BeiDou-1 is an experimental regional navigation system, which consists of four satellites (three working satellites and one backup satellite). The satellites themselves were based on the Chinese DFH-3 geostationary communications satellite and had a launch weight of 1,000 kilograms (2,200 pounds) each.
বেইডু-১ সিস্টেমে কতগুলো স্যাটেলাইট ব্যাকআপের জন্য ব্যবহৃত হয়?
one