What is and how does a GPS work?
What is and how does a GPS work? The Global Positioning System
(GPS) is a satellite-based navigation system made up of a
network of about 18-24 satellites placed into orbit. GPS was
originally intended for military applications, but in the late
1970s, the government made a system available for civilian use.
GPS works in any weather conditions, anywhere in the world,
24/7. There are no cost for the use.
How it works
GPS satellites circle the earth twice a day in the same orbit
and transmit signal information to down to mother earth. GPS
take this information and use triangulation to calculate the
user's exact location. The GPS receiver compares the time a
signal was transmitted by a satellite with the time it was
received. The time difference tells the GPS receiver how far
away from the satellite it is. Now, with this distance
measurements from a few more satellites, the receiver can
determine the user's position and display it on the unit's
electronic map.
A GPS receiver must be locked on to the signal of at least three
satellites to calculate a 2d position (latitude and longitude)
and track movement. With four or more satellites in view, the
receiver can determine the user's 3D position (latitude,
longitude and also altitude). Once the user's position has been
determined, the GPS unit can calculate other information, such
as speed, track, trip distance, distance to destination, sunrise
and sunset time and a lot more. How accurate is GPS? Today's GPS
receivers are extremely accurate, thanks to parallel
multi-channel design. Garmin's 12 parallel channel receivers are
quick to lock onto satellites when first turned on and they
maintain strong locks, even in dense foliage or urban settings
with tall houses. Certain atmospheric factors and other sources
of error can affect the accuracy of GPS receivers. Garmin