Pato's fixed bearing tool still in error?

Von Due · 04-05-16, 03:46 PM

As many of you will know, there is and has always been some issue with bearing tools and the nav map. Pato's tool, although being a must-have to many, me included, also suffered from it. One of the old MaGui mods I still had on my HDD had a fixed image which I installed on the new WS MaGui installment of SH3/GWX3.

To my surprise it was still 0.5 degrees off:
I had map contacts enabled and had the sound guy track a target. Tracking lines moving clockwise, he would not report the new bearing until the tracking line hit the degree marks spot on BUT

This has always, to my knowledge been a real issue, that there is a consistent rounding error in SH3 that has nothing to do with any plotting tool.
Set the depth to 25 meters and the boat will most likely stop at 24.5 m. Come up from below and the boat will level at 25.5m.
Turn clockwise to 90*. The boat will stop turning at 89.5*. Counter clockwise the boat will stop turning at 90.5*. To get to 90* dead on I need to fiddle with the rudder manually to set the heading.

I assume therefor that the sound guy is guilty of the same, rounding off reporting 105* when the tracking crosses nearest half.

Therefor I assume that Pato's bearing tool would be correct if the tracking line was at nearest half when the sound guy reports the new bearing, NOT right on the degree mark.

EDIT: Just to clarify. I know the worst was that the old graphical error was inconsistent so that eastwards had greater error than west but this I just saw here with Pato's being consistenly 0.5 off all the way reall caught me off guard.

Can someone chime in here and fill me in on how this is supposed to work now after these fixes of Pato's and probably other fixes as well.

No wonder my 4 point bearing showed USS Enterprise at low altitude full throttle. Off 0.5 degrees when the sound guy already has given me a full degree possible error really add up to bizarre results.

Pisces · 04-06-16, 03:39 AM

I'd say that if the Uboat is spawned into the world with an exact 0 degrees N,E,S or W heading and the bearing-grid aligns perfectly to the grid on the map in the deeper zoomlevels then it is ok.

I do think that one should NOT rely on the number bearings reported by the crew in the text box, or pronounced as audio. There are delays involved and indeed seems to suffer from roundoff errors.

If you are not sure about the boat heading when spawning in a career you can check it by making a custom scenario and see how that aligns.

If the grid aligns good to the horizontal and vertical coordinates when opened in a graphical editor then it should be ok. The original bearing grid could have been place rotated on the scanner plate. Not every one is painstaking in correcting it's orientation. The scan may even be warped or skewed (not equally wide horizontally as vertically).

[edit] Even relying on the waypoint marker to get to a perfect heading (when the line is straigh) is questionable. When the heading is achieved or close enough the helmsman goes on a break until you re-command him to a new heading. It's not perfect.

Von Due · 04-06-16, 07:27 AM

For true course and navigation in game, what I do is I mark the tip of the sub icon, travel for a bit then mark again. That gives me the course I use and by comparing to the compass also any wind correction or other drift.

This whole thing came up as I was practicing hydrophone only tracking, to use with the 4 bearing method. Up until now the 4 bearing method is only accurate if I have the tracking bearing lines enabled. Without them, and because I could be as much as 1.5* off when plotting, the results more often than not resulted in absurdities.

One can plot various solutions to the 4 bearing method using min and max lines for bearing so say if bearing 1 is 134* then I'd draw up 133.5*, 134* and 134.5*, same for the other bearings. That gives 27 different outcomes for 3 bearings and 81 outcomes for the 4. and final bearing. It would be not only result in a map utterly unreadable but it would be pretty pointless as you still would have to guess which one to go for.

Anyway, what may work for practical purposes with no map updates and when using Pato's tool is to allow 134* to be anything from 134* sharp to just less of 135*- Average that to 134.5* on Pato's tool and use those bearings.

A more advanced method includes keeping track of when the sound guy reports a new bearing using a clock mod with a seconds hand.

Let's say I pick up the sound at 11:55:00 at a bearing > 135* and I'll use time intervals of 5 minutes.

I spend the first 5 minutes trying to work out how often the bearing changes and if it's a CW change or CCW change. Let's say this is a CCW change at 1 minute intervals, roughly.

At 12:00:00 I plot down the last known bearing. Now if the bearing changed once roughly every 1 minute and the last report was at 11:59:45 then I will draw the line at 134.75* (134.25 if the change was CW). If the last report was at 11:59:30 then I'd draw it dab in the middle at 134.5* and so on and so forth.

Now it is crucial that the sound guy and Pato both agree on where a given bearing is for all bearings in any orientation. Any offset due to hardcoded f ups will throw this accuracy out of the game.

siege00 · 04-06-16, 09:47 AM

Regarding the compass variation: I wonder if they built magnetic variance into the game. There is a difference between map north and magnetic north and depending on where you are in the world, it could legitimately be .5°. It's entirely possible that the devs built that into the game, though it may be a stretch for me to even suggest it. If they did build it in or a minor facsimile of it, then that may explain a few things, though if it is built into the game, you'd figure they would've marked variation on the charts. Would be extremely cool if they did though. lol. It could've even been partially built into the game as features are trimmed for release and wasn't completely removed.

Just food for thought? Or a feature in a future sim.

Von Due · 04-06-16, 10:56 AM

I did consider the possibility of mag north vs true north. In FSX that is a constant headache as I prefer to fly far north. In this game however I am more than a bit reluctant to accept it. They couldn't give the nav officer a stopwatch but they built in mag north? On Planet Cylinder?

nocken · 04-06-16, 12:57 PM

THE MAGNETIC DIFFERENCE IN JUNE 1940 WAS 10 DEGRESS WEST. SO LETS SAY 350 DEGRESS IS TRUE NORTH, THEN 0 DEGRESS ON COMPASS IS ACTUALLY 10 DEGRESS. SO THE QUESTION IS. DO THE IN-GAME COMPASSES TAKE IN THE DIFFERENT MAGNETIC DIFFERENCE. OR DO WE HAVE TO COMPANSATE THAT 10-11 DEGRESS DIFFERENCE.?

Pisces · 04-06-16, 01:32 PM

The magnetic anomaly is of little importance in this game/simulation. The boats in those times made use of gyro-compasses which aligned themselves to the poles of earth rotation by precession. Mere mechanical disturbances nudging it around. Not at all by magnetic torque. So modelling it seems redundant. Aside from that, there are many bugs that they had better had put their time on squashing them.

If you want to reduce errors when working with the 4-bearing method then I suggest you increase the time interval to than a halve hour. Or whatever makes the bearing drift 5 degrees to begin with. Unless you use the periscope for bearings the bearing-error isn't likely to be much smaller than a degree.

Von Due · 04-07-16, 04:39 AM

To Nocken: Mag north is far more confusing than a fixed number like 10* west. Have a look at a map of the deviation lines for the entire planet for a given month/year and if that doesn't confuse you then I don't know what will.

As for the inaccuracies in bearing, yeah greater time intervals as suggested by Pisces would get me a long way but unfortunately it seems that is a luxury I can't always afford. Sometimes I need to get it all solved in less than 20 minutes leaving only a few minutes between readings.

Pisces · 04-07-16, 05:34 AM

Quote:

Originally Posted by Von Due

...

As for the inaccuracies in bearing, yeah greater time intervals as suggested by Pisces would get me a long way but unfortunately it seems that is a luxury I can't always afford. Sometimes I need to get it all solved in less than 20 minutes leaving only a few minutes between readings.

Why do you think all will be over in 20 minutes? Your hydrophone can listen to a radius of more than 30km. It takes a contact much more time to cross that. You'll have plenty of time before you really lose it. The lines on the map may fade out before that. But the equipment can still give bearings.

Von Due · 04-07-16, 06:10 AM

Quote:

Originally Posted by Pisces

Why do you think all will be over in 20 minutes? Your hydrophone can listen to a radius of more than 30km. It takes a contact much more time to cross that. You'll have plenty of time before you really lose it. The lines on the map may fade out before that. But the equipment can still give bearings.

Last patrol I played my sound guy first picked up the contact at great range, then lost contact (!!!) even though I could clearly hear it in the hydrophone room, until the target was between 12 and 15 km out moving at medium speed (ended up passing about 700m in front of me) leaving me very little time to do the reading. Weather was real bad and I was at 40m, then 20m then periscope depth, trying to get the sound guy to work for the team.

Pisces · 04-07-16, 02:05 PM

Well, you don't need to hurry the procedure just because it is near. You are not forced to attack then. That is when mistakes are made, when you let the target decide what you must do. Just continuing the procedure, letting it pass while taking the bearings, would have given you (more) accurate speed and course and mk1 eyeball confirmation on the calculated/plotted range. Then making your attack run based on that where you call the shots on your time.

04-05-16, 03:46 PM	#1
Von Due Sea Lord Join Date: Jul 2012 Posts: 1,690 Downloads: 30 Uploads: 0	Pato's fixed bearing tool still in error? As many of you will know, there is and has always been some issue with bearing tools and the nav map. Pato's tool, although being a must-have to many, me included, also suffered from it. One of the old MaGui mods I still had on my HDD had a fixed image which I installed on the new WS MaGui installment of SH3/GWX3. To my surprise it was still 0.5 degrees off: I had map contacts enabled and had the sound guy track a target. Tracking lines moving clockwise, he would not report the new bearing until the tracking line hit the degree marks spot on BUT This has always, to my knowledge been a real issue, that there is a consistent rounding error in SH3 that has nothing to do with any plotting tool. Set the depth to 25 meters and the boat will most likely stop at 24.5 m. Come up from below and the boat will level at 25.5m. Turn clockwise to 90. The boat will stop turning at 89.5. Counter clockwise the boat will stop turning at 90.5. To get to 90 dead on I need to fiddle with the rudder manually to set the heading. I assume therefor that the sound guy is guilty of the same, rounding off reporting 105* when the tracking crosses nearest half. Therefor I assume that Pato's bearing tool would be correct if the tracking line was at nearest half when the sound guy reports the new bearing, NOT right on the degree mark. EDIT: Just to clarify. I know the worst was that the old graphical error was inconsistent so that eastwards had greater error than west but this I just saw here with Pato's being consistenly 0.5 off all the way reall caught me off guard. Can someone chime in here and fill me in on how this is supposed to work now after these fixes of Pato's and probably other fixes as well. No wonder my 4 point bearing showed USS Enterprise at low altitude full throttle. Off 0.5 degrees when the sound guy already has given me a full degree possible error really add up to bizarre results.

04-06-16, 09:47 AM	#4
siege00 Officer Join Date: Aug 2010 Location: USA Posts: 237 Downloads: 114 Uploads: 0	Regarding the compass variation: I wonder if they built magnetic variance into the game. There is a difference between map north and magnetic north and depending on where you are in the world, it could legitimately be .5°. It's entirely possible that the devs built that into the game, though it may be a stretch for me to even suggest it. If they did build it in or a minor facsimile of it, then that may explain a few things, though if it is built into the game, you'd figure they would've marked variation on the charts. Would be extremely cool if they did though. lol. It could've even been partially built into the game as features are trimmed for release and wasn't completely removed. Just food for thought? Or a feature in a future sim. __________________ SH3 Guide: S3G by BLITZKR!EG Currently - SH5 TWoS - SH3 GWX + MaGui and more - SH3 LSH 2015 + Ahnenerbe's Gui

04-06-16, 12:57 PM	#6
nocken Engineer Join Date: Feb 2012 Location: sheffield.uk Posts: 200 Downloads: 1763 Uploads: 0	COMPASS. MAGNETIC DIFFERENCE THE MAGNETIC DIFFERENCE IN JUNE 1940 WAS 10 DEGRESS WEST. SO LETS SAY 350 DEGRESS IS TRUE NORTH, THEN 0 DEGRESS ON COMPASS IS ACTUALLY 10 DEGRESS. SO THE QUESTION IS. DO THE IN-GAME COMPASSES TAKE IN THE DIFFERENT MAGNETIC DIFFERENCE. OR DO WE HAVE TO COMPANSATE THAT 10-11 DEGRESS DIFFERENCE.?

04-06-16, 03:39 AM	#2
Pisces Silent Hunter Join Date: Dec 2004 Location: AN9771 Posts: 4,904 Downloads: 304 Uploads: 0	I'd say that if the Uboat is spawned into the world with an exact 0 degrees N,E,S or W heading and the bearing-grid aligns perfectly to the grid on the map in the deeper zoomlevels then it is ok. I do think that one should NOT rely on the number bearings reported by the crew in the text box, or pronounced as audio. There are delays involved and indeed seems to suffer from roundoff errors. If you are not sure about the boat heading when spawning in a career you can check it by making a custom scenario and see how that aligns. If the grid aligns good to the horizontal and vertical coordinates when opened in a graphical editor then it should be ok. The original bearing grid could have been place rotated on the scanner plate. Not every one is painstaking in correcting it's orientation. The scan may even be warped or skewed (not equally wide horizontally as vertically). [edit] Even relying on the waypoint marker to get to a perfect heading (when the line is straigh) is questionable. When the heading is achieved or close enough the helmsman goes on a break until you re-command him to a new heading. It's not perfect.

04-06-16, 07:27 AM	#3
Von Due Sea Lord Join Date: Jul 2012 Posts: 1,690 Downloads: 30 Uploads: 0	For true course and navigation in game, what I do is I mark the tip of the sub icon, travel for a bit then mark again. That gives me the course I use and by comparing to the compass also any wind correction or other drift. This whole thing came up as I was practicing hydrophone only tracking, to use with the 4 bearing method. Up until now the 4 bearing method is only accurate if I have the tracking bearing lines enabled. Without them, and because I could be as much as 1.5* off when plotting, the results more often than not resulted in absurdities. One can plot various solutions to the 4 bearing method using min and max lines for bearing so say if bearing 1 is 134* then I'd draw up 133.5, 134 and 134.5, same for the other bearings. That gives 27 different outcomes for 3 bearings and 81 outcomes for the 4. and final bearing. It would be not only result in a map utterly unreadable but it would be pretty pointless as you still would have to guess which one to go for. Anyway, what may work for practical purposes with no map updates and when using Pato's tool is to allow 134 to be anything from 134* sharp to just less of 135- Average that to 134.5 on Pato's tool and use those bearings. A more advanced method includes keeping track of when the sound guy reports a new bearing using a clock mod with a seconds hand. Let's say I pick up the sound at 11:55:00 at a bearing > 135* and I'll use time intervals of 5 minutes. I spend the first 5 minutes trying to work out how often the bearing changes and if it's a CW change or CCW change. Let's say this is a CCW change at 1 minute intervals, roughly. At 12:00:00 I plot down the last known bearing. Now if the bearing changed once roughly every 1 minute and the last report was at 11:59:45 then I will draw the line at 134.75* (134.25 if the change was CW). If the last report was at 11:59:30 then I'd draw it dab in the middle at 134.5* and so on and so forth. Now it is crucial that the sound guy and Pato both agree on where a given bearing is for all bearings in any orientation. Any offset due to hardcoded f ups will throw this accuracy out of the game.

04-06-16, 10:56 AM	#5
Von Due Sea Lord Join Date: Jul 2012 Posts: 1,690 Downloads: 30 Uploads: 0	I did consider the possibility of mag north vs true north. In FSX that is a constant headache as I prefer to fly far north. In this game however I am more than a bit reluctant to accept it. They couldn't give the nav officer a stopwatch but they built in mag north? On Planet Cylinder?

04-06-16, 01:32 PM	#7
Pisces Silent Hunter Join Date: Dec 2004 Location: AN9771 Posts: 4,904 Downloads: 304 Uploads: 0	The magnetic anomaly is of little importance in this game/simulation. The boats in those times made use of gyro-compasses which aligned themselves to the poles of earth rotation by precession. Mere mechanical disturbances nudging it around. Not at all by magnetic torque. So modelling it seems redundant. Aside from that, there are many bugs that they had better had put their time on squashing them. If you want to reduce errors when working with the 4-bearing method then I suggest you increase the time interval to than a halve hour. Or whatever makes the bearing drift 5 degrees to begin with. Unless you use the periscope for bearings the bearing-error isn't likely to be much smaller than a degree.

04-07-16, 04:39 AM	#8
Von Due Sea Lord Join Date: Jul 2012 Posts: 1,690 Downloads: 30 Uploads: 0	To Nocken: Mag north is far more confusing than a fixed number like 10* west. Have a look at a map of the deviation lines for the entire planet for a given month/year and if that doesn't confuse you then I don't know what will. As for the inaccuracies in bearing, yeah greater time intervals as suggested by Pisces would get me a long way but unfortunately it seems that is a luxury I can't always afford. Sometimes I need to get it all solved in less than 20 minutes leaving only a few minutes between readings.

04-07-16, 02:05 PM	#11
Pisces Silent Hunter Join Date: Dec 2004 Location: AN9771 Posts: 4,904 Downloads: 304 Uploads: 0	Well, you don't need to hurry the procedure just because it is near. You are not forced to attack then. That is when mistakes are made, when you let the target decide what you must do. Just continuing the procedure, letting it pass while taking the bearings, would have given you (more) accurate speed and course and mk1 eyeball confirmation on the calculated/plotted range. Then making your attack run based on that where you call the shots on your time.