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I read Trilateration using 3 latitude/longitude points, and 3 distances? explaining about trilateration using 3 latitude and longitude with measured distance.

The problem is I want to find out an unknown target location with only 3 knowns latitude and longitude co-ordinates without knowing each distance point. For example, I have 3 following longitudes and latitudes:

lat="-6.28530175" lon="106.9004975375"
lat="-6.28955287" lon="106.89573839"
lat="-6.28388865789474" lon="106.908087643421"


Based on @D.E.Wright answer I am googling to find out more and I get this following forum http://www.coderanch.com/t/453432/Programming/implement-cell-triangulation-mobile-phones, it gives 3 steps to triangulation. The problem I couldn't understand what he means about "Calculate distance from the first tower based on speed which gives a radius value".

And with @Kirk Kuykendall suggestion I decide to put my 3 lat/long to google map and I get this following image :

Google Maps

Where :
A, B, C : Cell Towers location
A : lat -6.28955287, lon 106.89573839 with cell tower Radius 6000m
B : lat -6.28530175, lon 106.9004975375 with cell tower Radius 6000m, and
C : lat -6.28388865789474, lon 106.908087643421 with cell tower Radius 6000m

Now, with these data can I doing a triangulation to get my real position and how is the mathematical method?

I've tried to modify Python code to remove the distance variable from @wwnick in Trilateration using 3 latitude/longitude points, and 3 distances? but until now I couldn't find the answer.

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2 Answers 2

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Yes, I agree that I don't see how to get exact location without a distance. You would be in this situation:

enter image description here

So you would only be able to tell within a certain area where you were. And that's with only a 1000m buffer (radius). Your 6000m buffer has such an overlap that the potential location would be huge.

The solutions would be to:

  1. Get some sort of distance measurement (even if it's approximate)
  2. Use more cell towers
  3. Use better placed cell towers

By better placed cell towers I mean that these three form a very flat triangle. A more equilateral triangle would give smaller areas of overlap, meaning a more accurate position.

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Your answer will have you doing concentric circles radiating out from each point; when all three intersect you will have our point. So you may have one radius of 15 miles, one of 10 miles and one of 25 miles, but at a point in space all three will intersect of have a mean point to intersect that will represent you originating point.

In EMS we use this triangulation method from Cell Towers a lot; but its programatic from our side since a cell signal doesn't give your range or bearing you need to use triangulation.

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