Convert Earth Coordinate to Local Coordinate after Trilateration

I have done coding of Trilatera开发者_如何学编程tion following this example and it was really very helpful. One small help I need is. The results (X, Y, Z) returned here are based in Earth Coordinate Systems. I need to convert it into local coordinate system to place it in a map. I have found some suggestion of converting to local coordinate from lat long(For example : this). But I was just wondering is it possible to change the coordinate directly from the Earth coordinate system?

Yes, assuming your local coordinates are East, North, Up (ENU):

http://en.wikipedia.org/wiki/Geodetic_system#From_ECEF_to_ENU