The BeiDou Navigation Satellite System is China’s version of GPS. Uniquely, it’s made up of two separate satellite constellations and it’s been claimed that, with post-processing, it’s accurate to within millimeters.
The BeiDou Navigation Satellite System (BDS) (Chinese: 北斗卫星导航系统; pinyin: Běidǒu Wèixīng Dǎoháng Xìtǒng[pèitòu wêiɕíŋ tàuxǎŋ ɕîtʰʊ̀ŋ]) is a Chinese satellite navigation system. It consists of two separate satellite constellations. The first BeiDou system, officially called the BeiDou Satellite Navigation Experimental System and also known as BeiDou-1, consisted of three satellites which, beginning in 2000, offered limited coverage and navigation services, mainly for users in China and neighboring regions. BeiDou-1 was decommissioned at the end of 2012. On 23 June 2020, the final BeiDou satellite was successfully launched, the launch of the 55th satellite in theBeidou family. The third iteration of this Satellite System promises to provide global coverage for timing and navigation, offering an alternative to Russia’s GLONASS, the European Galileo positioning system, and America’s GPS.
The second generation of the system, officially called the BeiDou Navigation Satellite System (BDS) and also known as COMPASS or Bei Dou-2, became operational in China in December 2011 with a partial constellation of 10 satellites in orbit. Since December 2012, it has been offering services to customers in the Asia-Pacific region.
In 2015, China launched the third generation BeiDou system (BeiDou-3) for global coverage. The first BDS-3 satellite was launched on 30 March 2015. On 27 December 2018, BeiDou Navigation Satellite System started providing global services. The 35th and the final satellite of BDS-3 was launched into orbit on 23 June 2020. It was said in 2016 that BeiDou-3 will reach millimeter-level accuracy (with post-processing).