With a constellation of 32 satellites, global positioning system (of which GPS is the acronym) it provides accurate data to the centimeter – or most – of the position of objects, means of transport and persons.
Stands for Global Positioning System (in Italian of Global Positioning System), the GPS is a satellite positioning system that provides geographic and temporal information in all weather conditions. This system is capable of operating anywhere on Earth (and its vicinity), provided that there is a direct line of contact with four or more GPS satellites. The system was created and is maintained by the United States Government, but anyone – private citizens, commercial organization or government agency – can make use of its services if provided with appropriate signal receivers.
How does GPS
The GPS positioning system is based on a constellation of 32 satellites orbiting around the Earth at a distance of 26,000 km from the ground. So that we can receive the GPS coordinates, a receiver must be able to simultaneously capture the signal of at least 4 satellites, so you can make the so-called triangulation signal.
The calculation of the exact position has been entrusted, strange to say, a time-measuring system. The 32 satellites in orbit to Earth send radio signals with a frequency of 1575.42 MHz channeling information such as the time of sending and the position of the satellite at the time of transmission. The ground GPS receivers comparing the sending time with that of reception, so by calculating the shift of the satellite on an imaginary circle drawn on the earth’s surface in the course of its orbit. Crossing the data of at least three satellites, the GPS receiver is able to calculate the exact GPS coordinates, geolocalizzando the object or the person with an accuracy of a few meters.
The structure of the GPS
GPS is divided into three distinct segments: there is the space segment (space segment, SS), a control segment (control segment, CS) and the user segment (user segment, US).
The first segment includes 32 satellites in orbit; the second includes all land-based monitoring tools, which enable the maintenance in orbit of the first segment and the operation of the entire detection system; the third, finally, includes the millions of users – military, commercial and civilian – who daily access the system with their GPS receiver.
The GPS system was born between 1960 and 1970 to respond to the needs of the US armed forces – Army, Navy and Avizione – to have a positioning system effective and functional. Since its introduction, however, the system has never been used exclusively for military purposes, but has found application in various fields.
In the civil field, for example, it can be used to make cars capable of moving in traffic, without the need for a driver that the lead. GPS receivers are widely used in the field of geolocation: using the satellite system created by the US Government, you can move by car, bike or even walk without fear of getting lost down the street or do not arrive on time. But GPS is now an integral part of most – if not all – of the models smartphone on the market today. Thanks to geolocation, these mobile devices are able to offer services unimaginable until a few years ago: you can know exactly when the next bus, you can geotag (add the GPS coordinates) photos and movies, you can sync with accuracy of the system clock and avoid mismatches with the various cell phone where you connect and more.
In commercial matters, however, it has become an essential travel companion and mandatory for naval convoys ocean, which can base their routes also on the movements of other trains in their vicinity. The GPS, however, can also be used to track the movement of goods from one port of call (or airport) to the other and verify that the shipment is in order.
The global positioning system, however, retains its high military value: thanks to GPS troops can move without too many problems even in the dark or in enemy territory, allowing them to circumvent or avoid natural obstacles of running into enemy positions. The GPS also has a key role in tracking and guidance system of so-called smart missiles: once you have entered GPS coordinates, these weapons can reach targets hundreds of kilometers away without the need of a support aircraft.
As seen, this positioning system ensures undoubted advantages, both from a commercial point of view and from a strictly subjective point of view. At the same time, they are undeniable risks to privacy related to overuse of GPS receivers.
Whether you use the GPS receiver of your smartphone or the car, you end up always be traceable. And not only from loved ones or acquaintances, but also by people who, maybe, want to somehow find out how we move and what places we frequent most often.