Some Functions of Satellites

Communications: Microwaves travel in straight line, which once limited the range of television and radio transmitters. Distant signals would be lost in space. Now communications satellites relay signals from one location to another on the ground, or from one satellite to another, allowing transmissions to be sent worldwide instantly. This allows radio, television and telephone signals to be sent virtually anywhere.
GPS: Global positioning satellites use time and distance to determine location. By measuring the time it takes for a signal to travel between two points, the GPS systems can find out exactly where a transmitter is.
Mapping and Remote Sensing: These satellites use cameras to collect information about land formations and the environment. Predictions are more accurate and warnings can be issue far in advance of dangerous storms.