In 2006, China announced plans to develop a global navigation system composed of 5 satellites in geostationary orbit and 30 in medium Earth orbit (12 hour, 55 deg. inclination, 21,000 km altitude circular orbits). The first medium orbit satellite was launched from Xichang on April 14th, 2007 and there are plans to launch 7 more satellites in 2008. This satellite system is the second generation of the Big Dipper (Beidou 北斗) navigation system, sometimes called the Compass navigation system. Using similar technology to the Navstar, Glonas, and Galileo navigations systems, a passive receiver collects signals from medium orbit satellites and calculates a position within an accuracy of 10 meters, velocity of 0.2 meters per second, and timing of 50 nanoseconds. Free service will be provided to users in China. Higher accuracy and communications capability will be available for licensed and military users.

The original experimental Big Dipper system was composed of three satellites (Twinsat with one backup) launched between 2000 and 2003. Covering East and Southeast Asia, Beidou-1 was an active system requiring dual-way transmission between user and control station via satellite, providing an accuracy within 20 meters and some communications capability. Early attempts to commercialize the system included a joint venture in 2000 with Canada Novatel to form BDStar Navigation, providing the Beidou I Information Service System. As part of the 863 Plan, the Ministry of Science and Technology in 2006 began a Beidou Satellite Integrated Information Application Service for various rural and oceanographic uses. For example, see the Beidou navigation products offered on the China Aerospace Sceience and Technology Corporation website (pictures are from 2005). (http://www.spacechina.com/cpyjs_mycy_Details.shtml?recno=34454)

The expansion and opening of the Beidou program into a commercial and military global navigation system will have significant impact on both EU Galileo and US GPS-3 systems. It is perhaps the final nail in the coffin for the fledgling Galileo project, which has been plagued by funding (already 2.5 billion euros in debt), commercial, and political problems. China, having learned what it needed, has backed away from its 230 million euro pledge and involvement. By offering free service to China and possibly other countries in East Asia, Beidou-2 will kill Galileo’s attempts to enter a key market. By using a signal frequency close the to US M-code used by GPS-3, Beidou-2 will also force the US to find more flexible and robust means of overcoming interference, especially in any potential East Asian theater.

Links:

http://www.spacechina.com

http://www.spacetoday.org/China/ChinaHistory.html

www.sinodefence.com

www.astronautix.com/craft.beidou.htm

Beidou Chronology (from www.astronautix.com/craft.beidou.htm)
• 2000 December 20 - Beidou 1B - Launch Site: Xichang. Launch Vehicle: CZ-3A. Mass: 2,200 kg (4,800 lb). Perigee: 35,753 km (22,215 mi). Apogee: 35,821 km (22,258 mi). Inclination: 0.00 deg. Period: 1,436.10 min.
Second Beidou geosynchronous navigation satellite. The CZ-3A rocket's third stage put Beidou in geostationary transfer orbit at around 1642 GMT. The Beidou satellite was based on the DFH-3 comsat and had a mass of around 2200 kg including its FY-25 solid apogee motor. On December 25 Beidou was in a 190 x 41870 km x 25.0 deg transfer orbit. The launch of this second Beidou completed the prototype two-satellite navigational system which was to provide positional information for highway, railway and marine transportation. Positioned in geosynchronous orbit at 80 deg E, still maintaining its position within 0.1 deg as of 2007.
• 2000 October 30 - Beidou 1A - Launch Site: Xichang. Launch Vehicle: CZ-3A. Mass: 2,200 kg (4,800 lb). Perigee: 35,772 km (22,227 mi). Apogee: 35,803 km (22,246 mi). Inclination: 0.10 deg.
Beidou was China's first experimental navigation technology satellite, developed by CAST/Beijing. The satellite was placed in an initial 195 x 41889 km x 25.0 deg orbit geostationary transfer orbit before entering its final geosynchornous orbit at around 0500 GMT on November 6. Stationed at 140 deg E, still maintaining its position within 0.1 deg as of 2007.
• 2003 May 24 - Beidou 2A - Launch Site: Xichang. Launch Vehicle: CZ-3A. Mass: 2,200 kg (4,800 lb). Perigee: 35,760 km (22,220 mi). Apogee: 35,836 km (22,267 mi). Inclination: 0.30 deg. Period: 1,436.70 min.
Navigation technology satellite, joined Beidou 1A and 1B launched in December 2000. This third satellite was considered a back-up element, Positioned at 110 deg E, still maintaining its position within 0.1 deg as of 2007.
• 2007 April 12 - Beidou 5 - Launch Site: Xichang. Launch Vehicle: CZ-3A. Mass: 2,200 kg (4,800 lb). Perigee: 21,519 km (13,371 mi). Apogee: 21,544 km (13,386 mi). Inclination: 55.30 deg. Period: 773.40 min.
The fifth Beidou satellite, but the first in the 12-hour, 55 deg inclination MEO portion of the constellation. All previous launches had been to populate the geostationary portion of the system.
• 2007 February 2 - Beidou 2A - Launch Site: Xichang. Launch Vehicle: CZ-3A. Mass: 2,200 kg (4,800 lb). Perigee: 35,326 km (21,950 mi). Apogee: 36,248 km (22,523 mi). Inclination: 6.20 deg. Period: 1,436.10 min.
Fourth Beidou satellite. It did not reach geostationary orbit until early April following deployment problems with its solar panels and reports of US detection of a debris cloud at the time of the original expected apogee firing.
Beidou-2 (from Sinodefense.com)
Compass-M1 on 14 April 2007. A CZ-3A space launch vehicle carrying the satellite lifted off from XSLC at 20:11 GMT on 13 April 2007 (04:11 local time on 14 April 2007). The satellite will operate at an altitude of 21,500km orbit.