What does position have to do with Global Positioning System?

Answer 1

GPS provides position/location information. It is similar to that the phone company can track you phone location with the signal strength received by at least 2 cell phone towers. If only one cell phone tower, the phone signal can only be interpreted as that the phone is somewhere in the circle of a known radius, assuming at ground level. With two cell phone towers, the phone signal can be narrowed to two possible locations. With three cell phone towers, the phone location is narrowed down to a small region, say within a city block. In the GPS, the cell phone towers are replaced by satellites. A hand-held GPS unit can use the signals from 4 satellites to calculate the coordinates (x,y,z) of the location and also how fast the unit is moving.