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.
