About Compass/Beidou

China launched its second GEO satellite in spring 2009 for its Compass (Beidou 2) Navigation Satellite System (CNSS). The April 15 launch was the first of 10 planned through the end of 2010.

China intends to provide first a regional capability for Compass/Beidou, followed by completion of its full 30-MEO, 5-GEO constellation after 2015 and before 2020.

The space segment of CNSS will consist of 5 geostationary earth orbit (GEO) and 30 MEO satellites transmitting signals on the following carrier frequencies: 1195.14–1219.14MHz, 1256.52–1280.52MHz, 1559.05–1563.15MHz and 1587.69–1591.79MHz. Some of the signals overlay the Galileo PRS band and to a lesser extent the GPS M-code.

As of 2009, little progress has occurred in talks between the European Commission
(EC) and the Chinese government that seek to avoid the overlay of
Compass signals on two E1 (L1) bands planned for Galileo’s
security-oriented Public Regulated Service (PRS).

Although initiated by China’s military forces, a recently established China Satellite Navigation Project Center (CSNPC) reportedly will take charge of the research, building, and management of CNSS.

The Compass ground segment consists of a master control station, upload station, and monitor station. COMPASS/Beidou user terminals are intended to be “compatible” with GPS, GLONASS, and Galileo receivers, according to Chinese officials.

Two kinds of service will be provided: an open service, which is designed to provide positioning accuracy within 10 meters, velocity accuracy within 0.2 meters per second, and timing accuracy within 50 nanoseconds; and an “Authorized Service,” which will offer “safer” positioning, velocity, timing communication services, and integrity information for authorized users.