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this morning, my country will launch the 59th and 60th beidou navigation satellites using the long march 3b carrier rocket and the yuanzheng-1 upper stage from the xichang satellite launch center.

the “three steps” of beidou construction from the beginning to the global network

from the idea proposed in the 1980s to the official launch of the beidou-1 system in 1994, several generations of beidou people have gone through the "three-step" development process of beidou system construction after decades of practical exploration. let's talk about beidou in numbers and learn about the development process of the beidou system from scratch, from active positioning to passive positioning, from serving china to serving asia-pacific, and then to global networking.

the "three-step" approach to beidou system construction is a development route proposed based on my country's actual technological and economic development at different stages.

the first step is to build the beidou-1 system, also known as the beidou satellite navigation test system, to realize satellite navigation from scratch.

in 1994, the construction of the beidou-1 system was officially launched.

in 2000, two geostationary orbit (geo) satellites were launched and the beidou-1 system was completed and put into use.

in 2003, the third geostationary orbit (geo) satellite was launched to further enhance the system performance. the completion of the beidou-1 system took the first exploratory step and initially met the positioning, navigation and timing needs of china and surrounding areas. at that time, an active positioning system was adopted, that is, the user needed to transmit a signal for the system to locate it. this process relied on satellite transponders, so there was a time delay and limited capacity, which could not meet the needs of high dynamics. however, beidou-1 cleverly designed a two-way short message communication function. this integrated communication and navigation design is beidou's original creation. the completion of beidou-1 has enabled china's satellite navigation system to achieve a leap from scratch, and china has become the third country to have a satellite navigation system after the united states and russia.

the second step is to build the beidou-2 system, from active positioning to passive positioning, and provide regional navigation services for the asia-pacific region.

in 2004, the construction of the beidou-2 system was launched. beidou-2 innovatively constructed a medium- and high-orbit hybrid constellation architecture. by 2012, it had completed the launch and networking of 14 satellites. among these 14 satellites, there are 5 geostationary orbit (geo) satellites, 5 inclined geosynchronous orbit (igso) satellites and 4 medium earth orbit (meo) satellites. on the basis of being compatible with the active positioning system of beidou-1, the beidou-2 system has added a passive positioning system, that is, users do not need to transmit signals themselves, but can only receive signals to locate, which solves the user capacity limitation and meets the high dynamic requirements. the completion of the beidou-2 system not only serves china, but also provides positioning, speed measurement, timing and short message communication services for users in the asia-pacific region.

the third step is to build the beidou-3 system, establish “inter-satellite links”, and realize global networking.

in 2009, the construction of the beidou-3 system was launched. by 2020, the global network will be completed and the beidou-3 system will be fully built. the beidou-3 system inherits the two technical systems of active positioning and passive positioning. through the "intersatellite link" - the connection "dialogue" between satellites, it alleviates the difficulty of global network deployment. on the basis of beidou-2, beidou-3 further improves the performance and expands the functions to provide global users with positioning, navigation and timing, global short message communication and international search and rescue services; at the same time, it provides satellite-based augmentation, ground-based augmentation, precise single-point positioning and regional short message communication services in china and surrounding areas.

in 2023, my country launched three more beidou navigation satellites, which are of great significance to supporting the large-scale application of beidou. the medium earth orbit (meo) satellites launched this time will further enhance the reliability of the beidou-3 global satellite navigation system and the performance of services such as positioning, navigation, timing, and global short message communication. while supporting the stable operation of the beidou system and the large-scale application of beidou, they will also conduct relevant experiments for the next generation of beidou navigation satellite technology upgrades.

before 2035, my country will build and improve a more ubiquitous, more integrated and more intelligent comprehensive space-time system.

source cctv news client

editor: li tuo

process editor: ma xiaoshuang