BeiDou User Segment

COMPASS
Title	BeiDou User Segment
Author(s)	GMV
Level	Basic
Year of Publication	2011

The Compass Navigation Satellite System (CNSS), also named BeiDou-2, is China’s second-generation satellite navigation system that will be capable of providing positioning, navigation, and timing services to users on a continuous worldwide basis.

Although the upgrade of its regional navigation system towards a global solution started in 1997, the formal approval by the Government of the development and deployment of BeiDou-2/CNSS was done in 2004. The system is currently under development evolving from a regional system called BeiDou-1, and in the first phase will provide high-accuracy positioning services for users in China and its neighboring regions by 2012. In a second stage, the system will evolve to provide global navigation services by 2020, similarly to the GPS, GLONASS or Galileo systems.

As of August 2011, nine satellites for Compass have been launched, the first eight of which completed the deployment foreseen for the first phase of BeiDou-2.

COMPASS User Segment

The COMPASS User Segment consists of COMPASS/Beidou user terminals, which receive Compass navigation signals, determine pseudoranges (and other observables) and solve the navigation equations in order to obtain their coordinates. A COMPASS receiver is a device capable of determining the user position, velocity and precise time (PVT) by processing the signal broadcasted by COMPASS satellites. Any navigation solution provided by a GNSS Receiver is based on the computation of its distance to a set of satellites, by means of extracting the propagation time of the incoming signals traveling through space at the speed of light, according to the satellite and receiver local clocks.

In June 2011, the system has completed the ground segment commissioning, including the test section of the user terminal development. There is also an international cooperation in terms of Compatibility and Interoperability between BeiDou and other GNSSs. The BeiDou ICD Document (V1.0) is expected to be published in 2011.

Applications

GNSS applications are all those applications that use GNSS signals to collect position, velocity and time information to be used by the application. For instance, the position and velocity provided by a COMPASS user terminal may be used for different kinds of applications (civil, military, scientific) such as:

• Fishery: Fishermen safety of life, Oceanic and economic security, Protection of marine resources and sovereignty: 14000 fisher users were reported and more than 500 vessel rescue and costal alarm systems have been equipped with BeiDou terminals;
• Disaster Prevention and Mitigation: improvement of rescue response and decision-making capability due to rapid and timely disaster alert, rescue command scheduling and rapid emergency communication. BeiDou terminals were used in the operations that followed the earthquakes in Wenchuan (Sichuan Province) and Yushu (Qinghai Province);
• Timing: Beidou/GPS multi-mode time synchronization devices with embedded Beidou/GPS timing module, with a reported synchorinization accuracy better than 100 ns;
• Other applications include Transportation, Water conservancy, Meteorology, Forest Fire Prevention, Soil Monitoring and Coal Mine Safety Monitoring.

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