A GPS tracking unit is a device which uses global positioning systems in determining the specific position or location of a person, vehicle or any other asset. The device is usually attached to the person or vehicle to be tracked and the position is recorded at determined intervals.
The recorded data is then stored in the unit or is transmitted to a central location or to a computer that is connected to the internet using GPRS of Text Messages, satellite modem or radio. This enables you to see the location of whatever thing you are tracking either in real time or as you analyze the track at a later date.
GPS tracking unit design
The tracker unit usually contains the GPS module which receives GPS signals and calculates the coordinates. The tracker also contains data loggers which have a large memory that is used to store the coordinates.
Data pushers also contain GPRS or GSM modems which transmit information to a centralized computer either through SMS or GPRS in the form of IP packets.
Types of GPS tracking units
GPS tracking units fall into three categories namely Data loggers, Data pushers and Data pullers. Almost all Smartphones work in all the models depending on the applications installed.
Data loggers
They basically log the device’s position at specified intervals in its memory. Modern loggers have a memory card slot or a flash memory and a port for USB. Some may be used as USB flash drives which enables downloading of the log data for further analysis in a computer. The track list may be in KML, GPX or NMEA formats.
A majority of digital cameras save the exact time a photo was shot. If the camera’s clock used the GPS as its source or time then the time may be correlated with GPS log data hence giving an accurate location. This may be added to the Exif metadata in the picture’s file.
In various cases of private investigations data loggers may be used in tracking a targeted vehicle. The investigator has to follow the target closely and have a data backup source.
Data pushers
These are the commonest of all tracking units and are used mainly for asset tracking and vehicle tracking systems. They are also called GPS beacons, and they work by pushing the device’s position as well as other necessary information such as altitude or speed at regular intervals to a set server. The server then stores the data and starts analyzing the data immediately.
A GPS navigation device is put side by side with a mobile phone in one box, using one battery. The phone sends an SMS or GPRS at regular intervals containing data from the receiver. Most GPS trackers in the 21st Century provide data push technology which enables sophisticated tracking in business premises, organizations and commercial fleets.
Data pullers
They are also called transponders and unlike the data pushers, they are always on and may be queried as often as needed. This technology has not been widely in use, but a good example is a computer to the internet and also running a gpsd. They can be used in occasions where the tracker only needs to be known once in a while.
Data pullers are now being used in the form of devices with GPS receivers and cell phones that when they receive an SMS they reply with a message containing their location. You can read more about the GPS Units at http://gurtam.com/en/
Very informative article. The GPS technology is advancing rapidly more than we can keep on it. Today, we can track almost anything or anyone!