Tom Clarke – How does the GPS work?

How does the GPS work?

Three major parts make up the GPS.

1. Pseudorandom code: Identifies which satellite is transmitting information to the receiving GPS unit.

2. Ephemeris data: Each satellite transmits ephemeris data. Identifying where the individual GPS is at anytime. Also showing the orbital information for that satellite and other satellites.

3. Almanac data: Essential part in determining a position. Constantly transmitting data from each satellite (functioning or not) with the current date and time.

The GPS satellites circle the earth twice a day while transmitting a signal to earth.  The receiver then takes that data and uses triangulation in calculating the receiver’s exact location.  The signal travels by a line of sight, meaning they do not “see” through most solid objects such as buildings, walls etc.  Clouds can also disrupt the signal.

Tom Clarke