[russell]

you dont need any subscription to use a gps, it simply has a clock in it, then receives signals from the satelites that tell the location of the satelite, and the time of transmission. Using this they can compute their distance from the satelite, then when they get multiple signals they can use trig to figure their position. The only problem is that I am not sure it is legal to receive data from anything other than the radio modems. In addition to the problems I pointed out above of accuracy. And price. As for having a pic power one that shouldnt be a problem. Most GPSs have ports that they use to send their position and such to a computer or whatever. Lots of people use gpss on robots, just they usually dont want their position down to a foot or so.