Today, artificial Earth satellites are actively used in many areas of our lives. Satellite television and satellite Internet are no longer new. The GPS satellite navigation system also becomes familiar. What kind of system is this, and what tasks does it solve?
Operating principle
First, let's figure out what GPS is. This abbreviation comes from the English words Global Positioning System - a global positioning system. This is the name of the space satellite system, which began to be developed back in the 1970s by order of the US military. In the 80s, civilians were allowed to use it. GPS helps you determine the exact location and coordinates of a moving object. Satellites are not affected by weather conditions, so the system operates around the clock.
The main advantage of this system is its free. In order to learn and experience what GPS is, you only need to purchase a special receiver and software. The latter is an electronic map of the region in which you are located, as well as the A-GPS program, which is used in cloudy weather. It connects to a special server, which contains information on the coordinates of the nearest satellites. Today, this program is in every car navigator.
How is GPS navigation done? 24 satellites move in circular orbits, each of which makes 2 revolutions per day and transmits radio signals. By accepting them, the GPS receiver calculates its location. First, the difference between the time of the signal and the time of reception is calculated. This calculates the distance to the satellite. If there are at least two of those in the receiver’s area, then it can determine the latitude and longitude at which it is located, and mark itself on an electronic map. When capturing four or more satellites, the receiver software calculates not only the latitude and longitude, but also the speed of the object, the distance traveled and the remaining distance, the time of sunrise and sunset, and many other values. The accuracy of determining the coordinates of GPS-receivers today is from 5 to 20 m (in height - up to 10 m).
Application area
So, what is GPS, we learned. In what areas can this system be applied? In almost all.
Let's start with the most common and known to the wide user. These are car navigators. In fact, these are computers for which a special operating system is used. They already have installed navigation software that cannot be changed without violating the license. In addition to navigating in urban space, navigators provide a host of additional features - you can use them to view photos, play music, watch videos, and connect to the Internet.
Car navigators are actively used not only by ordinary motorists, but also transport companies. After all, the GPS system allows you to monitor the route of vehicles with cargo and quickly respond to possible delays. With a special sensor, this system can also monitor fuel consumption.
Another area of application is pedestrian navigation. There are compact navigators that can be used for hiking and hiking. They are a good alternative to the usual map and compass. Also, navigators can be built into mobile devices - smartphones. The accuracy of the coordinates in this case is still lower than that of conventional receivers, but manufacturers are actively working on the development of navigation programs.
Speaking about what GPS is, one cannot but recall the disadvantages of this system. The quality of signal reception is affected by urban density, the presence of trees with dense foliage, ground-based sources of radio signals and other factors that create interference. But the main problem is the dependence of satellites on the will of the US military. There is no guarantee that at one point it will not turn on the interference or simply not turn off the civilian sector in any region. Fortunately, alternative navigation systems already exist that do not “get lost” in this case. These are Russian GLONASS and European Galileo. Manufacturers of navigators are also preparing for such emergency situations and are developing chips that can support all three navigation systems.