The Birth Background of Beidou Navigation and Positioning System
First of all, since the 1950s, the Soviet Union took the lead in sending the first artificial satellite "Putnik 1" into space, which opened the space age of mankind. However, by studying the orbit data of this Soviet satellite, two physicists in the Applied Physics Laboratory of Johns Hopkins University in the United States put forward a preliminary idea of satellite positioning system, which opened the door to the era of satellite navigation.
1964, the United States took the lead in building the world's first satellite navigation system-"meridian satellite system" consisting of six satellites. 1980, the United States took the lead in building the world's first global satellite navigation system-GPS system consisting of 24 satellites. As a product of the Cold War between the United States and the Soviet Union, GPS really showed its power in the Gulf War of 1990, when the disintegration of the Soviet Union was a foregone conclusion, and China was shocked by its power.
The performance of precision guided weapons equipped with GPS system in the war left a deep impression on our army and began to realize the military value of satellite navigation system.
1993' s "Galaxy Incident" undoubtedly stimulated our country again and showed the importance of satellite navigation system to our country again.
In the second year of the "Yinhe Incident", the China government approved the "Double Star Positioning System" scheme of Chen Fangyun, an academician of the Chinese Academy of Sciences and winner of the "Two Bombs and One Satellite Meritorious Medal", and officially started the construction of Beidou satellite navigation system. The so-called "double star positioning system" was put forward by Chen Fangyun and his collaborators in 1983. Based on the principle of three-ball positioning, two synchronous satellites are used for simultaneous positioning and communication. During the period of 1989, Chen Fangyun team carried out a double-star positioning experiment through communication satellites, which verified the feasibility of the double-star positioning technology.
The time span from 1989 verified by double-star positioning technology to 1994 started by Beidou satellite navigation system is as long as five or six years. I'm afraid the biggest reason is not technical problems, but financial problems. China was too poor at that time. It is conceivable that without the stimulation of the Gulf War and the "Yinhe Incident", the start-up of Beidou satellite navigation system would be delayed again and again.
The "three-step" strategy of "regional first, global later" is in line with the national conditions.
In the construction of Beidou satellite navigation system, China follows the principle of gradual construction, and will gradually implement it according to the three-step master plan, from serving China to the Asia-Pacific region, and finally to serving the whole world. What are the three steps of Beidou's three-step strategy?
In the first step, 1994 started the construction of Beidou satellite navigation test system, and in 2000, the regional active service capacity was formed. Using a small number of geostationary orbit satellites to complete the test task has accumulated technical experience for the construction of Beidou satellite navigation system, trained specialized personnel and developed some ground application infrastructure equipment.
The second step is to start the construction of Beidou satellite navigation system in 2004, and by 20 12, the Beidou satellite navigation system covering the Asia-Pacific region will be completed, with the ability of positioning, navigation, timing and short message communication services covering the Asia-Pacific region.
Third, a global satellite navigation system consisting of five geostationary orbit satellites and 30 non-geostationary orbit satellites will be built this year, with global passive service capability.
Comparison of Beidou navigation system with GPS, GLONASS and Galileo
Origin and characteristics of GPS/BDS /GLONASS/ Galileo
BDS: The global satellite navigation system independently developed by China consists of three parts: space segment, ground segment and user segment. It can provide high-precision and high-reliability positioning, navigation and timing services for all kinds of users around the world, and has the ability of short message communication. It has initially possessed the ability of regional navigation, positioning and time service, with positioning accuracy of10m and time service accuracy of 0.2m per second.
GPS: An omni-directional, all-weather, all-day and high-precision satellite navigation system developed by the U.S. Department of Defense, which can provide low-cost and high-precision three-dimensional navigation information such as position, speed and accurate timing for users all over the world. GPS can provide vehicle positioning, anti-theft, anti-robbery, driving route monitoring and call command. To achieve all the above functions, we must have three elements: GPS terminal, transmission network and monitoring platform.
GLONASS: The system was first developed during the Soviet period, and then Russia continued this plan. From 65438 to 0993, Russia began to establish its own global satellite navigation system, which began to operate in 2007. At that time, only Russian satellite positioning and navigation services were opened. By 2009, its service scope has been extended to the whole world. The main services of the system include determining the coordinates and moving speed information of land, sea and air targets.
Galileo: A global satellite navigation and positioning system developed and established by the European Union. The plan was announced by Council of Europe in February 1999. The system consists of 30 satellites with an orbital height of 236 16km, including 27 working satellites and 3 backup satellites. The orbit height of the satellite is about 24,000 kilometers, which lies in three orbital planes with an inclination of 56 degrees.
Advantages of Beidou navigation system
1. High safety performance.
Before Beidou navigation, we used the American GPS satellite navigation system. Using GPS not only pays a high service fee to the United States every year, but also has a low safety factor for positioning and navigation. A few years ago, the media disclosed that the US military used GPS to monitor the troops of various countries to obtain information, and China would not be subject to people after using its own Beidou satellite system, and its safety factor would be greatly improved.
2. Accurate positioning accuracy
China Beidou satellite navigation consists of 35 satellites, including 5 geostationary satellites, 27 medium-earth satellites and 3 tilt synchronous satellites. With the increase of the number of satellites, the positioning accuracy and service range will be improved. Beidou satellite navigation system is independently developed and operated in China, so it will be given priority in China.
3. Tri-frequency signal
China's Beidou navigation system adopts the latest three-frequency signal scheme, and the United States' GPS adopts dual-frequency signals. Tri-frequency signal can better eliminate the influence of high-order ionospheric delay, enhance the data preprocessing ability, improve the efficiency of ambiguity determination, and thus improve the positioning reliability.
4. Active positioning and passive positioning
Active positioning requires the user's receiver to transmit signals to communicate with satellites, while passive positioning does not. The second generation of Beidou positioning adopts passive positioning. When the number of satellites above the user is small, it can still be located. At present, Beidou satellite navigation system has been equipped with short message communication service, which is a technical breakthrough of global positioning system. GPS in the United States can only communicate in one direction, while Beidou in China has realized the function of two-way communication, which is quite practical in dealing with major events!
Traffic application
With the increasing number of operating vehicles in China, all kinds of traffic accidents occur from time to time, causing great losses to people's lives and property. There are many reasons, among which the illegal behavior of the driver of the operating vehicle (such as speeding, changing lanes at will, occupying overtaking lanes for a long time, occupying emergency lanes, parking at will, etc.). ) is an important factor leading to highway accidents. Using the high-precision positioning lane-level navigation system of Beidou satellite navigation system, we can strengthen the control of driving behavior of operating vehicles, solve traffic law enforcement problems and improve management efficiency.
Application of GIS in Geological Surveying and Mapping
Using Beidou navigation and positioning technology to develop a general field survey information system of natural resources has the advantages of being compatible with all kinds of field surveying and mapping and realizing sub-meter positioning of field information collection.
The landslide real-time monitoring system based on Beidou-1 satellite navigation system developed by China Institute of Geological Environment Monitoring and Tsinghua University has achieved good application results in Ya 'an landslide area in Sichuan.
The Institute of Geomechanics of the Chinese Academy of Geological Sciences cooperated with Tsinghua University to develop a real-time monitoring system for in-situ stress in the Qinghai-Tibet Plateau based on Beidou-1 satellite navigation system.
Application in earthquake relief and emergency command
In the earthquake relief work after the "5. 12" Wenchuan earthquake, Beidou satellite navigation system played an important role, which ensured the smooth progress of earthquake relief and emergency command, and fully reflected the irreplaceable application of Beidou navigation and positioning system in earthquake relief. The application of Beidou satellite navigation system in "5. 12" earthquake relief mainly includes: ① providing navigation and positioning for "5. 12" earthquake relief helicopter; (2) In the case of communication interruption and road damage caused by the earthquake, it provided reliable communication guarantee for earthquake relief, established real-time communication channels for the frontline and headquarters of the disaster area, and timely transmitted the real-time situation of the disaster area back to the headquarters, which played a key role in the process of decision-making, search and rescue, medical treatment and so on. , laid a decisive foundation for the great victory of 5. 12 earthquake relief; (3) Providing remote monitoring and disaster early warning for disaster reduction and prevention; (4) Providing public emergency information service.
Application in flood control and emergency rescue
Beidou receiver is used to collect flood control and emergency rescue data, including accurate latitude and longitude positioning and current time (timing); Then the related data is transmitted to the flood control command center through the satellite communication terminal; The flood control command center uses these data to locate in the geographic information system (GIS), and then obtains real-time flood information, so as to carry out emergency rescue quickly and effectively and minimize losses.
abstract
As one of the four major satellite navigation systems in the world, Beidou satellite positioning and navigation system has developed well in the Pearl River Delta, Bohai Rim, Central China and Yangtze River Delta, and has been successfully applied in surveying and mapping, water conservancy, petroleum, fishery, mining, agriculture, marine transportation, industrial control, forest fire prevention, railway transportation, autonomous navigation application, public security and other fields.
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References:
[1] Fu Yifei. Past life of China Beidou [J]. Friends of Science, 20 19, (7): 6- 10. DOI: 10.3969
Chen Qian, Li Jiong. Analysis of the four major satellite navigation systems in the world [J]. Journal of Navigation and Positioning, 2020,8 (3):115-120.
Guo Jing, Wang, Qi Junfeng. Lane navigation system based on Beidou high-precision positioning [J]. Bulletin of Surveying and Mapping, 2020, (1):26-29.
Lu Daxin. Application of Beidou satellite navigation and positioning system in artificial island safety monitoring [J]. Enterprise Technology and Development, 2020, (5):13-14.
Hu Tian, Tang Zhiqing. Research and Implementation of General Field Investigation Information System of Natural Resources Based on Beidou Navigation and Positioning Technology [J]. Surveying and Mapping and Spatial Geographic Information, 2020,43 (3):118-120, 123.
Wen Jing, Meng, et al. Application of Beidou satellite navigation system in geological survey [J]. Journal of Geomechanics, 20 12, 18 (3): 2 13-223. DOI: 10.3969
Zhang Jinsheng. Application of Beidou system in flood fighting and disaster relief [J]. Information and Communication, 20 16, (12): 277-278. DOI: 10.3969/j . ISSN . 1673-667。