| GPS stands for Global Positioning System. Basically it | | | | information back, it then displays its location on the |
| means being able to locate anything in a certain | | | | monitor's map. |
| position on the globe through the use of satellite | | | | The design of the GPS receiver makes the device |
| tracking. Most people are familiar with GPS tracking for | | | | extremely accurate even in areas where there may |
| cars, but it can be used to track anything that has an | | | | be interference from very high buildings such as |
| appropriate device attached that can send a signal. | | | | skyscrapers. The newest receivers use what is called |
| The system works through a series of satellites that | | | | a WAAS (wide area augmentation system) which can |
| continuously orbit the Earth. It was originally designed | | | | greatly improve the transmission of the GPS device. |
| by the U.S. military to use for navigational purposes. | | | | Of course the units vary in construction depending on |
| The satellites themselves weigh between 3,000 - | | | | the manufacturer of the product. If you are considering |
| 4,000 pounds and travel at a speed of 12,000 miles, | | | | using GPS tracking for cars, talk to your local |
| which means they make two complete rotations | | | | authorized dealer to make sure you get the exact |
| around the Earth every day. The satellites are | | | | device you want to have. |
| arranged in the atmosphere above the Earth. At any | | | | The first GPS satellite ever launched into space was in |
| given time there are four that are visible in the sky as | | | | 1978. Even though there are now 27 in total, only 24 of |
| seen from the surface of the Earth. A GPS unit that is | | | | them are actually operational at this time. The satellites |
| used as a receiver sends its signal out to one of the | | | | are built to have a life expectancy of about 10 years. |
| four satellites in its area. The satellite sends the signal | | | | There are some external factors that can cause |
| back to the receiver and this how a GPS tracking | | | | interference in the transmissions to and from the |
| device can determine its position on the Earth. | | | | satellites. The ionosphere itself can cause the signal to |
| Another factor in using the satellites to determine an | | | | slow down, although the satellites are built to take this |
| object's location is time. By using the four satellites | | | | delay into consideration when sending signals. The |
| within its signal range, the satellites determine the time | | | | signal path can also be interrupted by having it bounce |
| the signals were sent in conjunction with how far | | | | off of other surfaces before reaching the satellite. And |
| away the satellite is to determine the exact location of | | | | on Earth, the GPS receiving unit itself can also have an |
| the object. The GPS receiver actually sends its signal | | | | internal clock error which could read the signal back |
| to more than one satellite to determine its exact | | | | wrong and cause it to place itself in a different location. |
| position. When the GPS device receives the | | | | |