## Usable trilateration? (Circles intersection)

Hey guys,

As a part of my Thesis I am developing an open-source location based services framework however I am starting to struggle with one aspect of the code - Trilateration.

I've spents hours and hours researching how this may be done and I've found quite a few leads (Sadly a little outside of my mathmatical knowledge!).

Before I go into any more detail, let me give you a give brief of the constants.

We have n>3 known coordinates (Longitude, latitude and elevation [altitude]) with an estimated coverage [radius].

My aim is to estimate the 2 dimentional location of the centre of these cordinates (via Trilateration [strike]Triangulation[/strike]).

From what I've found, I think it can be done through a few formulas based "circles intersection".

The most promising formula I've found is: "Apollonius' Tangency Problem"

Does anyone have any hints or tips?

ps: sorry for the random keywords, I've had a nightmare searching for help on this topic, hopefully those keywords will bring anyone else struggling with it here