Beidou M4

Description

Beidou M4, a Chinese navigation satellite, was launched from Xichang on 29 April 2012 at 20:50 UT by a Long March 3B rocket. China launched two navigation satellites on this mission, Beidou M3 and Beidou M4. This is the first time China launched a dual-satellite primary payload into high-altitude orbit. A dual-payload adapter was developed to launch the satellites one on top of the other inside the Long March nose fairing. Both satellites, Beidou M4 and Beidou M3, are part of the Beidou navigation constellation, also known as the Compass Navigation Satellite System (CNSS), China's second-generation satellite navigation system. CNSS is capable of providing continuous, real-time passive 3D geo-spatial positioning and speed measurement. The system will be dual use, based around a civilian service that will provide an accuracy of 10 meters in the user position, with the military and authorized user's service, providing higher accuracies. The long-term goal is to develop a global navigation satellite network consisting of a constellation of 35 vehicles by 2020. The satellites have a lifespan of 12 to 15 years.