What are the Glonass models? Gps vs Glonass: which system is better. Brief description of the concept of a unified differential system

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, the Soviet Union developed its own coordinate determination system, 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 conditions 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 systemno 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, GLONASS was actively used, despite the large amount of already 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 the modern telematics systems market to get the correct answer to this question. By using a connection to GPS and GLONASS satellites simultaneously in a navigation or security system, 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 tracking coordinates by base stations cellular communication.

How truly reliable geolocation works

Let's look at the operation of a reliable GPS/GLONASS tracking system using the Cesar Tracker A as an example.

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, respectively, to ensure the greatest autonomy of the 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 switch the system to an 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 operate flights from Chukotka to Rostov-on-Don, maintaining 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.

The idea of ​​locating objects using artificial Earth satellites came to the minds of Americans back in the 1950s. However, the Soviet satellite pushed scientists.

American physicist Richard Kershner realized that if you know the coordinates on the ground, you can find out the speed of the Soviet spacecraft. This is where the deployment of the program began, which later became known as GPS - the global positioning system. In 1974, the first American satellite was launched into orbit. Initially this project was intended for the military departments.

How geolocation works

Let's look at the features of geopositioning using the example of a regular tracker. Until activation, the device is in standby mode, the GPS GLONASS module is turned off. This option is provided to save battery charge and increase the period battery life devices.

During activation, three processes are launched at once:

• The GPS receiver begins to analyze the coordinates using the built-in program. If three satellites are detected at this moment, the system is considered unavailable. The same thing happens with GLONASS;
• if a tracker (for example, a navigator) supports modules of two systems, then the device analyzes the information received from both satellites. Then it reads the information that it considers reliable;
• if at the right time the signals of both systems are not available, then GSM is turned on. But the data obtained in this way will be inaccurate.

Therefore, when wondering what to choose – GPS or GLONASS, choose equipment that supports two satellite systems. The disadvantages of one of them will be covered by the other. Thus, signals from 18-20 satellites are available to the receiver simultaneously. This ensures good signal level and stability and minimizes errors.

Cost of GPS and GLONASS monitoring service

Several factors influence the final cost of equipment:

• manufacturer country;
• what navigation systems are used;
• quality of materials and additional functions;
• software maintenance.

The most budget option is Chinese-made equipment. The price starts from 1000 rubles. However, you should not expect quality service. For that kind of money, the owner will receive limited functionality and a short service life.

The next equipment segment is European manufacturers. The amount starts from 5,000 rubles, but in return the buyer receives stable software and advanced functions.

Russian manufacturers offer quite cost-effective equipment at reasonable prices. Prices for domestic trackers start at 2,500 rubles.

A separate expense item is the subscription fee and payment for additional services. Monthly fee for domestic companies – 400 rubles. European manufacturers open up additional options for an additional “coin”.

You will also have to pay for installation of equipment. On average, installation at a service center will cost 1,500 rubles.

Advantages and disadvantages of GLONASS and GPS

Now let's look at the pros and cons of each system.

GPS satellites hardly appear in the southern hemisphere, while GLONASS transmits signals to Moscow, Sweden and Norway. The signal clarity is higher in the American system thanks to 27 active satellites. The difference in error “plays into the hands” of US satellites. For comparison: the inaccuracy of GLONASS is 2.8 m, that of GPS is 1.8 m. However, this is an average figure. The purity of the calculations depends on the position of the satellites in orbit. In some cases, the devices are lined up in such a way that the degree of miscalculation increases. This situation occurs in both systems.

Summary

So which will win in the GPS vs GLONASS comparison? Strictly speaking, civilian users do not care what satellites their navigation equipment uses. Both systems are free and located in open access. A reasonable solution for developers would be mutual integration of systems. In this case, the tracker will have the required number of devices in its “field of view” even in adverse weather conditions and interference in the form of high-rise buildings.

GPS and GLONASS. Video on the topic

Paper maps of the area have been replaced by electronic maps, navigation on which is carried out using the GPS satellite system. From this article you will learn when satellite navigation appeared, what it is now and what awaits it in the near future.

During World War II, the US and British flotillas had a powerful trump card - the LORAN navigation system using radio beacons. At the end of hostilities, civilian ships of “pro-Western” countries received the technology at their disposal. A decade later, the USSR put into operation its answer - the Chaika navigation system, based on radio beacons, is still in use today.

But land navigation has significant drawbacks: uneven terrain becomes an obstacle, and the influence of the ionosphere negatively affects the signal transmission time. If the distance between the navigation radio beacon and the ship is too large, the error in determining the coordinates can be measured in kilometers, which is unacceptable.

Ground-based radio beacons were replaced by satellite navigation systems for military purposes, the first of which, the American Transit (another name for NAVSAT), was launched in 1964. Six low-orbit satellites ensured coordinate determination accuracy of up to two hundred meters.

In 1976, the USSR launched a similar military navigation system, Cyclone, and three years later, a civilian one called Cicada. The big disadvantage of early satellite navigation systems was that they could only be used a short time for an hour. Low-orbit satellites, and even in small numbers, were not able to provide wide signal coverage.

GPS vs. GLONASS

In 1974, the US Army launched into orbit the first satellite of the then new NAVSTAR navigation system, which was later renamed GPS (Global Positioning System). In the mid-1980s, GPS technology was allowed to be used by civilian ships and aircraft, but for a long time they were able to provide much less accurate positioning than military ones. The twenty-fourth GPS satellite, the last required to completely cover the Earth's surface, was launched in 1993.

In 1982, the USSR presented its answer - it was GLONASS (Global Navigation Satellite System) technology. The final 24th GLONASS satellite entered orbit in 1995, but the short service life of the satellites (three to five years) and insufficient funding for the project put the system out of action for almost a decade. It was possible to restore worldwide GLONASS coverage only in 2010.

To avoid such failures, both GPS and GLONASS now use 31 satellites: 24 main and 7 reserve, as they say, just in case. Modern navigation satellites fly at an altitude of about 20 thousand km and manage to circle the Earth twice in a day.

How GPS works

Positioning in the GPS network is carried out by measuring the distance from the receiver to several satellites, the location of which is precisely known at the current moment in time. The distance to the satellite is measured by multiplying the signal delay by the speed of light.
Communication with the first satellite provides information only about the range of possible locations of the receiver. The intersection of two spheres will give a circle, three - two points, and four - the only correct point on the map. Our planet is most often used as one of the spheres, which allows positioning on only three instead of four satellites. In theory, GPS positioning accuracy can reach 2 meters (in practice, the error is much larger).

Each satellite sends a large set of information to the receiver: exact time and its correction, almanac, ephemeris data and ionospheric parameters. An accurate time signal is required to measure the delay between its sending and receiving.

Navigation satellites are equipped with high-precision cesium clocks, while receivers are equipped with much less accurate quartz clocks. Therefore, to check the time, contact is made with an additional (fourth) satellite.

But cesium clocks can also make mistakes, so they are checked against hydrogen clocks placed on the ground. For each satellite, the time correction is individually calculated in the navigation system control center, which is subsequently sent to the receiver along with the exact time.

Another important component of the satellite navigation system is the almanac, which is a table of satellite orbit parameters for the month ahead. The almanac, as well as the time correction, are calculated in the control center.

Satellites also transmit individual ephemeris data, on the basis of which orbital deviations are calculated. And given that the speed of light is not constant anywhere except in vacuum, the signal delay in the ionosphere must be taken into account.

Data transmission in the GPS network is carried out strictly at two frequencies: 1575.42 MHz and 1224.60 MHz. Different satellites broadcast on the same frequency, but use CDMA code division. That is, the satellite signal is just noise, which can only be decoded if you have the appropriate PRN code.

The above approach allows for high noise immunity and the use of a narrow frequency range. However, sometimes GPS receivers still have to search for satellites for a long time, which is caused by a number of reasons.

Firstly, the receiver initially does not know where the satellite is, whether it is moving away or approaching, and what the frequency offset of its signal is. Secondly, contact with a satellite is considered successful only when a complete set of information is received from it. The data transmission speed in the GPS network rarely exceeds 50 bps. And as soon as the signal is interrupted due to radio interference, the search begins again.

The future of satellite navigation

Now GPS and GLONASS are widely used for peaceful purposes and, in fact, are interchangeable. The latest navigation chips support both communication standards and connect to those satellites that are found first.

The American GPS and Russian GLONASS are far from the only satellite navigation systems in the world. For example, China, India and Japan have begun to deploy their own satellite systems called BeiDou, IRNSS and QZSS, respectively, which will operate only within their countries and therefore require a relatively small number of satellites.

But perhaps the greatest interest is in the Galileo project, which is being developed by the European Union and should be launched at full capacity before 2020. Initially, Galileo was conceived as a purely European network, but countries in the Middle East and South America have already expressed their desire to participate in its creation. So, a “third force” may soon appear in the global CLO market. If this system is compatible with existing ones, and most likely it will be, consumers will only benefit - the speed of searching for satellites and positioning accuracy should increase.

Today it is difficult to find an area of ​​socio-economic development in which satellite navigation services could not be used. The most relevant application of GLONASS technologies remains in the transport industry, including sea and river navigation, air and land transport. At the same time, according to experts, about 80% of navigation equipment is used in road transport.

GROUND TRANSPORT

One of the main areas of application of satellite navigation is transport monitoring. This service is most important for industrial, construction, and transport enterprises. Navigation equipment that receives signals from the GLONASS system allows you to determine the location of the vehicle, indications measuring sensors can ensure both the safety of passenger transportation and the convenience and optimization of the operation of commercial vehicles, and eliminate its inappropriate use. The implementation of the system allows fleet owners to reduce their maintenance costs by 20-30% in 4-6 months.

One of the technologies implemented in Russia based on satellite navigation is the Intelligent Transport System (ITS). It includes monitoring the transportation of dangerous, large and heavy cargo, monitoring the work and rest schedule of drivers, managing and dispatching passenger transportation, and informing urban transport passengers.

The effectiveness of using satellite navigation services in ground transport can be assessed according to the following criteria:

• reduction in the number of road accidents, as well as deaths and injuries in road accidents, reduction in response time to road accidents;
• reducing travel time, increasing the attractiveness of public transport;
• improving the quality of spending budget funds.

According to experts, due to the introduction of intelligent transport systems, Russia’s GDP growth could reach 4-5% per year.

Municipal and public transport of the Altai, Krasnodar, Krasnoyarsk, Stavropol, Khabarovsk territories, Astrakhan, Belgorod, Vologda, Kaluga, Kurgan, Magadan, Moscow, Nizhny Novgorod, Novosibirsk, Penza, Rostov, Samara are equipped with monitoring and navigation and information technologies based on the services of the GLONASS system , Saratov, Tambov, Tyumen regions, Moscow, the republics of Mordovia, Tatarstan, Chuvashia. In Russia as a whole, ITS elements have been implemented and are operating effectively in more than 100 cities.

SEARCH AND RESCUE

Equipment that receives signals from navigation satellites is installed on ambulances, as well as vehicles Ministry of Emergency Situations services. Coordinate-time support based on satellite data allows teams of doctors and rescuers to arrive more quickly at emergency sites to provide assistance to victims. Using GLONASS, the location and movement of groups of firefighters is tracked.

One of the illustrative examples of the use of global satellite navigation in the interests of saving human lives is the ERA-GLONASS system (emergency response in case of accidents). Its main task is to determine the fact of a traffic accident and transmit data to the response server. If a car crashes, the navigation and telecommunications terminal installed on it automatically determines the coordinates, establishes a connection with the server center of the monitoring system and transmits data about the accident via cellular communication channels to the operator. These data make it possible to determine the nature and severity of an accident and carry out an immediate response by ambulances. The use of Global Navigation Satellite System data via ERA-GLONASS can significantly reduce the mortality rate from injuries resulting from road accidents.

Another area of ​​application of GLONASS in the interests of saving human lives is the combination of global satellite navigation with the COSPAS-SARSAT International Search and Rescue System. This function is provided on the latest generation Glonass-K navigation spacecraft. Already at the stage of flight testing, the Glonass-K satellite No. 11 in March 2012, through a repeater of this system, transmitted a distress signal about a crashed Canadian helicopter, thanks to which the crew was saved.

PERSONAL NAVIGATION

Chipsets with GLONASS navigation receivers are used in smartphones, tablets, digital cameras, fitness devices, wearable trackers, laptops, navigators, watches, glasses and other devices. Personal navigation is becoming the main application area for satellite navigation technologies.

The use of GNSS technologies has contributed to the emergence of completely new sports and outdoor activities. An example of this is geocaching - a tourist game using satellite navigation systems, the point of which is to find caches hidden by other participants in the game. Another new sport of geotagging is cross-country racing using predetermined satellite coordinates.

A promising area of ​​application of GLONASS technologies is social systems providing assistance to people with disabilities or young children. Using navigation equipment with a voice interface, a blind person can determine his way to a store, clinic, etc. Owners of such devices can, in the event of danger or a sharp deterioration in health, cause emergency assistance by pressing the panic button. A personal satellite tracker can help parents track their child's location online to monitor their safety.

AVIATION

In aviation, navigation receivers are integrated into on-board air navigation systems that provide route navigation and landing approaches in difficult weather conditions. Satellite navigation is of great importance for ensuring the landing of small aircraft at unequipped airfields. GLONASS-based navigation systems increase the safety of helicopter navigation and increase the accuracy of navigation of unmanned aerial vehicles.

WATER TRANSPORT

The use of GNSS technologies for marine/river purposes in Russia is approaching 100%. The capacity of the Russian market is estimated at 18,560 units of water transport, including cargo and passenger river and sea vessels. GLONASS technologies are used in shipping when guiding vessels and maneuvering difficult conditions(locks, ports, canals, straits, ice conditions), navigation on inland waterways, monitoring and accounting of the fleet, rescue operations.

The growth in traffic along the Northern Sea Route, which can significantly reduce the delivery time of goods from the Asia-Pacific region to Europe, leads to an increase in the intensity of shipping in an area with extremely harsh climatic conditions. In conditions of storms and dense fog, it is difficult to ensure the safety of ship traffic without satellite navigation.

GEODESY AND CARTOGRAPHY

GLONASS technologies are used in city and land cadastre, planning and management of territorial development, and for updating topographic maps. The use of GLONASS technologies speeds up and reduces the cost of creating maps and updating them - in some cases, there is no need for expensive aerial photography or labor-intensive topographic surveys. IN Russian Federation The current market volume of geodetic equipment based on GNSS is estimated at 2.3 thousand units.

ENVIRONMENT

The scientific community actively uses navigation data for Earth observations and research. GLONASS promotes the development of methods and tools designed to solve fundamental problems of geodynamics, the formation of the Earth's coordinate system, building a model of the Earth, measuring tides, currents and sea level, determining and synchronizing time, localizing oil spills, and reclaiming land after hazardous waste disposal.

Navigation signals from GLONASS spacecraft play an important role in the study of seismic processes. Using satellite data, it is possible to record the processes of displacement of tectonic plates more accurately than through ground-based equipment. In addition, disturbances in the ionosphere, recorded using navigation satellites, provide scientists with data about approaching movements of the earth's crust. Thus, global satellite navigation makes it possible to predict earthquakes and minimize their consequences for humans. Technologies based on GLONASS also help to monitor automobile and railways in avalanche-prone areas in mountainous areas.

SPACE NAVIGATION

In the space industry, GLONASS technologies are used to track launch vehicles, highly accurately determine the orbits of spacecraft, determine the orientation of a spacecraft relative to the Sun, and for precise observation, control and target designation of missile defense systems.

In particular, the following equipment is equipped with GLONASS or GLONASS/GPS satellite navigation equipment: the Proton-M launch vehicle, the Soyuz launch vehicle, the Breeze, Fregat, DM upper stages, and the Meteor-M spacecraft. , “Ionosphere”, “Canopus-ST”, “Condor-E”, “Bars-M”, “Lomonosov”, as well as railway mobile complexes used for transporting launch vehicles and rocket fuel components.

In the space industry, a large number of projects require high-precision knowledge of spacecraft orbits when solving problems of remote sensing of the Earth, reconnaissance, mapping, monitoring of ice conditions, emergency situations, as well as in the field of studying the Earth and the world ocean, building a high-precision dynamic model of the geoid, high-precision dynamic models of the ionosphere and atmosphere. At the same time, the accuracy of knowledge of the position of objects is required at the level of several centimeters; special methods for processing measurements of the GLONASS system from receivers located on board the spacecraft can successfully solve this problem.

CONSTRUCTION

In Russia, GLONASS technologies are used in monitoring construction equipment, as well as monitoring the displacement of the roadway, monitoring deformations of linear stationary objects, and in control systems for road construction equipment.

Satellite navigation services help in determining the location of geographical objects with centimeter accuracy when laying oil and gas pipelines, power lines, and clarifying terrain parameters during the construction of buildings and structures, and road construction. According to domestic and foreign experts, the use of GLONASS increases the efficiency of construction and cadastral work by 30-40%.

The use of GLONASS services allows you to quickly transmit information about the condition of complex engineering structures and potentially dangerous objects, such as dams, bridges, tunnels, industrial enterprises, and nuclear power plants. With the help of satellite monitoring, specialists receive timely information about the need for additional diagnostics of these structures and their repair.

COMMUNICATION SYSTEMS

GLONASS is used for temporary logging of monetary transactions in stock, currency and commodity dealing. A continuous and accurate way of recording transfers and the ability to trace them is the basis of the operation of international trading systems for interbank trading. The largest investment banks use GLONASS to synchronize computer networks its branches throughout Russia. The united MICEX-RTS exchange uses GLONASS time signals to accurately record quotes when making transactions. GLONASS equipment, used in the interests of telecommunications infrastructure, provides solutions to the problems of synchronization of communication networks.

WEAPONS

The GLONASS system is of particular importance for the efficiency of problem solving by the Armed Forces and special users. The system is used to solve problems of coordinate-time support for all types and branches of troops, including to increase the efficiency of the use of high-precision weapons, unmanned aircraft, and operational command and control of troops.

Satellite positioning and navigation systems, originally developed for military needs, have recently found wide application in the civilian sphere. GPS/GLONASS monitoring of transport, monitoring people in need of care, monitoring the movements of employees, tracking animals, tracking luggage, geodesy and cartography are the main areas of use of satellite technologies.

Currently, there are two global satellite positioning systems created in the USA and the Russian Federation, and two regional ones, covering China, the countries of the European Union and a number of other countries in Europe and Asia. GLONASS monitoring and GPS monitoring are available in Russia.

GPS and GLONASS systems

GPS (Global Position System) is a satellite system whose development began in America in 1977. By 1993, the program was deployed, and by July 1995, the system was fully ready. Currently, the GPS space network consists of 32 satellites: 24 main, 6 backup. They orbit the Earth in a medium-high orbit (20,180 km) in six planes, with four main satellites in each.

On the ground there is a main control station and ten tracking stations, three of which transmit correction data to the latest generation satellites, which distribute them to the entire network.

The development of the GLONASS (Global Navigation Satellite System) system began in the USSR in 1982. The completion of the work was announced in December 2015. GLONASS requires 24 satellites to operate, 18 are sufficient to cover the territory and the Russian Federation, and the total number of satellites located in this moment in orbit (including reserve ones) - 27. They also move in a medium-high orbit, but at a lower altitude (19,140 km), in three planes, with eight main satellites in each.

GLONASS ground stations are located in Russia (14), Antarctica and Brazil (one each), and a number of additional stations are planned to be deployed.

The predecessor to GPS was the Transit system, developed in 1964 to control the launch of missiles from submarines. It could locate exclusively stationary objects with an accuracy of 50 m, and the only satellite was in view for only one hour a day. GPS program previously bore the names DNSS and NAVSTAR. In the USSR, the creation of a navigation satellite system began in 1967 as part of the Cyclone program.

The main differences between GLONASS and GPS monitoring systems:

• American satellites move synchronously with the Earth, while Russian satellites move asynchronously;
• different heights and number of orbits;
• their different angles of inclination (about 55° for GPS, 64.8° for GLONASS);
• different signal formats and operating frequencies.

Benefits of GPS

• GPS is the oldest existing positioning system; it was fully operational before the Russian one.
• Reliability comes from using a larger number of redundant satellites.
• Positioning occurs with a smaller error than GLONASS (on average 4 m, and for the latest generation satellites - 60–90 cm).
• Many devices support the system.

Advantages of the GLONASS system

• The position of asynchronous satellites in orbit is more stable, which makes them easier to control. Regular adjustments are not required. This advantage important for specialists, not consumers.
• The system was created in Russia, therefore it ensures reliable signal reception and positioning accuracy in northern latitudes. This is achieved due to the greater angle of inclination of satellite orbits.
• GLONASS is a domestic system and will remain available to Russians if GPS is turned off.

Disadvantages of the GPS system

• Satellites rotate synchronously with the rotation of the Earth, so accurate positioning requires the operation of corrective stations.
• A low tilt angle does not provide a good signal and accurate positioning in polar regions and high latitudes.
• The right to control the system belongs to the military, and they can distort the signal or completely disable GPS for civilians or for other countries in the event of a conflict with them. Therefore, although GPS for transport is more accurate and convenient, GLONASS is more reliable.

Disadvantages of the GLONASS system

• The development of the system began later and until recently was carried out with a significant lag behind the Americans (crisis, financial abuse, theft).
• Incomplete set of satellites. The service life of Russian satellites is shorter than that of American satellites, they require repair more often, so the accuracy of navigation in a number of areas is reduced.
• GLONASS satellite vehicle monitoring is more expensive than GPS due to the high cost of devices adapted to work with the domestic positioning system.
• Flaw software for smartphones, PDAs. GLONASS modules were designed for navigators. For compact portable devices Today it is more common and affordable option– is it support for GPS-GLONASS or GPS only.

Summary

GPS and GLONASS systems are complementary. The optimal solution is satellite GPS-GLONASS monitoring. Devices with two systems, for example, GPS markers with the M-Plata GLONASS module, provide high positioning accuracy and reliable operation. If for positioning exclusively using GLONASS the error averages 6 m, and for GPS – 4 m, then when using two systems simultaneously it decreases to 1.5 m. But such devices with two microchips are more expensive.

GLONASS was developed specifically for Russian latitudes and is potentially capable of providing high accuracy; due to its understaffing with satellites, the real advantage is still on the side of GPS. The advantages of the American system are the availability and wide selection of GPS-enabled devices.