To solve a wide variety of military and civilian tasks, it is often required to accurately determine the coordinates of a place and the current time. Modern technologies have made it possible to create a number of satellite systems that make it possible to successfully achieve such goals. The most famous satellite navigation systems today are GPS and GLONASS.
The first attempts to develop a satellite navigation system date back to the late 1950s. The idea was simple and clear: by the position of an artificial satellite and its speed, it is quite possible to determine the own coordinates and speed of an object on the Earth's surface. But the technology allowed to actually start implementing this idea only after two decades. From 1974 to 1993, the United States of America launched 24 satellites into low-Earth orbit, which made it possible to fully cover the entire planet. The main purpose of the created navigation system, called GPS (global positioning system), was, of course, military. The complex of satellite and ground equipment gave the American military the ability to accurately target missiles to mobile and stationary ground and air targets. The Soviet Union began to create a GPS analog much later. The first near-earth object of this global navigation satellite system (GLONASS) was launched into orbit in 1982, and the Russian constellation of satellites was brought up to the standard number in 1995. The principle of operation of GPS and GLONASS is the same. The signal emitted from the satellites is sent to a device installed on the ground, such as your car's navigator. The receiver determines the distance to each of the satellites included in the navigation system (at least four of them are required to determine the coordinates of the object). After automatic comparisons and calculations, the receiver gives the exact time and coordinates of your location. As for the differences between GLONASS and GPS, experts attribute the fact that domestic satellites are not synchronized with the rotation of the planet to the unique advantages of the Russian system. This feature gives the system better stability; there is no need to additionally correct the position of each of the objects of the space constellation. The disadvantages of GLONASS include a shorter satellite service life and a lower accuracy in determining geographic coordinates in comparison with its American counterpart. The purpose of GLONASS is not limited to military purposes only. Navigation support assumes gratuitous provision of access to civil signals of the system for both Russian and foreign consumers. Portable navigators are becoming loyal and indispensable helpers for motorists, tourists, hunters and fishermen.
