gps satellites position
How do GPS satellites stay in perfect position with out drifting out of position in time?
Seems that no matter how perfectly positioned these GPS satellites are they would drift out of position and that would throw off the computations of our GPS units in cars etc.
The GPS satellites orbit the earth twice a day. It isn’t necessary for them to stay in perfect position. The crucial point is that each satellite should “know” where it is. Tracking stations around the world allow the orbits of the satellites to be calculated, that information is sent to the satellites and the satellites, in turn, broadcast that data to the GPS receiver on the ground. When a GPS receiver picks up broadcasts from 4 or more satellites, it can determine its position relative to those satellites and hence derive its geographical location.
