A
brief overview of the Global Positioning System (GPS)
GPS
is the most sophisticated system of pinpointing a position on
earth so far developed by man. The idea was conceived in 1960,
and was developed by the U.S. military. The system was declared
fully operational in 1995. GPS
is based on the principle of radio navigation, which has
been in use since the early 20th century. Radio navigation uses
a minimum of three radio transmitter towers all broadcasting a
signal at exactly the same time. The transmitted signals all travel
at exactly the same speed, and therefore each of these signals
is detected by a receiver at a slightly different time. A calculation
of these time differences is made by the receiver to determine
how far the receiver is from each transmitter. With this information,
the receiver can determine it's exact position.
Some
vehicle location systems still use this method, but their usefulness
is limited to areas within range of the company's transmitter
towers. This method is also expensive to run, and these high costs
are inevitably passed on to customers.
The
difference with GPS is that the transmitters are satellites orbiting
20,200km above the earth . There are 24 of these satellites, all
transmitting signals, and are free for the public to use.
All
CarMinder units contain a GPS receiver, and are able to determine
their location to an accuracy typically better than 30 meters.
The
combination of GPS and mobile phone technologies is what enables
us to provide you with accurate vehicle location with no on-going
fees.
|
