GPS handheld - how it works - the satellites

There are two major parts to a gps system. The first part are the satellite systems.

The GPS satellite system consists of a large number of satellites that orbit the earth. The system is designed so that there are 9 or more satellites visible to your location at all times. They may not be the same satellites all the time but that part doesn't matter.

The satellites send a signal to earth that is received by your GPS handheld unit.

Part 2 will cover the roll of the consumer GPS devices in the GPS system.

GPS Handheld Units

There are many kinds of GPS hand held units. There are gps laptops, gps mobile phones, gps receivers for automotive navigation and gps systems for hiking, gps golf systems and other outdoor sports to name a few.

The GPS in mobile phone is interesting because the FCC mandated that all emergency calls from mobile phone had to have location information automatically passed in on the call. This is for the obvious purpose of aiding rescue services in finding and arriving to whatever emergency that might exist.