beidou navigation system. Working principle of GNSS beidou. Completing the creation of Beidou

When buying a smartphone or studying its capabilities, you come across information that this device supports Beidou or BDS.

In this regard, many become interested in what system we are talking about, what it is, and what new functions and capabilities it offers.

What is Beidou?

Beidou is a new navigation system developed in China. It was named after the constellation Ursa Major, or rather its Chinese name. Beidou was launched in 2000. This system is a direct analogue and competitor of the GPS system developed in the USA and the Russian GLONASS system. It is also used for both the armed forces and ordinary civilian users.

Title and relevance

To draw conclusions about the relevance of Beidou for smartphone owners outside of China, you need to know about the technology's coverage area, as well as the number of satellites and ground base stations that provide navigation support.

Currently, Beidou operates in limited functionality mode, since stable satellite signal reception has only been achieved over China. Over the rest of the land the signal is less stable, which is explained by the insufficient number of orbital devices. Chinese developers promise complete coverage of the entire globe by 2020. At the beginning of 2017, a stable signal from six satellites was observed over the European part of Russia, as well as over eastern Europe, and one base station was successfully built and launched in Belgium.

Of course, China’s creation of its own navigation system gives this country a number of advantages both in foreign policy and in general civil spheres. This country plans to significantly increase the number of operating satellites, and in number they will significantly exceed the existing GLONASS and GPS satellites.

Beidou in smartphones

But let’s leave aside discussions about the military sphere and world domination, let’s talk about ordinary smartphone owners. It is obvious that Chinese citizens will have access to the most stable navigation system in the near future. Due to the large number of satellites, access to geodata must be open even in difficult conditions, such as in tunnels.

What steps are smartphone manufacturers taking in this direction? Most Chinese brands provide parallel operation of Beidou, GPS and GLONASS. Other companies divide gadgets based on the market to which they will be supplied.

The ability of a smartphone to use the Beidou system is welcome, but not required. Of course, it's nice to have an additional navigation system, but at the moment it's unlikely to be useful to users outside of China.

Beidou Satellite Navigation System- Chinese satellite navigation system, consisting of two separate groups of satellites. The first constellation Badow-1, officially named the Experimental Satellite Navigation System, was launched in 2000 in a limited test mode and consisted of only three satellites. The second group of Beidou-2, also known as COMPASS, is under construction and is expected to be completed by 2020.

The system was named Beidou in honor of the constellation Ursa Major, which has long been used in navigation to find the North Star. The original idea of ​​​​creating a Chinese navigation system was proposed back in the 1980s. Chen Fangyun.

The Chinese National Space Administration has determined the following order of development of the Beidou system:

• 2000–2003: Beidou Experimental System, consisting of three satellites.
• 2012: Navigation system to cover China and the rest of Asia.
• 2020: Global Navigation System.

In the early 2000s, China's Beidou-1 was at least a generation behind GPS and GLONASS. The experimental satellite system was slower, produced worse results and was tens of times more expensive. In 2004, with the beginning of the creation of Beidou-2, technology was modernized and the situation changed for the better. It is planned that the new Beidou global satellite navigation system will consist of 35 satellites, among which 5 will be located in geostationary orbit and the remaining 30 in medium orbits, completely covering the Earth. As with other satellite systems, two levels of positioning services will be available - open and closed (for military). The open version will be available worldwide for ordinary users and, according to the developers, positioning accuracy will be up to 10 meters and speed up to 0.2 meters per second.

The Chinese side has yet to resolve issues with the American, European and Russian sides regarding the frequency ranges that Beidou will use. In the meantime, the Chinese satellite system operates on B1 and E2 signal frequencies with a frequency of 1561.098 MHz.

Beidou-2 was launched into commercial operation on December 27, 2012, as a navigation system for the Asia-Pacific region. Of the 16 satellites put into orbit, 11 are in use, and the remaining 5 perform a reserve function. The number of satellites will increase until 2020, and when the system reaches full capacity, it will begin to be used throughout the Earth.

BEIDOU– Northern Dipper is the Chinese name for the constellation Ursa Major) Chinese national satellite navigation system.

The BEIDOU system will provide two types of global and two types of regional services. Global services are services with open and authorized access. Regional services are wide area differential correction service and short message service.

Beidou satellite constellation

The Beidou-3M/G/I satellites represent the orbital segment of the third stage of deployment of China's Beidou navigation system, using medium-Earth orbit and inclined geosynchronous orbit satellites.

Global availability of this system is planned by 2020, when all satellites will be launched. The program is managed by the China Satellite Navigation Control Center.

The concept of a system using two geostationary spacecraft (working name of the Twinsat system) was experimentally tested in 1989. The experiment was carried out on the basis of two DFH-2/2A communications spacecraft already in orbit. In 1993, Beidou was established as a program to provide China with independent access to regional and global navigation, no longer relying on foreign systems such as the American GPS and Russian Glonass system.

The first generation of experimental Beidou satellites, launched in 2000 (Beidou-1A and 1B) and 2003 (Beidou 1C), were based on the DFH-3 geostationary communications platform. In 2004, the Beidou regional navigation system began operating with an accuracy of up to 20 meters.

Another satellite, Beidou-1, was launched into geostationary orbit in 2007 to ensure that the gap between the experimental and operational Beidou systems was bridged.

Characteristics	Beidou spacecraft in geostationary and geosynchronous inclined orbit	KA Beidou in medium circular orbit
Main contractor		China Academy of Space Technology CAST
Satellite platform	DFH-3/3B	DFH-3B
Duration of active existence	~ 15 years	~ 12 years
Weight	828 kg	1615 kg
Signals	B2 (open access)	B1 (with open and authorized access) B2 (open access) B3 (with authorized access)
BSU	2 Rb (made in China)	2 Rb (European production)
Additional features	laser reflectors	laser reflectors cosmic particle recorders

During the upgrade from experimental to operational Beidou system, China plans to launch a total of 35 satellites - 5 in geostationary orbit, 27 in medium orbit and 3 in inclined geosynchronous orbits.

CAST has developed three different satellites:

1. Beidou-3M for medium orbit (27 satellites),
2. Beidou-3I in inclined geosynchronous orbits (3 satellites),
3. Beidou-3G Satellites - geostationary orbits (5 satellites).

Beidou will provide two types of services:

• a free service that is open to everyone with a compatible terminal;
• limited service for military and other applications.

Free service will provide 10 meter position accuracy, 0.2 m/s velocity measurement and 10 nanosecond timing accuracy.

The limited service will have a tracking accuracy of 10 centimeters and will include signaled data to provide system status information to users.

Beidou-2

In 2010 and 2011, five Beidou-2I satellites were launched on powerful Long March 3A rockets to insert satellites into inclined geosynchronous orbits (55°) covering China and surrounding areas. By the end of 2011, the Beidou-2 system entered service for operators in China and surrounding areas with an initial accuracy of 25 meters, which was expected to improve as more satellites were launched.

Geostationary Beidou-3G satellites are based on the DFH-3B satellite platform provided by the China Academy of Space Technology (CAST), using components from the flight-proven DFH-3 platform and expanding its capabilities with more advanced payloads and reducing the overall weight of the platform.

The DFH-3B platform has a hexagonal shape measuring 2.2 by 2.0 by 3.1 meters with a mass of 3800+ kilograms. The Beidou satellites have a planned mass of about 4,600 kilograms with two three-segment solar panels that generate 6,800 watts of electricity. The satellite uses advanced navigation systems, including star and earth sensors, and attitude actuators, providing excellent stabilization on all three axes.

The accuracy of the station in geostationary orbit is +/- 0.05 degrees.

Beidou RNSS operates like the European Galileo and the American GPS, also using similar frequency bands. Rubidium atomic clocks provide the precise timing solutions needed to calculate the time delay from the time a signal is sent to its arrival at the receiver, which in turn allows the distance to the satellite to be calculated. In order for the receiver to calculate an accurate position, three simultaneous distance measurements to three different satellites are required.

The Beidou-2 spacecraft currently in operation transmit B1 and B2 signals, enabling open, free services in the Asia-Pacific region. It is assumed that navigation radio signals will be emitted in three frequency bands B1, B2 and B3, located in the same areas of the L-band as signals from other GNSS.

After the launch of a new generation spacecraft in 2015, the management of the Beidou program announced a change in the structure of the B1 navigation signal:

1. shift of the center frequency from 1561.098 MHz to 1575.42 MHz (like civil GPS L1 and Galileo E1 signals) and
2. changing the QPSK modulation to MBOC (similar to the modulation of the future GPS L1C and Galileo E1 signal).

This is aimed at ensuring the complementarity of the Beidou system with GNSS GALILEO and GPS.

Beidou uses eight different signals in four bands ranging from 1100 to 1600 MHz:

• B1 (carrier frequency: 1561.098 MHz / bandwidth: 4.092 MHz / modulation: QPSK),
• B1-2 (1589.742 / 4.092 / QPSK),
• B2 (1207.140/24/QPSK),
• B3 (1268.520/24/QPSK),
• B1-BOC (1575.42 / 16.368 / MBOC),
• B2-BOC (1207.140 / 30.69 / BOC 10.5),
• B3-BOC (1268.520 / 35.805 / BOC 15, 2.5),
• L5 (1176.450 / 24 / QPSK).

Beidou Ground Control Complex

It is built according to a classic centralized scheme: a network of request-free measuring stations generates readings of primary measurements of navigation parameters of radio signals from navigation spacecraft and transmits them to the system control center, which generates information placed on board the spacecraft through special earth stations.

The Beidou network of request-free measuring stations is also located in China. The long-term development strategy of the system involves the creation of a global network of stations to improve the accuracy of the Beidou system's navigation services.

Beidou navigation services became available in the Asia-Pacific region starting in December 2012.

Beidou land terminals were used after the 2008 Sichuan earthquake and became standard equipment for Chinese border guards. To measure plane coordinates, at least two satellites are required (accuracy increases with the third and fourth), which are in contact with the user terminal and a central ground station.

The user terminal receives a signal from one satellite and transmits a signal that is received by both satellites, which relay it to a ground station where the user's 2D position is calculated through the time delay of the two signals, which can be processed into 3D information using a topographic map in an algorithm that gives the user's position, which is then transmitted back via an encrypted satellite link. 150 users can be served simultaneously with this type of position search.

In size, which could have serious consequences both for the industry and for US national security. At the same time, the first BeiDou satellite was launched only in 2000 - 22 years after the start of deployment of the US navigation system.

The Nikkei publication analyzed the data and revealed the rapid growth of BeiDou. In 2018 alone, China launched 18 satellites for its navigation system. As of the end of June 2019, 35 BeiDou satellites were in operation, while the GPS network consisted of only 31 devices, the European navigation system - 22 satellites, and the Russian GLONASS - 24. Japan has 4 local satellites, and India - 6. Chinese satellites were observed more frequently than GPS satellites in 130 of 195 countries. More than 20 BeiDou satellites have been detected over mainland China.

China is using its Belt and Road Initiative to promote its BeiDou navigation system. BeiDou satellites were prevalent in 100 of the 137 countries that joined the massive infrastructure project, most of them in Southeast Asia and Africa.

More than 30 countries in the Middle East, Africa and other countries use the Chinese navigation system. If it becomes the standard navigation system in these regions, China will have an advantage in introducing new technologies and products.

The report of the US-China Economic and Security Commission, presented by the US Congress, indicates that the Chinese authorities will invest up to $10.6 billion in their navigation system from 1994 to 2020. By 2020, China plans to launch about 10 more satellites, which will improve location accuracy and strengthen BeiDou's position.

2018: Completion of Beidou creation

The Chinese government plans to not only replace GPS in China with Beidou, but also offer basic satellite navigation services to its partners around the world, starting in late 2018.

According to Beidou chief designer Yang Changfeng, the launch of two more Beidou satellites into space was a key step in the transition of the national experimental system to a regional, and subsequently to an international navigation system. He also noted that the positioning accuracy of the satellites was increased from 5 to 2.5 meters in comparison with the previous generation BDS-2 satellites.

New navigation satellites were delivered into orbit using the Long March 3-B launch vehicle. The launch took place from the Xichang Cosmodrome (Sichuan Province, Southwestern China) at 02:07 local time (21:07 Moscow time). Three hours after launch, both satellites entered their designed medium-altitude near-Earth orbits.

By November 2018, there were 19 BDS-3 series satellites in orbit, and the Beidou system included 43 satellites in total. In 2019-2020, China plans to launch six more Beidou-3 series vehicles into medium-altitude low-Earth orbit.

2017: Russia and China will create a technology park for satellite navigation

In the fall of 2017, the State Commission for the Chinese Navigation Satellite System invited the State Corporation for Space Activities to participate in the creation of an international innovation center for the use of satellite navigation, central media reported.

It is expected that the joint center will develop applications based on satellite positioning

The structure can be created on the basis of one of the universities in China. All details of the project are planned to be discussed in May 2018 during the 9th China Satellite Navigation Conference in Harbin.

“The center will concentrate information on the latest achievements in the field, it will be possible to demonstrate equipment and apparatus, conduct training and improve knowledge. One might say, an analogue of Skolkovo, but with a specialization in satellite navigation,” the state corporation clarified.

Experts believe that the implementation of a joint Russian-Chinese project will contribute to strategic cooperation between the GLONASS and BeiDou systems, an agreement on which was reached at the political level.

Now the parties are working on the creation of a joint GLONASS/BeiDou receiver and are implementing a project on navigation and information support for cross-border crossings.

2012

At the end of 2012, the China Satellite Navigation Office published the signal specification for the Chinese Beidou navigation system. From now on, any manufacturer can produce receivers that use the signals of this system. There will most likely be those interested, despite the fact that there are still fewer working satellites in the Beidou system than, for example, in GLONASS.

According to plans, the Beidou system (translated from Chinese means “Northern Bucket”, which corresponds to the name of the constellation “Ursa Major”; sometimes the name “Compass” is also used) will consist of 35 satellites - five in geostationary orbits and thirty in medium-altitude orbits. The horizontal position accuracy of the Chinese satellite navigation system is expected to be 10 m, the time measurement accuracy is 10 nanoseconds, and the speed measurement accuracy is 0.2 m/s. Paying users will receive more accurate data, as well as the ability to communicate using satellite communications.

The idea to create its own navigation system appeared in China back in 1980. The first experimental satellite was launched in 2000. Beidou is currently scheduled to be fully deployed by 2020. In December 2012, Beidou began providing services to consumers in the Asia-Pacific region. There are currently 14 operational spacecraft in space. In 2012, six navigation satellites were launched.

The rapid progress in the construction of the Chinese navigation system looks like a miracle. Especially if you remember that back in 2009, the world was laughing at the story of the Beidou G2 spacecraft. Let me remind you: the Chinese navigation satellite G2 of the Beidou system was launched on April 15, 2009 and on April 23, as stated by the Chinese Xinhua agency, it entered its intended orbit. Soon after, it shifted 10 degrees from its orbit, became uncontrollable and began to drift westward, adding to the ranks of space debris. A similar story happened in 2007, when the Beidou 1D satellite, launched by China, got out of the control of Chinese specialists. Later, China attempted to raise Beidou 1D to 130 km to make it less dangerous for other countries' operating geostationary satellites.

Only three years have passed - and now Chinese navigation satellites are functioning properly and quite reliably, and noisy incidents no longer happen to them. According to measurements, the accuracy of determining coordinates in the Beidou system in the Asia-Pacific region is currently about 25 meters horizontally and 30 meters vertically. The Topographic Development Research Center of the State Bureau of Geodesy and Cartography of the People's Republic of China, together with the Public and Scientific Literature Publishing House, published a report some time ago on the development of satellite navigation in China in 2011. According to the document, this industry entered China during a period of rapid development. It is expected that by 2015 the industry's turnover will exceed 225 billion yuan (about $36 billion) and will become a new important point of growth for the national economy.

When choosing a new smartphone and studying the characteristics, you might have noticed such a parameter as BeiDou. This parameter began to appear in the characteristics of smartphones recently, so most users do not know what it means. In this article we will talk about what BeiDou is in a smartphone, how useful it is for Russian users and whether it is worth focusing on this parameter when choosing a new device.

BeiDou or Beidou is a Chinese satellite navigation system, an analogue of the American GPS system and the Russian GLONASS. China began construction of this navigation system back in 2000, when its first experimental version went into operation. In 2012, the system covered the territory of China and became available for commercial use.

BeiDou is planned to reach full capacity by 2020 and will include 5 satellites in geostationary orbit, 3 satellites in geosynchronous orbit, and 27 satellites in normal Earth orbit.

History of the creation of BeiDou

Despite the fact that the GPS navigation system is widely known to users, most ordinary people have not even heard of the BeiDou system, although it has existed for many years.

The development of BeiDou began back in 1983, when China decided to build its own navigation system. In 1989, the concept of a system based on two geostationary satellites was tested (the working name of the system was Twinsat).

In 1994, the first stage of construction of a full-fledged navigation system began. In 2000, China launched the first two satellites, which were placed in geostationary orbit. In 2003, the first phase of construction was completed, and the first generation BEIDOU navigation system was put into operation.

The second stage of construction of the BeiDou navigation system started in 2004 and by the end of 2012 the system already consisted of 14 satellites. Of which, 5 satellites operated in geostationary, 5 in inclined geosynchronous and 4 in conventional orbit. This constellation of satellites made it possible to provide navigation in the countries of the Asia-Pacific region.

The third phase of construction began in 2009. The main goal of this stage is to provide satellite navigation on the territory and waters of both Silk Roads (land and water), as well as to complete the deployment of a group of 35 satellites that will be able to provide global navigation by 2020.

BeiDou on a smartphone

Despite the fact that the BeiDou navigation system is still under construction, many smartphone manufacturers are already including its support in their devices. This is primarily done by Chinese manufacturers, but there are also manufacturers from other countries. For example, BeiDou support is available in many smartphones from Samsung, LG, ASUS and Sony.

In the future, when the BeiDou navigation system becomes global and works throughout the planet, it will certainly be supported in all smartphones produced. Data from the BeiDou system will complement the information received from GPS/GLONASS and smartphones will be able to determine their own location even more accurately.

But for now, there is no particular benefit from BeiDou for non-Chinese users. Therefore, when choosing a smartphone, you should not pay special attention to the support of this navigation system.