How Glonass and GPS work. Which is better - GPS or Glonass
Without a developed telecommunications sector, imagine modern world is no longer possible. How can you not force people to use kerosene lamps, when there is electric lighting around, you can’t force them to stop using the Internet, satellite TV and navigators. In this article we will look at some issues related to satellite systems global positioning, used for navigators, including car GPS and GLONASS. As a result, having learned a little about each of these systems, you can choose the best alternative for yourself when buying a car navigator.
About GPS and GLONASS satellite positioning systems
Although the era of the Great geographical discoveries long gone, however, the problem of accurately determining the geographical coordinates of an object, moving or stationary, was a complex mathematical problem with many unknowns. Development of the space industry, wide application artificial Earth satellites, first to transmit simple text information, then more and more complex and large information arrays, prompted scientists to develop systems for determining the ground coordinates of objects using artificial Earth satellites. Of course, the solution to this problem was not trivial. But here I came to the rescue computer technology, which has greatly accelerated the processes of calculating and taking into account many parameters when determining the geographical coordinates of objects. The first customers of such systems were the military - where would we be without them? They had to know exactly the location, first only of nuclear facilities, both enemy and friendly, missile-carrying aircraft, nuclear submarines, and now it has come to determining the location of each soldier on the battlefield.
But this state of affairs could not last long, and already in the new millennium the military was forced to open the systems for civilian use. Very quickly, household navigators were developed, including car navigators, which show your position in a particular place with sufficient accuracy globe. But it must be said right away that the accuracy and determination of coordinates of the positioning systems used in the civilian and military sectors differ, and quite strongly.
Global positioning systems have found application in logistics, giving rise to a new direction – telematics. The second area is global emergency warning systems. In addition, positioning systems are extremely important in geodesy, cartography, land management and other industries. Well household use- these are navigators that can be used not only in a car, but also simply while moving around on foot. unfamiliar city etc.
At the moment, several global positioning systems have been developed. But three of them can be distinguished: the American GPS, the Russian GLONASS, and the European Galileo. In addition, China and India are also developing their positioning systems so as not to depend on the Americans, who can reduce the accuracy of identifying an object, or even turn off the broadcast of signals in certain areas. There have already been precedents.
About the GPS system for navigators
GPS stands for Global Positioning System, or in Russian - global positioning system. Like any positioning system, GPS consists of a space segment, which currently consists of more than thirty satellites, a system of ground-based command complexes that control the space segment, and, in fact, receivers located at consumers.
We will not go into technical details of the functioning of the systems, but will simply talk about general concepts. The satellites rotate in six planes, at a distance from the Earth's surface of approximately 20,000 km. Satellites broadcast two types of signals: C/A-code, this is a public signal, and P-code, a protected code. The P-code is approximately 10 times more accurate than the publicly available signal. Access to a signal with a P-code can be provided by the US military department. This code has high degree encryption, so no one will reveal the code in vain.
How GPS works
The satellites included in the system constantly emit a signal to the earth's surface. To determine the point of his location, the navigator needs to calculate three coordinates and take into account the difference in time scales of both the satellite and the navigator. Typically, signals from four satellites are used to compensate for errors, although signals from more satellites. Having captured the satellite signal, the navigator extracts the C\A sequence from it, compares it with its parameters and builds a three-dimensional picture of the satellites. In this case, constant synchronization of the signal from the satellite is necessary. The accuracy of the measurement also depends on the location of the satellites from which the signal is received. If, for example, they are all located in the northern and western segments, then it will be impossible to build a correct triangulation (a network of geodetic reference points).
About the GLONASS system for navigators
Unfortunately, the times of perestroika and transition to a new economic formation delayed the development of such a system in our country. In general, we are currently lagging behind in the development of the system. There are fewer satellites in the space segment, software The microprocessors that perform the calculations are also not the most advanced. And besides, the moment was missed when the market demanded navigators, but our industry was unable to provide them to consumers. That’s why the phrase “Geepies Navigator” is used, not Glonass Navigator.
Glonass satellites emit two frequencies. One is called the standard precision frequency, the second is the high precision frequency. As you yourself understand, the second frequency serves the needs of the military and intelligence services. The principle of operation of the system is the same, so we will not repeat it.
GLONASS provides the following parameters: - accuracy in horizontal coordinates is 50-70 meters - accuracy in vertical coordinates is 70 meters - determination of the motion vector up to 15 cm/s Of course, these are maximum error indicators. At favorable conditions, they can be 2-3 times better. The indicators are no worse than the American ones. For example, in GPS, the error in coordinate accuracy can reach 100 m. Satellites are located in three planes, at an angle of 120 degrees. Americans have 6 planes, with a shift of 60 degrees. GLONASS is more effective in high latitudes, where most of our country is located, GPS - in mid-latitudes. Everyone created a system for themselves.
Which navigator is better GPS or GLONASS?
The main thing that hinders the development and spread of GLONASS navigators is weak cartographic support. Without clear, correctly drawn maps, a navigator is a useless toy. Unfortunately, cartographic support has always been the prerogative of the military, and was often shrouded in secrecy. Now we are paying for it. Of course, there are some exceptions, but the bulk of the country's territory should be accessible on maps for civilian navigators. At the moment this is the most a big problem for GLONASS navigators, which hinders their implementation for civilians and makes them less attractive for general use. We can only “look to the future” with hope, and hope that even the civilian population of our country will not depend on the well-coordinated work of American satellites.
(GLONASS) in funds mass media Recently, quite a lot of attention has been paid, and the average person, especially one who is far from the problems of satellite navigation, may get the impression that this system has appeared quite recently and is in its infancy. In fact, this is absolutely not true. And yet, what is GLONASS? When did it appear and what is better than the famous GPS?
History of the emergence of domestic satellite navigation
The idea of using it for navigation needs appeared back in the fifties of the last century, when the first object created by human hands ended up in low-Earth orbit. It was then, observing the signals of the first satellite, that scientists became convinced in practice that the frequency of the signal received from a satellite in orbit varies depending on its position relative to the observer. In addition, knowing the exact coordinates of the observer on Earth, it is possible to measure the coordinates and speed of the satellite and , respectively, vice versa. The Americans implemented this idea in 1974, when the first navigation satellite was launched under the DNSS program (later the program became known as Navstar-GPS, and then simply GPS).
But what about the homeland of astronautics? Soviet scientists did not sit idle at this time either. Even before the world knew what GLONASS or GPS was, the first navigation satellite “Cosmos-192” was launched in 1967, and in 1968 “Cosmos-220”. Both satellites were intended for the needs of navigation and providing long-distance communications for ships of the Soviet Navy and were part of the first navigation system “Cyclone” (in the civilian version - “Cicada”). And in 1976, the system, which included 6 Parus spacecraft, was already put into service. The accuracy of determining the coordinates was 80-100 m, which for that time was not so bad.
Around the same time, it became known what GLONASS is. In 1976, in continuation of the Cyclone program, the Central Committee of the CPSU and the Council of Ministers of the USSR issued a special resolution on further development domestic satellite navigation. Despite the constantly shifting deadlines, in October 1982 the first Uragan satellite, belonging to the GLONASS system, was launched into orbit, and by 1991 there were already 12 operational satellites in orbit.
The official commissioning of the system took place in September 1993, and by 1995 the satellite group consisted of 24 satellites (standard number). Unfortunately, the restructuring, subsequent and limited satellites led to the fact that by 2001 there were only 6 working satellites in orbit, and they began to slowly forget about what GLONASS is.
After the adoption of the federal program in 2001, the situation began to improve, and by the end of 2011, the number of satellites was brought to the required level. For the period 2012 -2020. 320 billion rubles have been allocated for the development of GLONASS. During this time, it is planned to manufacture and launch another 22 GLONASS-K and 15 GLONASS-M satellites.
How GLONASS works
The principle of operation of the domestic one is the same as that of the American GPS. Satellites in orbit continuously emit two types of signals - standard and high precision, which are available to consumers located almost anywhere on the planet. To determine exact coordinates, only appropriate GLONASS equipment is required.
Despite the fact that the accuracy of determining coordinates using the domestic system is somewhat inferior to the American one (3-6 m versus 2-4 m) and the service life of the satellites is shorter, GLONASS provides greater stability due to the fact that it does not depend on the rotation of the Earth and, therefore, does not require any additional adjustments. If we talk about accuracy, by 2020 the developers plan to increase it to 0.6 m, and in the future - to 0.1 m.
As for receiving equipment, GLONASS navigators integrated with smartphones are now installed in regular phones. Modern hybrid devices that can work simultaneously with GLONASS and GPS can now be freely purchased in stores selling consumer electronics or ordered from an online store.
While the European Union, India, China and other countries are only at the initial stage of developing satellite navigation systems, the United States and Russia have long been using outer space for these purposes and willingly provide their services all over the world. GPS (Global Position System) and GLONASS (Global Navigation Satellite System) - so far only they transmit information to us from space, and therefore a reasonable question arises about their comparison.
Not competitors, but comrades-in-arms?
In the initial story practical application satellite monitoring, both Americans and Russians (at that time still citizens of the USSR) managed to have their say. The first satellite was launched by the Russians, the first monitoring was carried out by the Americans - and so, one after another, without any special breaks, satellite tracking systems appeared and developed in parallel and almost symmetrically. Both of them work on the same principle - several dozen satellites located in low-Earth orbit on different planes transmit signals to receiver devices, and these signals can be used to obtain coordinates, speed and other data. This helps to monitor vehicles of any type (including underwater) and provides personal tracking capabilities.
Shoulder to shoulder
What is the current situation with these systems? They are equally actively used throughout the world and have equal privileges. Any company that sells satellite navigation systems will not give preference to one of them, but will offer both options or combined devices with both systems in one set. But the “Russian” had all the prerequisites not only to fall behind, but also to cease to exist altogether when, due to the difficult economic situation associated with the collapse of the USSR, funding for developments ceased. These were difficult years for GLONASS, and it lagged significantly behind in development, but within a few years, with the help of money and bright minds, it was possible to catch up. And this is despite the fact that other countries still continue to stagnate in the initial stages of development of satellite monitoring systems.
Who is more accurate?
Since the launch of GLONASS satellites was suspended for some time, long years this system was quite behind GPS. Therefore, when the number of satellites in orbit for both systems was almost equal, many foreign consumers using GLONASS began to consider the latest development, without even knowing about the period of stagnation. Today there is a slight gap in the number of launched satellites in favor of GPS, which will soon be closed thanks to active funding for the development of GLONASS. As for the interface and other user functions, both systems have the same, understandable and accessible control principles.
Now many of us cannot imagine our lives without any devices that were born with the help of latest technologies. A striking example is all kinds of gadgets designed to calculate location. They can be anti-theft devices, portable navigators or even entire tracking systems. They all have a number of features and differ from each other in their set of functions.
But the most important difference, which a potential buyer most often pays attention to, is the accuracy of determining the location coordinates.
All devices of this type can be divided into three groups depending on the technology that is used in their operation - GPS, GPRS and GLONASS. Each type of device has a number of advantages and disadvantages.
Enough already for a long time There are disputes among satellite system enthusiasts. Some believe that Russian system GLONASS is the pinnacle of perfection, while others are confident that at the moment there is no technology that can compete with GPS. Is it so?
To give the correct answer to this question, it is necessary to delve a little deeper into history. The technology for determining location using satellites is the Doppler effect, which is known to every person from a high school physics course. The bottom line is that the frequency of a satellite's signal depends on the distance at which it is located from the Earth.
Do not forget that the GLONASS system is much younger than GPS. This is confirmed by historical dates. At the time of the launch of the first navigation system, there was an eight-year gap between GPS and GLONASS. However, our scientists and engineers have done a tremendous amount of work, so currently both systems are direct competitors. At the moment, the error in determining the location coordinates of Glonass is slightly greater than that of GPS. However, representatives of the domestic company promise that by 2020 they will be able to catch up and overtake GPS in many respects.
What is the difference between GPS and GLONASS?
Devices operating using the GPS system are very picky about the presence of active satellites. To determine the coordinates as accurately as possible, the device must pick up signals from six to eleven. But for the Glonass navigator, it is enough to have six or seven active satellites to determine the location with the same error.
What is more accurate: GLONASS or GPS? Don’t forget about those devices that have both systems on board. Their performance is one of the best. Such “double” devices cost a little more than regular ones, so to increase efficiency it is best to purchase them.
What is the difference between GPS and GPRS? There is another technology that makes it possible to determine location. It is called GPRS. This abbreviation is well known to all users. mobile internet, because it was with its help that until recently access to the World Wide Web was achieved.
The main difference between these two systems is that GPS receives signals from satellites, and GPRS uses Internet access. That is why beacons that use only GPRS technology for detection often provide data with a large error. It is also worth noting that such tracking systems are imperfect, as they often end up in coverage areas.
For increased safety, use GPS. Its cost is not very different, but the level of efficiency is an order of magnitude higher. gprs technology has taken root very well in GPS systems GLONASS. That is, the device receives location data using three technologies at once, which significantly reduces the error.
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