Definitions

GPS is a Global Navigation Satellite System, designed and supported by the United States. As this system, there are also others, although without the dissemination or extensive use of GPS, among them are:

• GLONASS, Russia
• GALILEO, Europe
• QZSS, Japan
• BEIDOU, China

How The GPS Works

The GPS is made up of three units.

Space

• Composed of satellites located about 20,200 km from the earth, distributed in 6 orbital planes
• Each satellite goes around the earth two times in one day
• The satellites run on solar energy, but they also have batteries in the event of an eclipse
• Therefore,  first satellite was flung into space in 1978

Control

The system is controlled by five tracking stations that are responsible for:

• Update orbital positions
• Calibrate and synchronize your clocks
• Determine orbits
• Plan trajectory

User

Therefore,  third unit of the Global Positioning System is that of the User, composed of the receivers of the radio signals emitted by the Space Unit’s satellites. These receivers should be used outdoors with a clear view of the sky.

These three units interact as follows:

• The satellite emits a signal called an ephemeris
• This signal identifies the satellite and the satellite time so that the user unit calculates its distance, taking into account its time. The satellite clock is atomic cesium and rubidium, while the receiver clock is quartz, which generates some inaccuracy.
• When the signals of several satellites are combined, it is possible to know the position, employing triangulation. Therefore,  signal from three satellites is necessary, which will give longitude, latitude, and altitude, with a precision of +/- 100 meters.

They complement the GPS

In addition to these three units, other units complement the system to give it greater precision:

DGPS (Differential GPS)

• It reduces the margin of error by using a ground station, which sends a signal that determines its fixed position.
• It differs from handheld receivers because they have the memory to store data, both from stationary and mobile units, and are calibrated to take data simultaneously.
• The ground data is then compared to the base station data for greater precision.

WASS (Wide Area Augmentation System)

• Satellite systems and ground stations provide corrections of the GPS signal, reducing the error margin to less than 3 meters.

Applications That Use GPS

The applicability given to GPS is broad. These are some fields in which the use of this system has become relevant.

Environment

It is possible to analyze environmental problems from a new angle based on the data collected thanks to GPS technology.

It is possible to do aerial studies of tight areas to evaluate flora and fauna or evaluate conservation efforts. Changes in the environment can analyzed.

Recreation

For lovers of outdoor activities, the information provided by GPS technology is extensive; It allows mountaineers to locate themselves through a map. It offers cyclists and runners information on their routes, and golfers use it to measure distances and improve their game. And also, You may interested in reading What to choose between handheld GPS, smartphone, or watch.

Disaster Relief

Therefore, Knowing where the disaster occurred allows the response time to shorter. In forest fires, it will enable locating the hottest areas so that they controlled first.

Topography and Cartography

Data collection times were reduced by changing the data collection method. Similarly, the costs of these processes were reduced as less equipment and personnel were required to do this work.

Others

Other applications using GPS are in the fields of Navigation (air, sea, and land), Agriculture, and Chronometry.

The GPS or Global Positioning System has impacted and improved various fields of the economy and recreation and currently widely used. Will the time ever come when this service is no longer free? That is one of the reasons why other countries have developed their satellite navigation system. And also, Time will tell.