GPS is a commonly-understood acronym that stands for “Global Positioning System,” which in turn is an interconnected system of satellites and receivers that allows for the precise pinpointing of locations anywhere on or directly above the earth. These sorts of systems have become very popular for everyday navigation, and many cars come with receivers installed to help drivers find their way to their locations. Maps applications on many smartphones also provide this sort of turn-by-turn guidance to help people get on the right streets and take the right exits. Beyond this more “standard” navigation, though, global positioning systems also have a big role when it comes to navigation on the ocean, deep in the forest, and in other largely “uncharted” areas. The mechanisms used to operate the GPS system as a whole are owned and operated by the United States Department of Defense, though they are free for anyone in the world to use. Just the same, several other countries and regions, in particular Russia, the European Union, and India, have or are in the process of creating their own unique systems, usually to complement the US version but potentially also to augment it and protect local users in the event of failure or other disabling of the services.
The heart of the system relies on 24 satellites that orbit the planet twice per day. Devices that are equipped with GPS equipment receive transmissions from at least a few of the satellites and are able to discern very precise positioning data. The first of these satellites was launched in 1974, and it wasn’t until 1994 that the 24th entered orbit. New satellites are periodically launched to replace aging ones.
Part of the reason why the system is operated by the US government is that its earliest uses were related to guiding military ships and vessels. It was created as an improvement to 1960s-era military navigational tools, and most iterations today rely at least in part on Internet connectivity. The early investments made by the armed forces when it came to developing and perfecting the system improved its efficiency to the point where it became cost-effective and practical to begin introducing civilian use applications. The first common use devices entered the market in the mid-1990s, but the system as a whole didn’t become a ubiquitous “household name” until the mid-2000s.
As the technology has improved, the cost of devices that include it has plummeted while the accuracy has increased. Small portable receivers have become very affordable, and the accuracy is usually quite good. Accuracy does vary based on a number of factors, but in most places a device will land a person quite close even if the directions aren’t perfect. Land-based supplemental devices can sometimes also be used to improve accuracy if higher precision is required.
Portable devices are used by fisherman and hikers to help them navigate in the wild. Many new cars are being equipped with satellite-based navigation systems to help drivers with getting from place to place, and it’s even used for tracking and hunting hobbies, like geocaching. In addition, many smartphones are able to access the technology, too, which can quite literally put advanced satellite navigation technology in a person’s pocket.
Though based in the US and operated by the US government and US-based space engineers, GPS systems are available, usually for free, all over the world. Even so, there are a number of other domestic and more localized options for people in different places. In Russia, for instance, the leading navigation system is known as Global Navigation Satellite System, or GLONASS, whereas the European Space Agency has championed an EU-specific equivalent known as Galileo. The Indian Regional Navigation Satellite System, or IRNSS, is expected to begin operations in 2016.