GPS Vehicle Tracking

A GPS tracking unit is a device, normally carried by a moving vehicle or person, that uses the Global Positioning System (GPS) to track the device’s movements, at intervals, and to determine its location, and its carrier. The recorded location data can be stored within the tracking unit, or it may be transmitted to a central location database, or Internet-connected computer, using a cellular (GPRS or SMS), radio, or satellite modem embedded in the unit. This allows the asset's location to be displayed against a map backdrop either in real time or when analysing the track later, using GPS tracking software. Data tracking software is available for smartphones with GPS capability.

A GPS "track me" essentially contains a GPS module that receives the GPS signal and calculates the coordinates. For data loggers it contains large memory to store the coordinates, data pushers additionally contains a GSM/GPRS modem to transmit this information to a central computer either via SMS or GPRS in form of IP packets.

There are three types of GPS trackers, though most GPS-equipped phones can work in any of these modes depending on mobile applications installed:

GPS loggers log the position of the device at regular intervals in its internal memory. GPS loggers may have either a memory card slot, or internal flash memory card and a USB port. Some act as a USB flash drive, which allows downloading of the track log data for further analysis in a computer. The track list or point of interest list may be in GPX, KML, NMEA or other format.

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Wikipedia