BeiDou

The BeiDou Navigation Satellite System (BDS; Chinese: 北斗卫星导航系统; pinyin: běidǒu wèixīng dǎoháng xìtǒng) is a satellite-based radio navigation system owned and operated by the China National Space Administration. It provides geolocation and time information to a BDS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more BDS satellites. It does not require the user to transmit any data and operates independently of any telephonic or Internet reception, though these technologies can enhance the usefulness of the BDS positioning information. The current service, BeiDou-3 (third-generation BeiDou), provides full global coverage for timing and navigation, along with Russia's GLONASS, the European Galileo, and the US's GPS. It comprises satellites in three types of orbits: 24 in medium Earth orbit (global coverage), 3 in inclined geosynchronous orbit (Asia–Pacific coverage), and 3 in geostationary orbit (China coverage). The BeiDou-3 system was fully operational in July 2020. In 2016, BeiDou-3 reached millimeter-level accuracy with post-processing from a nationwide reference station network. In 2023, the International Civil Aviation Organization recognized the BeiDou system as a global standard for commercial aviation. Predecessors included BeiDou-1 (first-generation BeiDou), consisting of three satellites in a regional satellite navigation system. Since 2000, the system has mainly provided navigation services within China. In December 2012, as the design life of BeiDou-1 expired, it stopped operating. The BeiDou-2 (second-generation BeiDou) system was also a regional satellite navigation system containing 16 satellites, including 6 geostationary satellites, 6 inclined geosynchronous orbit satellites, and 4 medium earth orbit satellites. In November 2012, BeiDou-2 began to provide users with regional positioning services in the Asia-Pacific region. Within the region, BeiDou is more accurate than GPS. In 2015, fifteen years after the satellite system was launched, it was generating a turnover of $31.5 billion per annum for major...