Gps is the acronym for Global Positioning System, an expression that can be translated as Global Positioning System. Saying system was created by the Defense Department of the United States and allows, through a network of 24 satellites, to indicate the position of a body on the earth’s surface with great precision.
The trajectories of these 24 satellites, which orbit 20,200 kilometers above the Earth, are synchronized. In this way, coverage of the entire surface is achieved. The Gps uses the mathematical method known as trilateration to work with the information provided by satellites and thus determine the location of the object.
To know a position, the receiving equipment (also known as Gps) locates at least three satellites on the network, receiving signals from them that indicate the identification and the time. By calculating the time it takes for signals to get from the satellites to the equipment, the distance between the artifacts is measured. Then, with these distances already established, it is possible to determine the relative position of the object (that is, its coordinates).
Before continuing with the definition, it is important to note that many people confuse the concepts of trilateration and triangulation, although there are clear differences. The fundamental is that the second is based on the measurement of angles, something that in the first one does not happen at all.
Returning to trilateration, we must highlight the need to know the position of each of the twenty-four satellites at all times so that the GPS measurement is correct. In other words, if they could perform a journey random and constantly changing, then this technique would not work.
Let’s see step by step the process that takes place to calculate the position of a GPS receiver. First, one of the twenty-four satellites must send a message to the receiver to have a first distance to serve as a reference. Throughout the day, a maximum of eight satellites are known to be in each major zone off the ground, so we have plenty of test points.
Once the system decides which satellite gives you the right distance to reference, it’s time to move on to at least two more, although more can be used for more refined positioning. The idea is that by drawing an imaginary line between the GPS and the first satellite, we also obtain a sphere, which indicates all the points where the first could be located; Since there are infinite possibilities, we need more measurements to narrow down the search.
This system is not perfect, in that it does not yield results with one hundred percent of precision. For this reason, we must accept a margin of error of a few meters. As technology advances, this can be disguised with complementary techniques, but at the moment we are not talking about exact positioning.
The most common use of Gps is in the navigation, whether maritime, air or land. Many automobiles today incorporate a Gps so drivers can be easily located on a map. Also they cell phones (mobile) more modern usually include a Gps. Thanks to this service, we can travel a road unknown to us or find a point of interest in a city that we visit for the first time.
By allowing to know the location of vehicles or people, the Gps it is used for rescue tasks and for the search and recovery of automobiles, to name two examples. A Gps on the phone together with certain applications, on the other hand, it can be used to know where the user’s contacts are, showing the location on a base map.