Sunday, September 23, 2007

What is a GPS System?

GPS stands for “Global Positioning System.” A GPS is a Global Navigation Satellite System that uses a number of satellites to send transmission data from earth, to the satellite, and back again.

A Global Positioning System requires the use of a receiver that enables the system to determine elements such as location, time, direction, and speed.

Today, it is common to see cars that have GPS systems included, however you may be surprised to discover that the GPS system was designed and developed by the United States Department of Defense. Originally, the system was referred to as the Navstar GPS, but today people simply refer to it as a GPS.

In addition to all of the military uses for a GPS system, civilians have found it to be an incredible navigational tool that is conductive for every day life.

If your car is stolen, you can track where it has been taken with GPS. You can program in your point of departure and destination and your GPS will give you complete directions for a trip. It can tell you how long your trip will take and the exact route you should take.

The GPS system is comprised of twenty-four satellites that circle the earth twice per day. The receiver contacts the satellite and in turn, can return a user’s exact location, including the time that the data was received from the satellite.

What is fascinating to note, is that when the satellite receives the information regarding the user’s location, it determines where the person is located, based on the amount of time it takes for the satellite to obtain the information from the receiver. This is a process known as triangulation.

Since there are twenty-four satellites in orbit, the GPS system doesn’t just rely on the information obtained from one. It uses several more satellites to create a latitude and longitude reading. Then, the system begins to add all of the coordinates and information together and creates an electronic map.

Today’s GPS systems are extremely accurate. The twenty-four satellites are constantly in motion, circling the earth. They have been estimated to travel at speeds of 7,000 miles per hour. They receive information by transmitting signals. The signals are low radio frequencies on channels L1 and L2.

However, although today’s GPS systems are far superior to when they were first in operation, back in 1978, there are still factors that can cause faulty signals and data.

Some of the most common factors that can affect the signal and its accuracy include delays in the Ionosphere and Troposphere, Signal multipaths, Clock errors in the receivers, Errors in Orbit, The number of Satellites that are visible, and a weak satellite signal.

The uses of a GPS system are vast, and they have helped increase and enhance safety for our citizens. In addition, the GPS system is a phenomenal navigational tool that is vital to every traveler.

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