A global positioning system (GPS) device can be located anywhere on the planet with a high degree of accuracy. In order to locate a GPS device, you will need to have some method of looking up the latitude and longitude coordinates of the device, and a means of placing those coordinates on a global map. This is usually simple if you are carrying the device, but requires some planning if you are tracking a device remotely.

How Global Positioning Works

A GPS device is in contact with a network of orbiting satellites, whose position relative to the earth is precisely known at all times. GPS signals from your device to these satellites are timed to determine how long it took the speed of light (which is also the speed of radio waves) to reach the satellite. When you're in contact with two or more satellites, your position can be triangulated by measuring the difference in distance to each one.

Latitude and Longitude

Your position is calculated and reported back to you on the device in latitude and longitude coordinates. This is a conceptual grid which covers the planet and provides a mathematical position for every location. Once you have these coordinates, use them with a map or mapping software to determine a GPS device's position. On most GPS devices, a map will be incorporated into the device, but in some cases you will need to retrieve the coordinates from the device and correlate them on a computer or by hand.

Tracking GPS Devices Over a Distance

If you want to track a GPS device which you will not be carrying, you will need a device which incorporates a cell phone, radio, or other method of sending its coordinates to a central server which you can access. One such method is Google Latitude, which works with GPS-enabled cell phones; once a cell phone has been registered with the service, registered users associated with the account can track the location and movement of the phones on an integrated map. These services have obvious privacy implications, so they must be set up in advance, and the owner of the GPS device must give online permission to whomever is allowed to track the device.

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Using the GPS for People Tracking

Latitude and Longitude

Google Latitude