The composition characteristics and advantages of the Beidou system

2024-07-19/ By Admin

　　The Beidou system consists of three parts: space segment, ground segment, and user segment. The space segment consists of a constellation of satellites with different orbital planes, including 3 GEO satellites, 3 IGSO satellites, and 24 MEO satellites. The ground segment includes several ground stations such as the main control station, time synchronization/injection station, monitoring station, and inter satellite link operation management facilities. The user segment includes basic products such as chips, modules, and antennas compatible with other satellite navigation systems, as well as terminal products, application systems, and application services.

　　The Beidou system has the characteristics of mixed constellations, multiple frequency signals, and integrated communication and navigation, and has become a leading satellite navigation and positioning system in the world. Compared with other navigation systems such as GPS, the Beidou system has the characteristics of mixed constellations, multiple frequency signals, and integrated communication and navigation.

　　One is that the Beidou system space segment adopts a mixed constellation composed of three types of orbiting satellites, which has more high orbit satellites and stronger anti occlusion ability compared to other satellite navigation systems, especially in low latitude areas where performance advantages are more obvious.

　　The second is that the Beidou system provides navigation signals at multiple frequency points, which can improve service accuracy through the combination of multiple frequency signals.

　　Thirdly, the Beidou system innovatively integrates navigation and communication capabilities, providing various service capabilities such as positioning and navigation timing, satellite based enhancement, ground-based enhancement, precise single point positioning, short message communication, and international search and rescue.

　　Innovative GEO+IGSO+MEO "Three Orbits" Hybrid Constellation Configuration

　　The Beidou system is a hybrid navigation constellation consisting of three types of orbiting satellites: GEO satellites, IGSO satellites, and MEO satellites.

　　1. GEO satellites are positioned above the equator, with a motion period that is the same as the Earth's rotation period. They are relatively stationary with an orbit altitude of 35786km and an inclination angle of 0 degrees. The coverage area of a single satellite is relatively large, and three satellites can cover most of the Asia Pacific region. The visibility of users within the coverage area reaches 100%. GEO satellites have a high orbit, therefore they have good anti occlusion properties and obvious advantages in applications such as cities, canyons, and mountainous areas.

　　2. The orbit altitude of IGSO satellite is the same as that of GEO satellite, with an inclination angle of 55 degrees and a sub satellite point trajectory of "8". IGSO satellite signals have strong anti occlusion capabilities, especially in low latitude regions where performance advantages are evident. Due to China's location in the northern hemisphere, the obstruction of tall mountains and buildings makes it difficult for users on the north side to receive GEO satellite signals in the equatorial plane. IGSO always covers a certain area on Earth and can be paired with GEO satellites to form a good geometric configuration, which to some extent overcomes the impact of GEO satellites' low elevation angles in high latitude areas and effectively alleviates the problem of the North Slope Effect.

　　3. The MEO satellite has an orbit altitude of approximately 21500km and an inclination angle of 55 degrees. It rotates around the Earth and can achieve global coverage through a network of multiple satellites. The regression characteristic of the Beidou MEO constellation is 13 circles in 7 days.

　　The mixed constellation configuration covers prominent areas globally, with rich functions and high cost-effectiveness. MEO satellite fully supports global coverage and services; The regional constellation composed of GEO satellites and IGSO satellites not only achieves a good geometric configuration for the Asia Pacific region, but also achieves better constellation performance in key areas, shielding areas, etc., significantly enhancing the navigation performance of Beidou in key service areas. GEO satellites not only provide basic positioning, navigation, and timing services, but also carry regional short message communication, precise single point positioning, satellite based augmentation, and other service functions. MEO satellites also carry global short message communication, international search and rescue, and other service functions.