After sending in this year three satellites under BDS navigation system China just has announced about positive results of operational tests.
China space industry is well known of its dynamic and pace of development. Impressive achievements made in a very short period of time and wide range of activities from commercial launch systems through manned space missions to scramjet spaceplanes are undoubtedly. So it was quite surprising when China decided to join to Galileo program in 2004 and abandoning development of their Beidou Navigation system. But in the end again China decided to rely on own solutions, independently of foreign influences. Again it happened sooner than later.
History of developing Chinese navigation system is not as old as GPS or Glonass, but still seems longer than it is usually considered. First concept of national satellite navigation system was created in eighties - it was time in China, when huge change in way in thinking about economy and space program had begun. During these years first steps of commercializing of space industry took place, for example first Long March rockets designed especially for foreign customers were developed. It was sure, that sooner or later satellite navigation will be something common like satellite television. In spite of fact that China had no experience in navigation systems (In USA establishing GPS was preceded by couple strictly military navigation systems utilized by U.S. Navy) realistic deadline was set - term of first working system available for national customers was appointed on year 2000. Main founder of Chinese satellite navigation was Chen Fangyun, member of a standing committee of the Chinese Academy of Sciences. First idea proposed in 1983 involved creating experimental system based on two satellites. On the basis of this assumption works continued until 1994 when Government officially ratified Beidou Satellite Positioning and Navigation system program. After six years China launched first satellites for experimental phase of program - BD-1A on 30 October 2000 and BD-1B on 20 December 2000. Satellites were developed by China Academy of Space Technology (CAST) as medium weight (2200 kg) satellites with operational life at 5 years. Third satellite which was necessary for starting system (and also necessary as backup satellite) was launched in 2003. As launch vehicles in all three missions Long March 3A rocket was utilized, and launches were performing from Xichang Satellite Launch Center. In 2004 China announced about starting cooperation under Galileo program (ESA navigation system) and further investing €230 million. It seemed clear, that Beidou will remain experimental system, or it will be limited only to military purposes with no intention of developing into civilian and commercial venture. Further rare missions with Beidou satellites were confirming such way of thinking; fourth satellite was launched on 2007 (BD-1D on atop of Long March 3A from Xichang Center). In the meantime China gave to public information about technical possibilities of Beidou phase one - accuracy at 10 meters and speed at 0.2 m/s for open service. Comparing to existing Glonass, Beidou seemed to be promising system; remembering the fact that it was only in experimental phase. Glonass was offering accuracy within range 5 to 10 meters and speed at 0.1 m/s. As far as GPS and Galileo were concerned - GPS standard accuracy was at 15 m and Galileo at 4 meters. Also in 2007 first next generation Beidou satellite was launched (long March 3A rocket/Xichang Satellite Launch Center) - BD-2 M1. Still based on DFH-3 bus was able to remain operational for eight years (instead five in first generation). Seeing growing potential in their system, China decided to abandon Galileo in 2008 and develop Beidou as potential competitor on Asian market with objective to become worldwide navigation system. Since that moment, Beidou started phase 2. In 2009 China started to extend constellation of Beidou satellites with BD-2 M (tested after first launch in 2007) and BD-2 G. In years 2009-2012 nine BD-2 M satellites were launched (Long March 3A in 2010-2011 and Long March 3B in 2012, all launches were performed from Xichang Satellite Launch Center) and six BD-2 G (Long March 3C, Xichang Satellite Launch Center). In 2012 old Beidou system was decommissioned and officially replaced with Beidou-2.
Beidou-2 will be based on constellation of 35 satellites and will be fully operational in 2020. At the moment second generation satellites are operating: BD-2 M and BD-2 G. Both types are designed to remain operational for eight years. M satellites weigh at 2200 kg and have power consumption at 3000 W. G type have weight at 4,600 kg and power consumption at 6800 W. BD-2 G is equipped with two types of payload: RDSS (Radio Determination Satellite Service) which consists of high-power S band transponder, an L band low-noise amplifier, frequency generator, a large L/S band antenna, and a C band antenna. Second instrument is RNSS (Radio Navigation Satellite Service) which is combination different devices like: atomic clock, an L band transmitter, signal processor, transmitter antennas array, an L band uplink receiver, laser corner-cube reflector for orbit determination, and multilateration unit. Difference between them is similar to difference between types of satellites in Galileo system. M type satellites are responsible for testing and validating signal send from G type satellites. Beidou-2 is utilizing satellites injected into both GEO and intermediate Earth orbit. System was fully operational in Asia (covering area between longitude 55°E to 180°E and from latitude 55°S to 55°N) since 2012. Operating worldwide was started with launching in 2015 three satellites of third generation - BD-3 I (Long March 3B, Xichang Satellite Launch Center). Next five satellites from third generation called BD-3 G will be placed on GEO in following years. Last class of satellites under Beidou-2 system is BD-3 M. It will be launched 27 satellites from this series; they are based on smaller bus called Navigation Satellite Bus. Weight of BD-3 M is at 1,014 kg with 280 kg of payload (RNSS) and power consumption at 1500 W. Satellites will be placed at Medium Earth orbit at altitude of 22000 km.
Beidou-2 will be available for civilian and military customers. Free of charge civilian version will offer 10 m accuracy, military version - 10 cm accuracy. For the moment in spite of Chinese Army, military version is utilized by Pakistan Armed Forces. It is great success of Chinese space industry; firstly because of selling navigation system for foreign customer just after finishing operational testing. Second, because it means that both Glonass and GPS had lost competition - Pakistan is important customer for military industry. Due the permanent conflict with India for Cashmere and less developed own space program, Pakistan is also promising partner in space ventures. China seems to have a pole position in Pakistan in that matter. Corporation under Pakistan space program with China started in early nineties when first Pakistan satellite Badr-I was launched from China (first Pakistan remote sensing satellite scheduled on 2018 will be probably also launched with Chinese launch vehicle). Beidou-2 success seems to be confirmation of Chinese supremacy on Asian space military market. As far as civilian customers it is good to remind words of secretary-general of the Global Navigation Satellite System, Mr. Miao Qianjun from autumn 2015:
"The system will help create 200 billion yuan ($31.5 billion) in turnover for its customers this year,"
Today when 70% of China population is using smartphones equipped with satellite navigation receivers this market is very promising. Competition in Asian navigation system market is limited to Indian national navigation system operating only in India and Japanese Quasi-Zenith Satellite System (QZSS) is rather local upgraded GPS version providing wider service of data transfer than fully independent navigation system. It seems that China again stroke the home.