GPS is an acronym that stands for Global Positioning System. GPS is one of a few satellite navigational systems, however it is the only fully functional system currently in service. GPS consists of more than 2 dozen global positioning satellites orbiting the earth. Each satellite transmits radio signals which can be received by GPS receivers to determine location, speed and direction.


GPS was first introduced in 1978, but was only in its experimental stages due to the few satellites that orbited the earth. However, ever since its launch, it has been an extremely important, practical and indispensable technology. The maintenance of GPS is not cheap; it usually costs upwards of 400 million dollars to keep GPS up and running each year. It should be noted that GPS is a free service offered for the public good.

How GPS Works
In order for GPS tracking to work, it is necessary to have both access to the Global Positioning System and have a GPS receiver. The GPS receiver is able to receive signals that are transmitted by GPS satellites orbiting over head. Once these satellite transmissions are received by the GPS receiver, location and other information such as speed and direction can be calculated.

A GPS receiver needs to receive transmissions from at least three or more GPS satellites to calculate its position effectively. GPS receivers usually measure the time delays between the transmission and reception of each of the satellites GPS radio signal. This technique of calculating distance using three separate transmissions is called trilateration.

GPS Tracking
GPS Tracking is a term used to determine the location of a person, vehicle or any other asset using the Global Positioning System. Usually the location of the object is recorded at regular intervals. Recording of an object can take place within the GPS receiver unit, or can be transmitted to a central location such as a database, where it can be accessed either via mobile phone technology or over the internet with the use of a computer. GPS tracking units can use cellular GPRS, satellite modem technology or radio waves to transmit the information to the central location where the data is logged and recorded. Usually most GPS tracking systems can be viewed in real time and have a map in the background to easily display the current location of an object.

Three Types of GPS Tracking Units
There are currently three categories of GPS tracking units. The categories are split into how GPS data is logged and retrieved.

Data Loggers
Data loggers are usually the most basic type of GPS tracking; a GPS data logger simply logs the position of the object at regular intervals and retains it in an internal memory. Usually, GPS loggers have flash memory on board to record data that is logged. The flash memory can then be transferred and accessed using USB or accessed on the device itself. Usually data loggers are devices used for sports and hobby activities. They might include devices that help log location for hikers, bikers and joggers.

Data Pushers
Data Pushers are GPS tracking units that are mainly used for security purposes. A data pusher GPS tracking unit sends data from the device to a central database at regular intervals, updating location, direction, speed and distance.

Data pushers are common in fleet control to manage trucks and other vehicles. For instance, delivery vehicles can be located instantly and their progress can be tracked. Other uses include the ability to track valuable assets. If valuable goods are being transported or even if they reside in a specific location, they can constantly be monitored to avoid theft.

Data pushers are also common for espionage type tasks. It is extremely easy to watch the movements of an individual or valuable asset. This particular use of GPS tracking has become an important issue in the field of GPS tracking, because of its potential for abuse.

Data Pullers
The last category of GPS tracking units is the data pusher units. These types of units push data or send data when the unit reach a specific location or at specific intervals. These GPS units are usually always on and constantly monitoring their location. Most, if not all data puller unit also allow data pushing (the ability to query a location and other data from a GPS tracking unit).