Tuesday, December 27, 2011

China's Beidou Satellite Navigation System Operational



China's indigenous satellite navigation system called Beidou is up and running for people in and around China. It started providing initial operational services, including positioning, navigation and timing Tuesday.

The 10th satellite of the network was launched back on December 2nd, putting the finishing touches on the basic structure of the system.

Tests were carried out for the past six months.

[Yang Qiangwen, China Satellite Navigation System Management Office]:
"Firstly we carried out comprehensive tests on all the satellites, including all key machines and equipment, to ensure they can provide continuous service. Secondly, we optimized the positions of all the satellites to ensure the best conditions for operation."

Six more satellites will be launched in 2012 to further expand the service area of the Beidou system to most parts of the Asia-Pacific region.

[Ran Chengqi, Management Office, China Satellite Navigation System]:
"Preliminary tests show that the basic positioning and navigation system of Beidou has reached the set standards and we have officially moved from the test system to the working system. This step marks the transition from construction to application."

The global satellite positioning and navigation system will be completed in 2020, with 30 satellites orbiting the earth.

Started in 2000, the Beidou satellite navigation system is designed to make China independent of the Global Positioning System (GPS).

Sunday, December 18, 2011

China is retiring J-7 jet from front line service



in 2009, China finally stopped the production of J-7G, the last variant of Mig-21 jet.

China has officially withdrawn its MiG-21 clone (the J-7) from first line service. This comes as no surprise. In the last four years China has more than doubled the number of modern combat aircraft (J-10, J-11, Su-27, Su-30, and J-8F) from 500 to over 1,200. Four years ago China relied mainly on some 2,000 locally built copies of Russian MiG-19s (J-6) and MiG-21 (J-7). There are still several hundred bombers mostly Russian knockoffs. Normally, the actual number of Chinese aircraft is a state secret. However, thanks to the ability of Chinese to move freely throughout the country and access to the Internet it's possible to locate and count all the air force units in the country. That shows a current force that is rapidly changing from one that is mostly MiG-21s and MiG-19s, to one composed of much more capable aircraft. China is buying and building a lot of the Russian Su-27s and Su-30s (the latter an upgrade of the former.) But new, home grown designs, like the J-20 are also showing up.

Another reason for withdrawing the J-7 to secondary regions (where modern jets are unlikely to be encountered) is the inability to use J-7s for a lot of training. That's important because China is revising its combat pilot training program. The existing system takes ten years of academic and flight training. The new program cuts that to 5-7 years, while increasing flight hours by over 40 percent. This is more in line with Western methods, while the existing system owes more to the one the Russians developed during the Cold War. The new system puts more emphasis on trainee pilots demonstrating combat flying skills before they can graduate. Cold War era Russian aircraft designs, like the MiG-21, were not designed for the heavy use required for Western style pilot training.

The new training program is actually an evolution of the need for new training methods to prepare pilots to handle the more modern aircraft. Training for pilots of these new fighters has been more intense than for any previous aircraft. In addition, China is also holding training exercises directed at fighting other modern fighters, like those flown by Taiwan, Japan, and the United States. China is not keeping much of this secret and that is apparently sending a message to potential foes.

China has long been the largest user of the MiG-21 in the form of their J-7 clone. China still exports J-7s but has been rapidly retiring the ones remaining in Chinese service. The J-7 was, in many ways, the most advanced version of the MiG-21, as the Chinese kept improving their J-7 design. Over 10,000 Mig-21s and J-7s have been produced in the last sixty years, making this the most widely manufactured jet fighter of the last century (during World War II there were several propeller driven fighters that were produced in greater numbers.) The MiG-21 looked fearsome but it was a bust in combat, getting shot down more often than not. Russia still had 186 Mig-21s in service when the Soviet Union dissolved in 1991s. These MiG-21s were officially retired a few years later. India, the last major user of the MiG-21, is in the process of retiring them as well.

Saturday, December 10, 2011

China navy to exercise in Western Pacific



China has said it will conduct "routine" naval exercises in the Pacific Ocean, in the week after a major diplomatic campaign by US President Barack Obama to assert the United States as a Pacific power.

The defence ministry said the exercises, to be held later this month, did not target any particular country, but the announcement comes against a background of growing tensions over maritime disputes in the Asia-Pacific region.

Obama, who has dubbed himself America's first Pacific president, said last week the United States would deploy up to 2,500 Marines to Australia and tighten air force cooperation, a move seen as a response to China's growing regional might.

China's freedom of navigation "shall not be subject to any form of hindrance", the defence ministry said in a brief statement late Wednesday announcing the naval exercises in the western Pacific.

"This is a routine drill arranged under an annual plan, does not target any particular country or target, and complies with relevant international laws and international practice," it added.

Obama flew home Saturday after a seven-day tour of Pacific nations during which he took in a trio of summits and announced greater military involvement in the region.

"Here is what this region must know. As we end today's wars, I have directed my national security team to make our presence and missions in the Asia-Pacific a top priority," the US president announced during a visit to Australia.

Washington's new diplomatic campaign to assert itself as a Pacific power has alarmed China, which sees initiatives like stationing Marines in Australia as intruding into its sphere of influence.

China's Premier Wen Jiabao has warned against interference by "external forces" in regional territorial disputes including in the South China Sea, a strategic and resource-rich area where several nations have overlapping claims.

China claims all of the maritime area, as does Taiwan, while four Southeast Asian countries declare ownership of parts of it, with Vietnam and the Philippines accusing Chinese forces of increasing aggression there.

The competing claims have led to periodic outbreaks of tension between China and its neighbours in recent years, including with the Philippines and Vietnam in recent months, and with Japan in late 2010.

Asia-Pacific leaders held talks on the disputed territories at a summit Saturday, in a major diplomatic coup for the United States, which had pushed for the topic to be raised, despite objections from Beijing.

China's official comments on Obama's trip were muted, but state news agency Xinhua said Asian suspicions would be raised by the plan to base troops in Australia and by US Secretary of State Hillary Clinton's declaration that the 21st century will be "America's Pacific century".

"If the United States sticks to its Cold War mentality and continues to engage with Asian nations in a self-assertive way, it is doomed to incur repulsion in the region," the agency said.

"The hard fact is that the Pacific Ocean belongs to all countries sharing its shores, not just the United States."

China's People's Liberation Army, the largest armed force in the world, is primarily a land force, but the navy is playing an increasingly important role as Beijing grows more assertive about its territorial claims.

Earlier this year, the Pentagon warned that Beijing was increasingly focused on its naval power and had invested in high-tech weaponry that would extend its reach in the Pacific and beyond.

Recent trials of China's first aircraft carrier underlined the scale of Beijing's naval ambitions, sparking jitters in the United States and Japan.

China, which publicly announced around 50 separate naval exercises in the seas off its coast over the past two years -- usually after the event -- says its military is only focused on defending the country's territory.

Thursday, December 1, 2011

China breaks record with Long March 3A launch of another BeiDou-2 satellite



A record breaking 16th successful launch of the year for China took place at 21:07 UTC on Thursday, when a Long March 3A (Chang Zheng-3A) launch vehicle orbited a new navigation satellite – another for the BeiDou-2 Compass satellite navigation range – from the Xichang Satellite Launch Center, in Sichuan Province.

China’s Record:

This launch was the 16th successful orbital launch this year for China, breaking the previous launch record of 15 successful missions in 2010. Taking into account the launch failure on August 18th, this was the 17th space launch for China this year.

The satellite that was orbited is the fifth BeiDou-2 IGSO (Inclined GSO) satellite of the system. The satellites were developed in the basis of the DFH-3B satellite platform and have a lifespan of eight years.

This constellation of Compass satellites will consist of 35 vehicles, including 30 MEO (21,500 km orbits) and IGSO (inclined at 55 degrees) satellites and five GSO satellites.

The Compass Navigation Satellite System (CNSS) is China’s second-generation satellite navigation system approved by the Chinese government in 2004, and is capable of providing continuous, real-time passive 3D geo-spatial positioning and speed measurement.

The system was initially used to provide high-accuracy positioning services for users in China and its neighboring regions, covering an area of about 120 degrees longitude in the Northern Hemisphere. The long-term goal is to develop a global navigation satellite network similar to the GPS and GLONASS by 2020.

The system will have two kinds of services: a civilian service that will give an accuracy of 10 meters in the user position, 0.2 m/s on the user velocity and 50 nanoseconds in time accuracy; and the military and authorized user’s service, providing higher accuracies. The first phase of the project will see the coverage of the Chinese territory but in the future the Compass constellation will cover the entire globe.

The satellites transmit signals on the: 1195.14-1219.14MHz, 1256.52-1280.52MHz, 1559.05-1563.15MHz and 1587.69-1591.79MHz, carrier frequencies.

The previous BeiDou-2 ‘Compass’ launch took place on July 26 when a Chang Zheng-3A orbited the ‘Compass-I4′ (37763 2011-038A) satellite.

This was the 22nd flight of the CZ-3A Chang Zheng-3A launch vehicle. The CZ-3A is a three-stage liquid launch vehicle, which has inherited the mature technology of the CZ-3 Chang Zheng-3. An upgraded liquid hydrogen and liquid oxygen cryogenic third stage has been developed to enable CZ-3A performing greater geostationary transfer orbit (GTO) capability.

The CZ-3A is equipped with a more flexible and sophisticated control system which supports substantial attitude adjustments to orient the payloads before spacecraft separation and provides adjustable satellite spin-up rotation rate. It has paved the way for the development of CZ-3B Chang Zheng-3B and CZ-3C Chang Zheng-3C, and become the basic type of GTO launch vehicles.

The CZ-3A is mainly used for GTO missions; it also can be used for LEO, SSO and polar orbit missions, as well as dual-launch and multiple-launch missions. The launch capacity of the CZ-3A to GTO is 2,650 kg, the lift-off mass is 241,000 kg, the overall length is 52.5 meters, the diameter of first stage and second stage is 3.35 meters, the diameter of third stage is 3.0 meters, and the maximum fairing diameter is 3.35 meters.

The first stage and second stage of CZ-3A employ storable propellants, i.e. unsymmetrical dimethy1 hydrazine (UDMH) and nitrogen tetroxide (N­2O4), and the third stage uses cryogenic propellants, i.e. liquid hydrogen (LH2) and liquid oxygen (LOX).

On the first stage the CZ-3A uses a DaFY6-2 engine with 2961.6 kN of thrust, while the second stage is equipped with a DaFY20-1 main engine (742 kN) and four DaFY21-1 vernier engines (11.8 kN each). The third stage is equipped with two YF-75 engines (78.5 kN each).

The fairing diameter of the CZ-3A is 3.35 meters and has a length of 8.89 meters.

CZ-3A consists of rocket structure, propulsion system, control system, telemetry system, tracking and safely system, coast phase propellant management and attitude control system, cryogenic propellant utilization system, separation system and auxiliary system, etc.

The launch success rate of CZ-3A is 100 percent since its maiden flight on February 8, 1994 when it successfully launched two experimental satellites (the Shi Jian-4 and the Kua Fu-1, a DFH-3 model). And it was awarded the “Gold Launch Vehicle” title by China Aerospace Science and Technology Corporation in June 2007.

This was the 153rd successful Chinese orbital launch, the 153rd launch of a Chang Zheng launch vehicle, the 8th launch from Xichang in 2011 and the 67th orbital launch from Xichang.

The Xichang Satellite Launch Centre is situated in the Sichuan Province, south-western China and is the country’s launch site for geosynchronous orbital launches.

Equipped with two launch pads (LC2 and LC3), the centre has a dedicated railway and highway lead directly to the launch site. The Command and Control Centre is located seven kilometers south-west of the launch pad, providing flight and safety control during launch rehearsal and launch.

Down range Tracking and Control stations of the launch center are located in Xichang City and Yibin City of Sichuan Province, and Guiyang City of Guizhou Province. Each of them houses tracking and measurement equipment for the powered phase of a launch vehicle flight.

Other facilities on the Xichang Satellite Launch Centre are the Launch Control Centre, propellant fueling systems, communications systems for launch command, telephone and data communications for users, and support equipment for meteorological monitoring and forecasting.

During 1993-1994 Xichang underwent extensive modernization and expansion, in part due to the requirements of the CZ-3 launcher family and in part to meet commercial customer needs.

The first launch from Xichang took place at 12:25UTC on January 29, 1984, when the CZ-3 Chang Zheng-3 (CZ3-1) was launched the Shiyan Weixing (14670 1984-008A) communications satellite into orbit.

Before the end of the year China plans two more launches. The launch of the NigComSat-1R communications satellite for Nigeria is schedule to take place on December 19. Launched by a CZ-3B/E Chang Zheng-3B/E rocket from Xichang, this satellite will replace the NigComSat-1 satellite that lost power from the southern solar array and latter failed in November 2008 due to a technical error of the satellite’s northern solar array.

The other launch schedule for December will orbit the ZiYuan-1 (2C) Earth resource satellite using a Chang Zheng-4B launch vehicle from Taiyuan.