SAR Fundamentals/Navigation/Map/Triangulation/Samples - Revision history

Brett Wuth at 08:02, 8 December 2018

2018-12-08T08:02:14Z

←Older revision		Revision as of 08:02, 8 December 2018
Line 1:		Line 1:
-	~~See {{nbw\|2016\|10\|26}}~~
-
	<pre>		<pre>
	LE = local east		LE = local east

Brett Wuth at 03:19, 27 October 2016

2016-10-27T03:19:21Z

←Older revision		Revision as of 03:19, 27 October 2016
Line 1:		Line 1:
		+	See {{nbw\|2016\|10\|26}}
		+
	<pre>		<pre>
	LE = local east		LE = local east

Brett Wuth at 03:18, 27 October 2016

2016-10-27T03:18:20Z

←Older revision		Revision as of 03:18, 27 October 2016
Line 55:		Line 55:
	915786 70 866784 296 887775		915786 70 866784 296 887775
	915786 60 866784 304 889770 !!890768		915786 60 866784 304 889770 !!890768
-	<pre>	+	</pre>

	* Can generate more samples, but make sure points are visible on the map.		* Can generate more samples, but make sure points are visible on the map.

Brett Wuth at 06:57, 8 February 2013

2013-02-08T06:57:42Z

←Older revision		Revision as of 06:57, 8 February 2013
Line 1:		Line 1:
	<pre>		<pre>
-	~~Material Covered:~~
-	* triangulation
-
-	~~Prerequisites:~~
-
-
-	~~Objective:~~
-	~~Students w~~
-
-	~~Duration: 45 minutes~~
-
-	~~Aids:~~
-
-	~~Plan:~~
-
-
-
	LE = local east		LE = local east
	LN = local north		LN = local north
Line 45:		Line 28:
	LN = (- tan(R2B)R2N + R2E + tan(R1B)R1N - R1E)/(tan(R1B) - tan(R2B))		LN = (- tan(R2B)R2N + R2E + tan(R1B)R1N - R1E)/(tan(R1B) - tan(R2B))
	LN = (tan(R1B)R1N - tan(R2B)R2N + R2E - R1E)/(tan(R1B) - tan(R2B))		LN = (tan(R1B)R1N - tan(R2B)R2N + R2E - R1E)/(tan(R1B) - tan(R2B))
		+	</pre>

		+	<pre>
	On a line with a bearing to a remote point		On a line with a bearing to a remote point
	Line,RemoteUTM,TNBearingToRemote,LocalUTM		Line,RemoteUTM,TNBearingToRemote,LocalUTM
Line 70:		Line 55:
	915786 70 866784 296 887775		915786 70 866784 296 887775
	915786 60 866784 304 889770 !!890768		915786 60 866784 304 889770 !!890768
		+	<pre>

-	* Can generate more samples,	+	* Can generate more samples, but make sure points are visible on the map.
-	but make sure points are visible on the map.	+	<pre>
	wuth@errant$ utm-triangulate 915786 70 866784 295 2 5		wuth@errant$ utm-triangulate 915786 70 866784 295 2 5
	888775		888775
	wuth@errant$		wuth@errant$
-		+	</pre>


Line 84:		Line 70:
	answer.		answer.

-		+	<pre>
	Accuracy Sources of Error:		Accuracy Sources of Error:
	UTM rounding:		UTM rounding:
Line 123:		Line 109:
	5 degree error in 1km is 87m left/right		5 degree error in 1km is 87m left/right
	10 degree error in 1km is 176m left/right		10 degree error in 1km is 176m left/right
-
	</pre>		</pre>

Brett Wuth: SAR Fundamentals/Navigation, part 1/Sample Triangulations moved to SAR Fundamentals/Navigation/Map/Triangulation/Samples

2012-02-06T02:42:46Z

SAR Fundamentals/Navigation, part 1/Sample Triangulations moved to SAR Fundamentals/Navigation/Map/Triangulation/Samples

←Older revision

Revision as of 02:42, 6 February 2012

Brett Wuth: New page:

 Material Covered:   * triangulation  Prerequisites:       Objective:      Students w  Duration: 45 minutes  Aids:  Plan:    LE = local east  LN = local north L1B = bearing to remote ...

2011-02-26T22:38:36Z

New page: <pre> Material Covered: * triangulation Prerequisites: Objective: Students w Duration: 45 minutes Aids: Plan: LE = local east LN = local north L1B = bearing to remote ...

New page

<pre>
Material Covered:
* triangulation

Prerequisites:

Objective:
Students w

Duration: 45 minutes

Aids:

Plan:

LE = local east
LN = local north
L1B = bearing to remote 1
L2B = bearing to remote 2
R1E = remote 1 east
R1N = remote 1 north
R1B = bearing from remote 1
R2E = remote 2 east
R2N = remote 2 north
R2B = bearing from remote 2

R1B = L1B - 180
R2B = L2B - 180
(LE-R1E)/(LN-R1N) = tan(R1B)
(LE-R2E)/(LN-R2N) = tan(R2B)

LE-R1E = tan(R1B)*LN - tan(R1B)*R1N
LE-R2E = tan(R2B)*LN - tan(R2B)*R1N

LE = tan(R1B)*LN - tan(R1B)*R1N + R1E
LE = tan(R2B)*LN - tan(R2B)*R2N + R2E

tan(R1B)*LN - tan(R1B)*R1N + R1E = tan(R2B)*LN - tan(R2B)*R2N + R2E
tan(R1B)*LN = tan(R2B)*LN - tan(R2B)*R2N + R2E + tan(R1B)*R1N - R1E
tan(R1B)*LN - tan(R2B)*LN = - tan(R2B)*R2N + R2E + tan(R1B)*R1N - R1E
(tan(R1B) - tan(R2B)) * LN = - tan(R2B)*R2N + R2E + tan(R1B)*R1N - R1E
LN = (- tan(R2B)*R2N + R2E + tan(R1B)*R1N - R1E)/(tan(R1B) - tan(R2B))
LN = (tan(R1B)*R1N - tan(R2B)*R2N + R2E - R1E)/(tan(R1B) - tan(R2B))

On a line with a bearing to a remote point
Line,RemoteUTM,TNBearingToRemote,LocalUTM
Cutline 929760 893792 ,915786, 90,900785
Cutline 929760 893792 ,915786, 76,903783
Cutline 929760 893792 ,915786, 45,908779
Cutline 929760 893792 ,915786, 0,916772
Cutline 929760 893792 ,915786,336,927762
Left Bank of Castle River,915786,320,936763
Left Bank of Castle River,915786,270,938787
Left Bank of Castle River,915786,250,940793

Cutline 103766 078767 ,086757,226,095766
Right Bank of West Castle,897680,187,900718

82G/8 Zone 11, Grid North is 2deg 5min east of TN
Remote1UTM,TNBearingToRemote1,Remote2UTM,TNBearingToRemote2,LocalUTM
915786 56 866784 316 886765
915786 67 866784 344 872766
086757 148 045776 272 073776
086757 130 045776 229 053783
016628 283 013665 187 026626 !! degrees backwards
=915786 70 866784 295 888775 harder to be accurate b/c of relative angle
915786 70 866784 296 887775
915786 60 866784 304 889770 !!890768

* Can generate more samples,
but make sure points are visible on the map.
wuth@errant$ utm-triangulate 915786 70 866784 295 2 5
888775
wuth@errant$

Fancy thing about the utm-triangulate calculation is that you can get
either or both bearings 180 degrees backwards and you still get the same
answer.

Accuracy Sources of Error:
UTM rounding:
UTMs are only to nearest 100m, can be out by sqrt(2*50m^2)=71m

Measuring angles on the map:
When points close together UTM rounding is exagerated.
want the points to be far apart.
But if actually moving to the point, close point is not necessary.

User Error:
* misreading compass
* metal objects

Compass Inaccuracies:
* gradients only ever 2 degress -> estimate difference
* needle not exactly magnetic north -> learn calibration of compass

Environment
* local variants in declination
* shifting magnetic pole
* progressive
* daily 100 km elipse

Geometry
* Parallax -> sight on close by objects when point to angle
sight on object close to destination when angle to point
* Earth's curvature
West is not a straight line
remembered: 1 degree / 100 mi at 49 degrees N

Triangulate with 3 bearings
get a triangle of results

1 degree error in 1km is 17m left/right
2 degree error in 1km is 35m left/right
5 degree error in 1km is 87m left/right
10 degree error in 1km is 176m left/right

</pre>