My comment would be that you would do well to benchtest the ideas with PC based kit, hell, start with the light sources on a desktop, with a detector sat on top of a protractor and see if you can measure your position blind, using a calculator. If you do THAT move up to a PC and automate the calculations. THEN move to an embedded micro, and all the headaches that makes !

This thing may also live and die on the quality of your mechanics, so don't skimp on mechanical design to get to the sexy bits you all want to play with, as it were.

Steve