's range, course, and speed through the use of passive sonar. Of course it all goes out the window if the target alters his speed and course :haha: I just leave the TMA stuff for the boats in Dangerous Waters and stick to my whiz wheels and Mobo for intercepting known contacts either reported by radio or spotted by my lookout crew.
Ok after a bit of hacking on the test version of the tracker...
I get this when using the example in the PDF... cant figure out why it's off:
http://img30.imageshack.us/img30/6855/wtfmobo.png
Are we sure the solution in the PDF is correct? Mine was done mathematically with floating point precision and not drawn by hand.
Note: the above UI will not be the final version.. its just the previous version hacked to work with 2 groups of bearings.I too think the results (target course and speed) in the pdf are a bit wrong in that chart. I get a target speed and course when drawing by hand (177-ish) that is much closer to 180 degrees like your tool. My drawing shows a speed of 10.5 kts. But the method itself works.
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