GPS is a bunch of satellites circling the earth. That send out their position. Your tablet (and phone) has a GPS receiver that calculates those positions into your own position on earth. So it's kind of passive. In that your tablet does not have to send any signals out. Just calculate position signals coming in and triangulate your own position on earth. Make sense?
SO no special service is needed. The government originally set GPS up to provide location data for the military. Everything from troop movements to gps guided missiles. Then several decades ago they dumbed it down and gave everyone access. It's since become more accurate. And usable for mapping purposes on our phones and tablets. Without it we wouldn't have things like Google Maps. Or any of our mapping and navigational tools we use today.
reddvltj - I've set up a hotspot one time with my current cell phone. For the head unit in my Yukon. It worked. But I did not play with it or use it much. Once it's set up. What is the time involved to getting say your tablet on the internet once your phones fired up and giving it internet access? I mean could I set it up easily in the morning. Move to and from my car with my cell phone. And come back several times during the day. And still have internet access on my tablet?