Does iPhone GPS work without Cell Coverage?

This is for Rotor-Heads question.

Handheld GPS uses the network of satellites to get your location, while A-GPS (Assisted GPS); which is what our iPhones use, uses the network of satellites along WITH information from the cell towers of your mobile operator to pinpoint your location. This added dimension makes A-GPS faster and more accurate - only if you are near a cell tower. Also, the A-GPS only works if there is a cell tower, and you do not have to be on a purchased cell service for this to work. But, if you are in the middle of ocean, or putting around flying VFR, it doesn’t work the same as a hand held GPS that actually acquires Satellite Signals, and doesn’t use a hybrid A-GPS system.