GPS

The position of the collared animal is estimated by the GPS engine inside the GPS collar. GPS fix location data is stored on board of the GPS receiver. Modern GPS tracking collars are able to send such GPS position data from the object directly to a receiving station. There are differnt possibilities of that remote fix data transmission.

Via VHF or UHF cummunication link, via satellite communication or via the GSM.

A receiving station can be a stationary receiver of a tracking service company (in case of car tracking f. ex.), a provider of a mobile phone company, or just a PC. Nowadays the GPS location data can be also received by small mobile gadgets like laptops, handsets etc.. and are multiplicators.

The Global Positioning System consists of a set of 24 operational satellites and land-based control stations. The system was designed for and is operated by the U. S. military, owned by the US Department of Defense (DoD). But it is available on a worldwide basis to all civil GPS users with no direct charge.

GPS determines distance between a GPS satellite and a GPS receiver by measuring the amount of time it takes a radio signal to travel from the satellite to the receiver. Radio waves travel at the speed of light, which is about 300,000 kilometers per second. So, if the amount of time it takes the signal to travel from the satellite to the receiver is known, the distance from the satellite to the receiver (distance = speed x time) can be determined. If the exact time when the signal was transmitted and when it was received is known, the signal's travel time can be determined.