GLOBAL POSITIONING SYSTEM (GPS)

The Global Positioning System (GPS) is a technical marvel made possible by a group of satellites in Earth's orbit that transmit precise signals, allowing GPS receivers to calculate and display accurate location, speed and time information to the user.

By capturing the signals from three or more satellites (among a constellation of 31 satellites available), GPS receivers are able to triangulate data and pinpoint your location.

With the addition of computing power and data stored in memory such as road maps, points of interest, topographic information and much more, GPS receivers are able to convert location, speed and time information into a useful display format.

GPS was originally created by the United States Department of Defense (DOD) as a military application. The system has been active since the early 1980s but began to become useful to civilians in the late 1990s. Consumer GPS has since become a multi-billion dollar industry with a wide array of products, services, and internet-based utilities.

GPS works accurately in all weather conditions, day or night, around the clock and around the globe. There is no subscription fee for use of GPS signals. GPS signals may be blocked by dense forest, canyon walls, or skyscrapers, and they don’t penetrate indoor spaces well, so some locations may not permit accurate GPS navigation.

GPS receivers are generally accurate within 15 meters, and newer models that use Wide Area Augmentation System (WAAS) signals are accurate within three meters.

While the U.S. owned and operated GPS is currently the only active system, five other satellite-based global navigation systems are being developed by individual nations and by multi-nation consortium's
 How the Global Positioning System functions is based on the relationship between GPS satellites and GPS receivers (read: GPS-enabled devices). According to Garmin, a GPS technology company, the Global Positioning System works when GPS satellites transmit "a unique signal and orbital parameters that allow GPS devices to decode and compute the precise location of the satellite."

From this transmission, GPS receiver devices are able to calculate the location of their users by measuring the "the distance to each satellite by the amount of time it takes to receive a transmitted signal" and then combining that with the distance measurements from several other satellites.

 And so, in order to correctly calculate a person's "2-D position", which is just latitude and longitude, a given GPS receiver device would need to receive a signal from at least three satellites. Calculating a 3-D position, on the other hand, would also add in altitude and require the signal of at least four satellites. Usually, according to Garmin, most GPS receiver devices will receive and track the signals of at least eight satellites, but this number can vary based on your location and what time it is.
 GPS isn't just for navigating your way home. There are many other everyday uses for GPS. Here are a few examples:

Geocaching

Geocaching is a form of recreation that involves setting up treasure hunts; hiding "treasures" (usually small prizes and toys) in certain locations, then uploading maps online to have other people search for them with GPS devices (like smartphones or more expensive GPS units).

Child Safety

These days parents and schools are making use of GPS via wearables and mobiles with built-in location trackers to keep track of their child's location. Now, if your child gets separated from their class during a field trip, it's a lot easier to find them.

Electricity Access

You local power company probably uses GPS to keep track of power outages and their repairs. The use of GPS can help these companies quickly figure out where an outage is, and where and if repairmen are nearby to fix it.

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Movies

Cinematography hasn't been the same since GPS became widely available for consumer use. Now, GPS is used for things like location scouting, to help find the best places to film certain movies. GPS can also be found in those big, sweeping, birds-eye-view camera shots in your favorite movies, because it's likely a GPS-controlled drone was used to film it.