[Robostang 548]

I don't know if the Vex controler can support serial communication because I've never used vex before, but there is a a good gps reciver at http://www.parallax.com/detail.asp?product_id=28146 . I know my team was contemplating using this for our frc bot. If the vex controler does support serial communication then you just have to write some protocol code for the reciver and you shouldent have any problems.