GPS ist Global Positioning System what means, you will receive Signals from satellites to triangulate your longitude and latitude.
GPRS ist an old Mobile Phone communication standard but mostly available because better one should have fallback to that one. You should find out something about the frequency is used in your area.
It is no example like you expect maybe. Technical Machine is still a small but highly innovative Company been watched by many leading players. Also you have to know everything is Open Source ... including the Hardware. So you would be able to build your own Tessel with much more work but cheaper maybe.
I had the same question before about half a year. The result is, the awesome team will present a solution at the end of February as they wrote on the blog.
Now two non native speakers had a talk (I am a German). Hopefully the Americans understand what we talk about LOL