SUBSIM Radio Room Forums - View Single Post - Pato's fixed bearing tool still in error?

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.

04-06-16, 07:27 AM	#2
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.