I am getting ready to go on vacation, and I had a question about my phone's GPS...?

I have one of Virgin Mobile's Android smartphones, which has Google Navigation on it, and I was planning on using it to guide me to a house my friends and I rented at the beach. However, looking at Sprint's coverage map, there are a lot of dead zones between here and my destination. I was wondering if my phone's GPS was dependent on cell or 3G reception, or if it connects to a GPS satellite. I would really hate to get stuck in West Virginia. Thanks for your help.