GPS Tracker
A GPS tracking unit is a navigation device, normally carried by a moving vehicle or person that uses the Global Positioning System (GPS) to track the device’s movements and determine its location. The recorded location data can either be stored within the tracking unit or transmitted to an Internet-connected device using the 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 smart phones with GPS capability.
GPS tracking unit architecture
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/CDMA/LTE modem to transmit this information to a central computer either via SMS or GPRS in the form of IP packets. Satellite based GPS tracking units will operate anywhere in the globe using satellite technology such as Global Star or Iridium and do not require a cellular connection.
Types
There are three types of GPS trackers, though most GPS-equipped phones can work in any of these modes depending on mobile applications installed:
Data loggers
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 tracked 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. In some private investigation cases, data loggers are used to keep track of a target vehicle.
Data pushers
Data pusher is the most common type of GPS tracking unit, used for asset tracking, personal tracking and vehicle tracking system. Also known as a GPS beacon, this kind of device pushes (i.e. "sends") the position of the device as well as other information like speed or altitude at regular intervals, to a determined server, that can store and instantly analyze the data.
A GPS navigation device and a mobile phone sit side-by-side in the same box, powered by the same battery. At regular intervals, the phone sends a text message via SMS or GPRS, containing the data from the GPS receiver.
Most 21st-century GPS trackers provide data "push" technology, enabling sophisticated GPS tracking in business environments.
Such GPS tracking systems are used by
- Automotive industry, for automatic vehicle location personal as well as commercial use.
- Law enforcement, for keeping track of arrested suspect out on bail or for persons subject to restraining order.
- Sports and Race control, where participants are kept track of their movements , speed, distance travelled as well as for cheating Espionage/surveillance, for tracking persons(by private investigators) or vehicle movements
- Aircraft tracking,
- Parents, to keep track of the movements of their children
- GPS personal tracking devices are used in the care of the elderly and vulnerable
- Monitor employees by companies, especially those in field work.
- Animal control, used by wildlife animal associations to study animal behaviour, migration patterns as well as on domestic animals to locate them in case they get lost.
Data pullers
GPS data pullers are also known as GPS transponders. Unlike data pushers that send the position of the devices at regular intervals (push technology), these devices are always on, and can be queried as often as required (pull technology). This technology is not in widespread use.
These can often be used in the case where the location of the tracker will only need to be known occasionally e.g. placed in property that may be stolen, or that does not have constant source of energy to send data on a regular basis, like freights or containers.