GPS (Global Positioning System) tracking devices come in all shapes and sizes and can be used to monitor the movement of vehicles, assets, boats and vulnerable persons, children and animals. GPS systems can provide reliable positioning, navigation and timing data in all weathers, day and night anywhere in the world.

A typical unit will consist of a GPS receiver interfaced with a GSM engine (radio and satellite systems are also available).  The GPS unit receives three dimensional location signals (Latitude, longitude and altitude, along with time) from a constellation of between 24 and 32 U.S. medium orbit satellites.

This data is then communicated by SMS text to the monitoring station. The monitoring station could be a mobile from which the data is inputted directly into a SATNAV system, or a PC with customised mapping software.

The prime function of GPS tracking devices is to allow the user to pinpoint the exact location of the tracker at any given time; however, different makes vary in their added functionality. Common features are the ability to download historical data to allow the user to determine where a tracking device has been, including precise timings, which routes it has taken and at what speed.

Other features sometimes include an alarm function which alerts the user when a device starts to move or stops, or when it enters or exits a particular area or route. Tracking devices can be used covertly or overtly. When used covertly they are excellent aides to surveillance and are normally attached to the underside of vehicles or built into the host vehicle. They can also be hidden inside in all manner of high-value goods – big or small – enabling the user to locate the goods containing the device during the normal course of events and, most particularly, if they are stolen. Similarly, their overt use – in the case of vulnerable people or animals – provides timely and accurate information about the location, direction and speed of the host.