RIASSUNTO
The BeiDou Navigation Satellite System (BDS) is a global navigation satellite system to be developed independently by China. It will provide positioning, navigation, and timing services with a global coverage by 2020. It can be used for transport, weather forecast, fishing, forestry, telecommunications, hydrological monitoring, and mapping. The service modes are the open service (OS) and the authorized service (AS). The open service is provided free of charge with positioning accuracy of 10 meters, velocity accuracy of 0.2 m/s, and timing accuracy of 50 nanoseconds. The authorized service is provided with a more secure and higher level of integrity. Beside that AS also provides communication services.