What is the difference between GPS and Glonass. Global Satellite Navigation Systems

M (competitors of the American GPS system), which were launched on December 5 of this year from the Baikonur Cosmodrome, a few hours later fell in the Pacific Ocean, northwest of Honolulu, without reaching orbit, attracted the attention of the general public.

What are the differences between the main global navigation systems that currently exist? Autoportal correspondents looked into this issue.

First, about the Russian development, which recently appeared in the reports of world news agencies.
GLONASS (Global Navigation Satellite System) - Russian system satellite navigation. In fact, this is a group of special-purpose satellites. From near-Earth orbits, they transmit signals from which the navigation device calculates its coordinates on the ground. They are then displayed as a pin on the map.

The project was launched back in Soviet times: the first satellite was launched into orbit in 1982. Initially, the system was planned to be used exclusively for defense needs - for ordinary citizens accurate navigation was not available locally

The well-known GPS (Global Positioning System) orientation system, which has been used around the world for a relatively long time, was created and financed by the US Department of Defense. Its signal has become available since 2000, and today the number of models of navigation devices that work with it is innumerable.

The main difference is the signal and its structure. The GPS system uses code division. In the GLONASS system - frequency division channels.

To describe the motion of satellites in orbit, fundamentally different mathematical models. The GPS model implies that the satellite's trajectory is divided into sections.

The GLONASS system uses a differential motion model. This means that to determine the satellite coordinates for this moment It takes time to solve a system of differential equations.

The GPS system has 6 orbital planes, and was supposed to have 4 satellites on each. Total - 24 satellites, but they did not provide adequate coverage of the entire globe, and if any device fails, then there is nothing to replace it with. Therefore, the constellation was increased to 32 satellites. In this case, some orbits have up to 6 satellites.

The GLONASS system has 3 planes with 8 satellites each (8 theoretically). This ensures complete ground coverage and good geometry. The Russians calculated a more optimal orbit, but they were unable to complete everything as a whole.

Due to serious technical error, at the beginning of December this year, the Proton-M launch vehicle carrying 3 GLONASS-M satellite veered 8 degrees off course, causing the satellites to enter an open orbit and fall in an unnavigable area of ​​the Pacific Ocean.

Areas of application

Satellite navigation has GPS, unlike Russian analogue In addition to popular navigation systems, new areas of application are constantly emerging. Take, for example, the so-called trackers. This is a miniature device that can be placed in a schoolchild's briefcase, tied to a dog's collar, or hidden in a car first aid kit. After that, on the website special service You can see on the map at any time where the tracker and, therefore, the object itself are located. Or you can set a zone, and when the tracker goes beyond its limits, you will be notified by an SMS message.
The device can be equipped with a panic button. One click from someone in trouble and an “SOS” signal goes on the air. The one who receives it can determine from the map exactly where the incident happened.

Difference in resources

IN existing form the GLONASS system was developed and launched in the interests of the Russian Ministry of Defense in 1993 with a limited orbital constellation (12 satellites). In 1995, the orbital group was expanded to a staff of 24 spacecraft, but was subsequently reduced again due to underfunding. Before the above-mentioned incident with Russian satellites, there were 26 GLONASS satellites in Earth orbit, but only 20 are in use, 4 more were temporarily taken out of service, and 2 were in reserve

The average technical resource of GLONASS satellites is 4.5 years with a guaranteed active life of 3 years.

The United States uses second-generation GPSIIR satellites with a technical service life of 10 years, in reality - up to 20 years, which allows them to have the entire constellation of satellites in orbit necessary for the system to function and to maintain its operation by launching just one satellite per year. The accuracy characteristics of the Russian GLONASS are also significantly inferior to the American GPS. The standard deviation of GLONASS in the plane is 17.1 m, in height - 22.18 m, and GPS has similar indicators - 2.76 m and 7.51 m. In addition, RussiansI still can'tgutprovide GLONASS coverage throughoutplannedterritories

To answer this question, let's delve into history.

GLONASS (global navigation satellite system)– developed primarily to increase the defense capability of the USSR, and then Russia, and was put into operation on September 24, 1993. The accuracy of the civil signal, without the use of differentiated correction systems, is currently 3-6 meters; in the coming 2015 it is planned to increase it to 1.4 meters. Since 2008, the word “GLONASS” has become familiar to everyone. Dmitry Medvedev, then president Russian Federation, signed the federal law“On navigation activities” and laid the foundation for global projects such as “ERA-GLONASS”, intelligent transport systems and others. At the moment, the GLONASS satellite system includes 24 satellites and covers the entire territory of our planet.

GPS (Global Positioning System - global positioning system)– developed and operated by the US Department of Defense. Initially, this was a purely military project, but the tragic events on Sakhalin (in 1983, a Soviet fighter shot down a Korean plane with 269 passengers on board) forced President Reagan to reconsider the matter. The only thing is that scientists have created an algorithm that worsens the accuracy satellite signal for civilians. In 2000, President Clinton abolished signal correction, which gave an incredible impetus to development huge amount industries. Satellite signals began to be used for construction work, Agriculture, transport logistics and much more. Modern people can't imagine life without a companion. At the moment, the GPS satellite system includes 29 satellites, this makes it possible to obtain accuracy of 3-5 meters without applying differentiated corrections.

Now let's get back to the question “Which is better?”. If you take only specifications, then objectively GPS gives more high quality signal reception. But there is one BUT. Almost all navigation modules installed in all portable devices: Cell phones, navigators, trackers use multi-system receivers. Those. they receive signals from both the American and Russian satellite systems simultaneously. GLONASS/GPS modules.

Those. simultaneously, modern receivers can receive 18-20 satellites, instead of 9-10 previously (when only GPS modules). This improves the quality of the signal, thereby reducing the error and practically reducing the possibility of error to 0. But this is not the limit, in the near future the European and Chinese satellite systems will be fully put into operation: Galileo and BEIDOU (compass). Now we will all be able to receive a free signal with centimeter accuracy and with the development of ground-based base stations it will give an unprecedented leap in the development of technologies for all areas our lives, for example, autopilot systems.

Video review:

How GPS and GLONASS navigation systems work

The abbreviation GLONASS literally stands for “Global Navigation Satellite System”. This system satellite navigation is Russian. It was developed by order of the USSR Ministry of Defense and began working in the 50s of the last century, at the time when the first satellite was launched into space. While studying satellite signals, scientists discovered that when using them in a special way, it is possible to determine your location by coordinates, with very high accuracy for that time. This discovery was followed by active scientific works with the aim of developing a global navigation satellite system.

For the first time, GLONASS entered Earth orbit only in 1982. In the 90s, this system already had full set satellites, in the amount of 24 pieces. However, funding for the system soon ceased and by 2001 only 6 satellites remained. Today in Russia there is a federal target program to completely modernize the configuration of this system and restore the number of satellites in orbit.

Satellites of the GLONASS system move along 8 satellites in 3 planes. Their trajectory is not synchronized with rotation Globe. Thanks to this movement, the satellites are more stable and do not need to be adjusted. But there is also a significant disadvantage - their service life is quite short, and their quantity is not yet sufficient for maximum use of the system.

The signal is transmitted over the FDMA frequency and a complex calculation model is applied at the coordinate receiver. This model is very resource intensive for the receiving device, as a result of which they have more powerful processor and receiver, and this leads to an increase in their dimensions.

The letters GPS stand for “Global Positioning System”, which means “global positioning system”. This satellite system was developed in America. It was developed by order of the US Department of Defense.

The first GPS satellite was launched into orbit in 1974, about 20 years after the idea of ​​satellite navigation appeared. Another 20 years later, the GPS system was adopted by the United States and was used to guide missiles to ground and air targets. But nowadays this system is effectively used in for peaceful purposes to determine the exact coordinates of various objects.

But, nevertheless, the conditions for receiving GPS signals cannot guarantee 100% accuracy, because directly depend on the policy of the United States Department of Defense. GPS satellites move along 6 planes in orbit, each of which has 4 satellites. The satellites themselves have been launched and are functioning in abundance today. GPS uses CDMA code, which allows the receiver to be reduced to the size of a wristwatch.

Brief conclusions:

1. The main difference between GPS and GLONASS is “nationality”. GPS is an American satellite system, and GLONASS is Russian.
2. Differences in trajectories along planes. Eight GLONASS satellites move in three orbital planes; in GPS, satellites move in six different planes. GLONASS satellites are not yet enough for maximum efficiency, but GPS is a complete set.

What is GLONASS?

What is GPS?

Let's carry out short review these two systems.

GLONASS and GPS- These are global satellite positioning systems that allow you to determine the exact coordinates in three dimensions of any object on the surface (or near the surface) of the Earth. At the moment these are the two main and working systems in the world. What are their differences and what do they have in common?

What is GPS?

IN English language abbreviation GPS stands for "Global Positioning System" and translates as “global positioning system” - an American satellite navigation system developed by order of the US Department of Defense.

What is GLONASS?

Abbreviation GLONASS stands for "Global Navigation Satellite System"- first Soviet and then Russian satellite navigation system, developed by order of the USSR Ministry of Defense.

When did the idea of ​​satellite navigation come about?

Satellite navigation as an idea originated back in the days when the USSR launched the first artificial satellite Earth, i.e. in one thousand nine hundred and fifties. By observing and studying the signals emanating from this satellite, scientists discovered that using them in a special way and knowing the coordinates of the satellite, they can determine their coordinates with great accuracy. After this discovery, the military departments of the USA and the USSR began to develop developments in the field of creating a global navigation satellite system.

GPS system

The first test satellite of the GPS system was launched into orbit by the United States only 20 years after the idea of ​​satellite navigation appeared, in 1974. Another 20 years later, the GPS system was completed with the required number of satellites (24 pieces) and was put into service in this form. After that it became possible use GPS systems for military purposes to accurately guide missiles to ground and air targets.

GLONASS system

The Soviet Union launched its first GLONASS satellite into orbit only in 1982, but already in December 1995 the GLONASS system was brought to its full standard number of 24 satellites.

Officially, both navigation systems (GPS in the USA, GLONASS in the Russian Federation) were put into operation in 1993!

Unfortunately, later funding for the GLONASS system ceased and in 2001 only six satellites remained in orbit in working order. In 2001, Russia adopted the federal target program “Global navigation system" According to this program, by the end of 2009, the GLONASS system was to be fully equipped with 24 satellites and operate in full standard condition.

What do GPS and GLONASS systems have in common?

Despite the fact that navigation systems were originally developed for military purposes, nowadays GPS and GLONASS are actively used for peaceful purposes. Application area satellite systems is constantly expanding, and technology is rapidly developing. Already everywhere, in regular stores, navigators for cars, for people, for animals are sold; GPS signal receivers are built into mobile phones and PDAs. Anyone can see their location on the map, the speed of movement, easily and quickly plot routes and find the necessary addresses on the map, or, by installing receivers of satellite navigation systems on other moving objects, monitor all the movements of these objects.

Principle of coordinate measurement Russian system GLONASS is similar to the American GPS system.

What is the difference between GLONASS and GPS?

The main difference between the two satellite navigation systems is their nationality. Moreover, the conditions for receiving GPS signals are not 100% guaranteed and depend entirely on the policy of the US Department of Defense.

In a technical sense, the main difference between GLONASS and GPS is that GLONASS satellites in their orbital movement are not synchronized with the rotation of the Earth. This provides them with greater stability and does not require adjustments throughout the life of each satellite. However, GLONASS satellites have much more short term services.

For a long time, the global geopositioning system GPS, created in the United States, was the only one available to ordinary users. But even taking into account the fact that the accuracy of civilian devices was initially lower compared to military analogues, it was sufficient for both navigation and tracking the coordinates of cars.

However, back in the Soviet Union it was developed own system coordinate determination, known today as GLONASS. Despite the similar principle of operation (calculation of time intervals between signals from satellites is used), GLONASS has serious practical differences from GPS, due to both development conditions and practical implementation.

• GLONASS is more accurate in northern regions. This is explained by the fact that significant military groups of the USSR, and subsequently Russia, were located precisely in the north of the country. Therefore, the mechanics of GLONASS were calculated taking into account accuracy in such conditions.
• For uninterrupted operation of the GLONASS system no correction stations required. To provide GPS accuracy, whose satellites are stationary relative to the Earth, a chain of geostationary stations is needed to monitor inevitable deviations. In turn, GLONASS satellites are mobile relative to the Earth, so the problem of correcting coordinates is absent initially.

For civilian use, this difference is noticeable. For example, in Sweden 10 years ago it was GLONASS that was actively used, despite a large number of pre-existing GPS equipment. A considerable part of the territory of this country lies at the latitudes of the Russian North, and the advantages of GLONASS in such conditions are obvious: the lower the satellite’s inclination to the horizon, the more accurately the coordinates and speed of movement can be calculated with equal accuracy in estimating the time intervals between their signals (set by the navigator equipment).

So which is better?

It is enough to evaluate modern market telematics systems to get the correct answer to this question. Using in navigation or security system connection to GPS satellites and GLONASS simultaneously, three main advantages can be achieved.

• High accuracy. The system, analyzing current data, can select the most correct of the available ones. For example, at the latitude of Moscow, GPS now provides maximum accuracy, while in Murmansk GLONASS will become the leader in this parameter.
• Maximum reliability. Both systems operate on different channels, therefore, when faced with deliberate jamming or interference from outsiders in the GPS range (as in the more common one), the system will retain the ability to geoposition via the GLONASS network.
• Independence. Since both GPS and GLONASS are originally military systems, the user may face deprivation of access to one of the networks. To do this, the developer only needs to introduce software restrictions into the implementation of the communication protocol. For the Russian consumer, GLONASS is becoming, to some extent, in a backup way work in case of GPS unavailability.

That is why the Caesar Satellite systems offered by us, in all modifications, use dual geopositioning, supplemented by coordinate tracking by base stations cellular communications.

How truly reliable geolocation works

Consider the work reliable system GPS/GLONASS tracking using the example of Cesar Tracker A.

The system is in sleep mode, not transmitting data to cellular network and turning off GPS and GLONASS receivers. This is necessary to save the maximum possible resource of the built-in battery and, accordingly, ensure greatest autonomy system that protects your car. In most cases, the battery lasts for 2 years. If you need to locate your car, for example, if it is stolen, you need to contact the Caesar Satellite security center. Our employees are transferring the system to active state and receive data about the location of the car.

During the transition to active mode Three independent processes occur simultaneously:

• Triggered GPS receiver, analyzing the coordinates using your geopositioning program. If less than three satellites are detected within a given period of time, the system is considered unavailable. The coordinates are determined using the GLONASS channel in a similar way.
• The tracker compares data from both systems. If a sufficient number of satellites have been detected in each, the tracker selects the data that it considers more reliable and accurate. This is especially true in case of active electronic countermeasures - jamming or substitution of the GPS signal.
• The GSM module processes geopositioning data via LBS (cellular base stations). This method is considered the least accurate and is used only if both GPS and GLONASS are not available.

Thus, modern system tracking has triple reliability, using three geopositioning systems separately. But, naturally, it is the GPS/GLONASS support in the tracker design that ensures maximum accuracy.

Application in monitoring systems

Unlike beacons, monitoring systems used in commercial vehicles constantly monitor the location of the vehicle and its current speed. With this application, the advantages of dual GPS/GLONASS geopositioning are revealed even more fully. Duplication of systems allows:

• support monitoring in case of short-term problems with signal reception from GPS or GLONASS;
• maintain high accuracy regardless of flight direction. Using a system like CS Logistic GLONASS PRO, you can confidently carry out flights from Chukotka to Rostov-on-Don, saving full control over transport throughout the entire route;
• protect commercial vehicles from opening and theft. Caesar Satellite servers receive real-time information about the time and exact location of the car;
• effectively counteract hijackers. The system saves internal memory the maximum possible amount of data even if the communication channel with the server is completely unavailable. Information begins to be transmitted at the slightest interruption of radio jamming.

By choosing a GPS/GLONASS system, you provide yourself with the best service and security capabilities in comparison with systems that use only one of the geopositioning methods.