The Global Positioning System is a satellite-based navigation system
put into place by the U.S. Department of Defense and is a network made
up of 24 satellites in orbit around the earth. The satellites orbit the
earth at about 12,000 miles, are solar powered, they transmit a signal
of only 50 watts, and travel at speeds of about 7000 miles per hour.
The GPS system was originally intended for military use only, but
during the 1980s the government decided to allow civilian use. The
satellites make a complete orbit around the earth every 24 hours, and
are spaced equal distances from each other.
Now that we have covered most of the equipment information, let’s talk
about what a GPS can do, and why we have such technology. The GPS
system allows for satellite tracking of just about anything to which
you can attach a tracker. The GPS system is accurate to within about 15
meters from anywhere on earth. This is some amazing technology, yet it
is still relatively new to the average consumer.
The trick in the operation of this system is the tracking of the
signal, with formulas thrown in to account for the delay in the
transmission of the signal, and atmospheric changes. Since there are
other satellites available to provide a sort of numbers game for the
GPS, a pretty definite location can be determined using the GPS.
What other pieces of information can be gleaned from the use of the
GPS? Other pieces of information like speed, bearing, track, trip
distance, distance to destination, sunrise and sunset. That’s a pretty
amazing piece of work, how did this GPS come to be in existence?
The Department of Defense originally commissioned the work for a
military purpose only. But during the 1980s it was decided that the
consumer and commercial industry would benefit greatly, and there was
little or no security issues for the military. The military and
civilians alike use two low frequency channels for signal
communication. The civilian GPS transmits on L1 at a frequency of 1575
MHz. Most of the signal travel by sight, but will not transmit through
solid buildings or structures.
In order to relate this to something the average consumer will
understand and appreciate, OnStar, the communication system that now
comes in many of the automobiles we buy, utilizes technology like this
in order to determine your location in emergency situations. We don’t
often stop to think about the GPS system and the benefits provided to
us, until our car won’t start and we push the OnStar button... and this
nice voice says, “This is OnStar, how can we help you?”
