China launches penultimate BeiDou navigation satellite
The penultimate satellite required to complete the BeiDou global positioning, navigation, and timing (PNT) system
was launched from the Xichang satellite launch centre in southwestern China on 9 March.
The BeiDou system
has been developed in three phases.
The first phase
was largely experimental with the first satellite placed in orbit in October 2000.
The second phase
provided a regional navigation system and was declared operational in 2012.
The third phase
provides global coverage, with the launch of the final satellite in the network planned for May.
A total of 54 BeiDou-2 and
BeiDou-3 satellites
have been launched since 2007,
although these include some platforms that provide a degree of redundancy and others used to fully develop the BeiDou-3 system.
Jane’s 360
https://www.janes.com/article/94842/china-launches-penultimate-beidou-navigation-satellite
China’s new navigation system is nearly complete with penultimate Beidou satellite launch | Space
https://www.space.com/amp/china-long-march-3b-rocket-launches-54th-beidou-satellite.html