Telstra has revealed the addition of almost one million new mobile services in the six months to December 2011, but Sensis revenues plummeted 24 percent in 12 months.
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William Atkins
Monday, 05 February 2007 03:41
The global navigation satellite system (GNSS) is the general name for any series of navigational satellite systems built to provide global coverage from orbit about the Earth. The U.S./GPS is already fully operational in orbit about the Earth, while the E.U./Galileo is not yet operational. The Russians are also building a GNSS, which is called GLONASS (or GLObal NAvigation Satellite System).
The U.S./GPS, E.U./Galileo, and Russian/GLONASS all use satellites that move relative to the Earth’s surface. The Chinese/Beidou will position five of its satellites in geostationary orbit about the Earth, which do not move relative to the Earth’s surface. The other 30 satellites will orbit in similar orbits as the other GNSS countries.
Although the Chinese began investing in the E.U./Galileo project in 2003, its Beidou is expected to be a competitor of the E.U./Galileo project. All GNSSs built by China, the United States, the European Union, and Russia use radio frequencies for its communications.
The Chinese earlier launched three other Beidou satellites in the years 2000 and 2003. Beidou 1A was launched on October 30, 2000; Beidou 1B on December 20, 2000; and Beidou 2A on May 24, 2003. However, this fourth satellite has been the first launched in almost four years. It was launched by a Long March 3A rocket, one of a family of Long March expendable launch system rockets manufactured by the China Academy of Launch Vehicle Technology.
The Beidou Satellite Navigation and Positioning System (Beidou) is named after the Chinese constellation Beidou, which is the equivalent to the Big Dipper in Western Hemisphere countries. Space activities inside China are managed by the China National Space Administration (CNSA).
The Xinhua News Agency, the official news agency in China, has said that the Beidou satellites will allow the calculations of positions on the surface of the Earth as precisely as 10 meters (about 32 feet). According to Xinhua, China is expecting that the Beidou system will provide navigation coverage to China and portions of neighboring countries by 2008.
The English version of the Web site of the China National Space Administration is: http://www.cnsa.gov.cn/n615709/cindex.html.
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