The Military Capabilities and Implications of China's Indigenous Satellite-Based Navigation System

China has orbited a three-satellite constellation for space-based navigation known as Beidou. This article uses the constellation geometry, as determined by the NORAD space-surveillance system and publicly available from NASA, to estimate the accuracy available to a user of the Beidou system. Limited in terrestrial coverage to roughly the Asian subcontinent, this system requires a user either to go through an iterative procedure ill-suited to most military applications or to provide his or her own standard of time by carrying a high-precision clock. The iterative method does provide accuracies comparable to NAVSTAR/GPS over a restricted area of the Earth. Carrying an atomic clock, however, allows the system to be used in a mode that can provide sufficient accuracy to be used on MIRVed Chinese ICBMs en route to the United States and make a significant improvement in accuracy. Surprisingly, those modes of operation do not provide sufficient accuracy for most conventional military users.