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View Full Version : Manual TDC - demystified

geezerjo09
12-11-2006, 03:47 PM
Ok here's a very theoretical way of doing your manual aiming. I havent even tried it yet put it should work, i hope it does http://forums.ubi.com/images/smilies/sadeyes.gif I think it can solve the few problems that happen when you use the map often. (We all know the map is not 100% precise and that often gets on my nerves) Two things are necessay for this method to work. 1) you have to be stationary 2) You have to assume that what your watchman tells you is precise (i mean when you ask him for nearest contact and he says "bearing 312, 3500 metres) I found him to be quite precise.

Thankfully i got pictures!!!!

http://img76.imageshack.us/img76/3776/tdcb1ue3.png (http://imageshack.us)

Ok, here's the situation. Your sub is the red dot on the bottom-centre of the screen.(remember you not moving during all of this operation) For the sake of this explanation, let us say that the blue line (although not perfectly aligned) represents true north, bearing 000. First off, your watch officer spot a merchant at bearing 339 and a distance of 14.6 km. The angle of 21o represents the reletive bearing from north. Later off, you ask you watchman for another reading of the same target. He says bearing 13, 29.3 km (i know that's impossible but it dosent really matter for this example)As you can see, I have not calculated anything yet, i have simply put in what the watchman told me.

http://img185.imageshack.us/img185/635/tdcb2xs5.png (http://imageshack.us)

What we are aiming to find out is the exact properties of the line that seperates the two dots that represent the two sightings og our prey, for now this is impossible. Lets take advantage of the magic the triangle can make!!!! Here i placed a fictional dot on the line that seperates me and the current position of the merchant. This dot is used to form 2 right angle triangles out of the old triangle. It allows us to calculate much needed information. First of all, since it is a right angle triangle, we can put 90o on the side opposite the hypotenuse (humm is that how its spelled?)this is the longest side of the triangle. Next, we add up the two angles we spotted the merchant on, 21+13=34, and add it on. Since the three angles of a triangle always add up to 180, we can do 180-(90+34)=56 and add it to the angle left. Hang in there, im not even started. As to now, almost no calculations were needed and certainly no estimation. NEXT!!!!

http://img71.imageshack.us/img71/5476/tdcb3ih1.png (http://imageshack.us)

Now comes the "hard" part. We are missing two bits of information on our triangle, the length of two sides. If you haven't done your high school you'll probably think this is impossible but it's not. Remember that sine, cosine thing? Well thats what we need. I can't really explain all of that since i have no buissness in doing that, ill simply tell you what to do with your calculator. To find the 8.2 cm value, you have to do (34*sin)*14.6 and to get the 12.1 cm value, you have to do (56*sin)*14.6. That's all. Simple no? Now do it without your calculator. HAHAHAHA. Ok enough with the jokes, NEXT!!!!

http://img185.imageshack.us/img185/7541/tdcb4eo9.png (http://imageshack.us)

This one is easy, now we have to solve the second right angle triangle. The 90o i added is a no brainer, do i even have to explain that one? 17.2cm is also easy. 29.3-12.1=17.2 Ok lets do this

http://img185.imageshack.us/img185/4751/tdcb5pu2.png (http://imageshack.us)

Now it gets rough. This is maybe the hardest part, so dont panic if you feel stupid. We have to use that sin and cosine thing again to get the two angles (64 and 26). Actually its the tangent we use this time, its probably written tan on your calculator. Oh wait, actually its the -tan we use, you were worried werent you? Ok heres the calculation. (8.2/17.2)*-tan you should get around 26 ( my picture is not 100% acurate) Then you can simply do like in the other triangle
180-(90+26)=64 to fill in the last angle.

http://img71.imageshack.us/img71/2994/tdcb6tf6.png (http://imageshack.us)

This one is pretty much like #3 but a bit different. Anyhow here's how you get the 19.1 value. 17.2/(64*sin)= 19.1. 19.1 represents the distance the merchant travelled between the first time you spotted him and the second. You can easily find speed of target if you took care to time this.

http://img184.imageshack.us/img184/1572/tdcb7ab7.png (http://imageshack.us)

Once you have the speed and course of your target, hes dead. Now that we have speed, lets get his course. Here, i continued both the lines that represent the angle at with i spotted the merchant last and his course. You can add the 26o because two lines that cross each other automatically have the same angle on opposit sides. Hey only one picture left!!!!!

http://img184.imageshack.us/img184/2743/tdcb8xl0.png (http://imageshack.us)

The last blue line I added is actually bearing 000 and parallel to the first blue line. This is a 3d application thingy and it tries to be 3d-ish, so it points true north, trust me. Wow, before i finish this thing, lets take a moment to admire that last picture, isn't nice? I truely surpassed myself.God i'm good. Ok so this last number, 13o, can be added because of a known carateristic of lines. Something like "two parallel lines create the same angle when crossed by another line" Basicaly, its the same angle you see the merchant at. Course of merchant =13+26=39. Ok i'm done. Youppi! I hope you understood cause i realized i didnt explain enough, im not even sure anyone is gonna read this so why should I? If people ARE interested ill try to answer any question i can. Next week ill try to come up with the same method but then on the move. OWWWWW! thats gonna be hard. Stop.

geezerjo09
12-11-2006, 03:47 PM
Ok here's a very theoretical way of doing your manual aiming. I havent even tried it yet put it should work, i hope it does http://forums.ubi.com/images/smilies/sadeyes.gif I think it can solve the few problems that happen when you use the map often. (We all know the map is not 100% precise and that often gets on my nerves) Two things are necessay for this method to work. 1) you have to be stationary 2) You have to assume that what your watchman tells you is precise (i mean when you ask him for nearest contact and he says "bearing 312, 3500 metres) I found him to be quite precise.

Thankfully i got pictures!!!!

http://img76.imageshack.us/img76/3776/tdcb1ue3.png (http://imageshack.us)

Ok, here's the situation. Your sub is the red dot on the bottom-centre of the screen.(remember you not moving during all of this operation) For the sake of this explanation, let us say that the blue line (although not perfectly aligned) represents true north, bearing 000. First off, your watch officer spot a merchant at bearing 339 and a distance of 14.6 km. The angle of 21o represents the reletive bearing from north. Later off, you ask you watchman for another reading of the same target. He says bearing 13, 29.3 km (i know that's impossible but it dosent really matter for this example)As you can see, I have not calculated anything yet, i have simply put in what the watchman told me.

http://img185.imageshack.us/img185/635/tdcb2xs5.png (http://imageshack.us)

What we are aiming to find out is the exact properties of the line that seperates the two dots that represent the two sightings og our prey, for now this is impossible. Lets take advantage of the magic the triangle can make!!!! Here i placed a fictional dot on the line that seperates me and the current position of the merchant. This dot is used to form 2 right angle triangles out of the old triangle. It allows us to calculate much needed information. First of all, since it is a right angle triangle, we can put 90o on the side opposite the hypotenuse (humm is that how its spelled?)this is the longest side of the triangle. Next, we add up the two angles we spotted the merchant on, 21+13=34, and add it on. Since the three angles of a triangle always add up to 180, we can do 180-(90+34)=56 and add it to the angle left. Hang in there, im not even started. As to now, almost no calculations were needed and certainly no estimation. NEXT!!!!

http://img71.imageshack.us/img71/5476/tdcb3ih1.png (http://imageshack.us)

Now comes the "hard" part. We are missing two bits of information on our triangle, the length of two sides. If you haven't done your high school you'll probably think this is impossible but it's not. Remember that sine, cosine thing? Well thats what we need. I can't really explain all of that since i have no buissness in doing that, ill simply tell you what to do with your calculator. To find the 8.2 cm value, you have to do (34*sin)*14.6 and to get the 12.1 cm value, you have to do (56*sin)*14.6. That's all. Simple no? Now do it without your calculator. HAHAHAHA. Ok enough with the jokes, NEXT!!!!

http://img185.imageshack.us/img185/7541/tdcb4eo9.png (http://imageshack.us)

This one is easy, now we have to solve the second right angle triangle. The 90o i added is a no brainer, do i even have to explain that one? 17.2cm is also easy. 29.3-12.1=17.2 Ok lets do this

http://img185.imageshack.us/img185/4751/tdcb5pu2.png (http://imageshack.us)

Now it gets rough. This is maybe the hardest part, so dont panic if you feel stupid. We have to use that sin and cosine thing again to get the two angles (64 and 26). Actually its the tangent we use this time, its probably written tan on your calculator. Oh wait, actually its the -tan we use, you were worried werent you? Ok heres the calculation. (8.2/17.2)*-tan you should get around 26 ( my picture is not 100% acurate) Then you can simply do like in the other triangle
180-(90+26)=64 to fill in the last angle.

http://img71.imageshack.us/img71/2994/tdcb6tf6.png (http://imageshack.us)

This one is pretty much like #3 but a bit different. Anyhow here's how you get the 19.1 value. 17.2/(64*sin)= 19.1. 19.1 represents the distance the merchant travelled between the first time you spotted him and the second. You can easily find speed of target if you took care to time this.

http://img184.imageshack.us/img184/1572/tdcb7ab7.png (http://imageshack.us)

Once you have the speed and course of your target, hes dead. Now that we have speed, lets get his course. Here, i continued both the lines that represent the angle at with i spotted the merchant last and his course. You can add the 26o because two lines that cross each other automatically have the same angle on opposit sides. Hey only one picture left!!!!!

http://img184.imageshack.us/img184/2743/tdcb8xl0.png (http://imageshack.us)

The last blue line I added is actually bearing 000 and parallel to the first blue line. This is a 3d application thingy and it tries to be 3d-ish, so it points true north, trust me. Wow, before i finish this thing, lets take a moment to admire that last picture, isn't nice? I truely surpassed myself.God i'm good. Ok so this last number, 13o, can be added because of a known carateristic of lines. Something like "two parallel lines create the same angle when crossed by another line" Basicaly, its the same angle you see the merchant at. Course of merchant =13+26=39. Ok i'm done. Youppi! I hope you understood cause i realized i didnt explain enough, im not even sure anyone is gonna read this so why should I? If people ARE interested ill try to answer any question i can. Next week ill try to come up with the same method but then on the move. OWWWWW! thats gonna be hard. Stop.