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56e103f6e3433e1400422ab1 | BeiDou_Navigation_Satellite_System | In April 2007, the first satellite of BeiDou-2, namely Compass-M1 (to validate frequencies for the BeiDou-2 constellation) was successfully put into its working orbit. The second BeiDou-2 constellation satellite Compass-G2 was launched on 15 April 2009. On 15 January 2010, the official website of the BeiDou Navigation Satellite System went online, and the system's third satellite (Compass-G1) was carried into its orbit by a Long March 3C rocket on 17 January 2010. On 2 June 2010, the fourth satellite was launched successfully into orbit. The fifth orbiter was launched into space from Xichang Satellite Launch Center by an LM-3I carrier rocket on 1 August 2010. Three months later, on 1 November 2010, the sixth satellite was sent into orbit by LM-3C. Another satellite, the Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit) satellite, was launched from the Xichang Satellite Launch Center by a Long March-3A on 1 December 2011 (UTC). | What is the the first satellite for the BeiDou-2 system called? | {
"answer_start": [
35
],
"text": [
"Compass-M1"
]
} | 0.003483 |
56e0fdc8231d4119001ac55a | BeiDou_Navigation_Satellite_System | The first satellite, BeiDou-1A, was launched on 30 October 2000, followed by BeiDou-1B on 20 December 2000. The third satellite, BeiDou-1C (a backup satellite), was put into orbit on 25 May 2003. The successful launch of BeiDou-1C also meant the establishment of the BeiDou-1 navigation system. | What was the name of the third satellite launched for the system? | {
"answer_start": [
51
],
"text": [
"BeiDou-1C"
]
} | 0.003648 |
56e10ac2cd28a01900c674b9 | BeiDou_Navigation_Satellite_System | BeiDou-2 (formerly known as COMPASS) is not an extension to the older BeiDou-1, but rather supersedes it outright. The new system will be a constellation of 35 satellites, which include 5 geostationary orbit satellites for backward compatibility with BeiDou-1, and 30 non-geostationary satellites (27 in medium Earth orbit and 3 in inclined geosynchronous orbit), that will offer complete coverage of the globe. | What was the BeiDou-2 system previously known as? | {
"answer_start": [
26
],
"text": [
"COMPASS"
]
} | 0.003685 |
56e1161ccd28a01900c6757c | BeiDou_Navigation_Satellite_System | Compass-M1 is an experimental satellite launched for signal testing and validation and for the frequency filing on 14 April 2007. The role of Compass-M1 for Compass is similar to the role of the GIOVE satellites for the Galileo system. The orbit of Compass-M1 is nearly circular, has an altitude of 21,150 km and an inclination of 55.5 degrees. | What is the altitude of the Compass-M1 satellite? | {
"answer_start": [
85
],
"text": [
"21,150 km"
]
} | 0.003903 |
56e1030ae3433e1400422a9d | BeiDou_Navigation_Satellite_System | In February 2007, the fourth and last satellite of the BeiDou-1 system, BeiDou-1D (sometimes called BeiDou-2A, serving as a backup satellite), was sent up into space. It was reported that the satellite had suffered from a control system malfunction but was then fully restored. | What is the name of the fourth BeiDou-1 satellite? | {
"answer_start": [
36
],
"text": [
"BeiDou-1D"
]
} | 0.004176 |
56e0fdc8231d4119001ac558 | BeiDou_Navigation_Satellite_System | The first satellite, BeiDou-1A, was launched on 30 October 2000, followed by BeiDou-1B on 20 December 2000. The third satellite, BeiDou-1C (a backup satellite), was put into orbit on 25 May 2003. The successful launch of BeiDou-1C also meant the establishment of the BeiDou-1 navigation system. | What was the name of the first satellite launched for the system? | {
"answer_start": [
19
],
"text": [
"BeiDou-1A"
]
} | 0.005224 |
56e1207fcd28a01900c6761f | BeiDou_Navigation_Satellite_System | On July 25, 2015, the 18th and 19th satellites were successfully launched from the Xichang Satellite Launch Center, marking the first time for China to launch two satellites at once on top of a Long March 3B/Expedition-1 carrier rocket. The Expedition-1 is an independent upper stage capable of delivering one or more spacecraft into different orbits. | When were the 18th and 19th satellites for the BeiDou system launched? | {
"answer_start": [
19
],
"text": [
"July 25, 2015"
]
} | 0.005249 |
56e0fb457aa994140058e864 | BeiDou_Navigation_Satellite_System | According to China daily. Fifteen years after the satellite system was launched, it is now generating $31.5 billion for major companies such as China Aerospace Science and Industry Corp, AutoNavi Holdings Ltd, and China North Industries Group Corp. | How much revenue for companies is generated by the BDS system? | {
"answer_start": [
33
],
"text": [
"$31.5 billion"
]
} | 0.005633 |
56e10514e3433e1400422ad7 | BeiDou_Navigation_Satellite_System | In September 2003, China intended to join the European Galileo positioning system project and was to invest €230 million (USD296 million, GBP160 million) in Galileo over the next few years. At the time, it was believed that China's "BeiDou" navigation system would then only be used by its armed forces. In October 2004, China officially joined the Galileo project by signing the Agreement on the Cooperation in the Galileo Program between the "Galileo Joint Undertaking" (GJU) and the "National Remote Sensing Centre of China" (NRSCC). Based on the Sino-European Cooperation Agreement on Galileo program, China Galileo Industries (CGI), the prime contractor of the China’s involvement in Galileo programs, was founded in December 2004. By April 2006, eleven cooperation projects within the Galileo framework had been signed between China and EU. However, the Hong Kong-based South China Morning Post reported in January 2008 that China was unsatisfied with its role in the Galileo project and was to compete with Galileo in the Asian market. | When was China Galileo Industries (CGI) founded? | {
"answer_start": [
172
],
"text": [
"December 2004"
]
} | 0.005799 |
56e10745cd28a01900c67460 | BeiDou_Navigation_Satellite_System | The first satellite, BeiDou-1A, was launched on October 31, 2000. The second satellite, BeiDou-1B, was successfully launched on December 21, 2000. The last operational satellite of the constellation, BeiDou-1C, was launched on May 25, 2003. | What was the first satellite for the BeiDou-1 system called? | {
"answer_start": [
22
],
"text": [
"BeiDou-1A"
]
} | 0.006474 |
56e0f2db231d4119001ac4c1 | BeiDou_Navigation_Satellite_System | In-mid 2015, China started the build-up of the third generation BeiDou system (BDS-3) in the global coverage constellation. The first BDS-3 satellite was launched 30 September 2015. As of March 2016, 4 BDS-3 in-orbit validation satellites have been launched. | What is the third BeiDou system called? | {
"answer_start": [
34
],
"text": [
"BDS-3"
]
} | 0.006494 |
56e0ebae7aa994140058e7cc | BeiDou_Navigation_Satellite_System | The BeiDou Navigation Satellite System (BDS, simplified Chinese: 北斗卫星导航系统; traditional Chinese: 北斗衛星導航系統; pinyin: Běidǒu wèixīng dǎoháng xìtǒng) is a Chinese satellite navigation system. It consists of two separate satellite constellations – a limited test system that has been operating since 2000, and a full-scale global navigation system that is currently under construction. | How many satellite constellations does the BeiDou Navigation Satellite System have? | {
"answer_start": [
87
],
"text": [
"two"
]
} | 0.008362 |
56e10745cd28a01900c67463 | BeiDou_Navigation_Satellite_System | The first satellite, BeiDou-1A, was launched on October 31, 2000. The second satellite, BeiDou-1B, was successfully launched on December 21, 2000. The last operational satellite of the constellation, BeiDou-1C, was launched on May 25, 2003. | When was the last satellite for the BeiDou-1 system launched? | {
"answer_start": [
77
],
"text": [
"May 25, 2003"
]
} | 0.009784 |
56e106b3e3433e1400422af4 | BeiDou_Navigation_Satellite_System | Unlike the American GPS, Russian GLONASS, and European Galileo systems, which use medium Earth orbit satellites, BeiDou-1 uses satellites in geostationary orbit. This means that the system does not require a large constellation of satellites, but it also limits the coverage to areas on Earth where the satellites are visible. The area that can be serviced is from longitude 70°E to 140°E and from latitude 5°N to 55°N. A frequency of the system is 2491.75 MHz. | What is the frequency of the BeiDou-1 system? | {
"answer_start": [
119
],
"text": [
"2491.75 MHz"
]
} | 0.01009 |
56e0fdc8231d4119001ac559 | BeiDou_Navigation_Satellite_System | The first satellite, BeiDou-1A, was launched on 30 October 2000, followed by BeiDou-1B on 20 December 2000. The third satellite, BeiDou-1C (a backup satellite), was put into orbit on 25 May 2003. The successful launch of BeiDou-1C also meant the establishment of the BeiDou-1 navigation system. | When was BeiDou-1A launched? | {
"answer_start": [
26
],
"text": [
"30 October 2000"
]
} | 0.011001 |
56e11d89e3433e1400422c23 | BeiDou_Navigation_Satellite_System | In December 2011, Xinhua stated that "[t]he basic structure of the Beidou system has now been established, and engineers are now conducting comprehensive system test and evaluation. The system will provide test-run services of positioning, navigation and time for China and the neighboring areas before the end of this year, according to the authorities." The system became operational in the China region that same month. The global navigation system should be finished by 2020. As of December 2012, 16 satellites for BeiDou-2 have been launched, 14 of them are in service. | Of the 16 satellites launched for the BeiDou-2 system, how many are operational? | {
"answer_start": [
133
],
"text": [
"14"
]
} | 0.011507 |
56e10245e3433e1400422a97 | BeiDou_Navigation_Satellite_System | On 2 November 2006, China announced that from 2008 BeiDou would offer an open service with an accuracy of 10 meters, timing of 0.2 microseconds, and speed of 0.2 meters/second.[citation needed] | What was the accuracy range that China promised to offer in 2008 with the BeiDou system? | {
"answer_start": [
45
],
"text": [
"10 meters"
]
} | 0.011652 |
56e11c2bcd28a01900c675e1 | BeiDou_Navigation_Satellite_System | The BeiDou-2 system began offering services for the Asia-Pacific region in December 2012. At this time, the system could provide positioning data between longitude 55°E to 180°E and from latitude 55°S to 55°N. | When did the BeiDou-2 system start offering services? | {
"answer_start": [
34
],
"text": [
"December 2012"
]
} | 0.012142 |
56e1161ccd28a01900c67579 | BeiDou_Navigation_Satellite_System | Compass-M1 is an experimental satellite launched for signal testing and validation and for the frequency filing on 14 April 2007. The role of Compass-M1 for Compass is similar to the role of the GIOVE satellites for the Galileo system. The orbit of Compass-M1 is nearly circular, has an altitude of 21,150 km and an inclination of 55.5 degrees. | When was the Compass-M1 satellite launched? | {
"answer_start": [
35
],
"text": [
"14 April 2007"
]
} | 0.01239 |
56e10dbdcd28a01900c674e4 | BeiDou_Navigation_Satellite_System | The ranging signals are based on the CDMA principle and have complex structure typical of Galileo or modernized GPS. Similar to the other GNSS, there will be two levels of positioning service: open and restricted (military). The public service shall be available globally to general users. When all the currently planned GNSS systems are deployed, the users will benefit from the use of a total constellation of 75+ satellites, which will significantly improve all the aspects of positioning, especially availability of the signals in so-called urban canyons. The general designer of the COMPASS navigation system is Sun Jiadong, who is also the general designer of its predecessor, the original BeiDou navigation system. | Who designed the COMPASS navigation system? | {
"answer_start": [
132
],
"text": [
"Sun Jiadong"
]
} | 0.013356 |
56e103f6e3433e1400422ab3 | BeiDou_Navigation_Satellite_System | In April 2007, the first satellite of BeiDou-2, namely Compass-M1 (to validate frequencies for the BeiDou-2 constellation) was successfully put into its working orbit. The second BeiDou-2 constellation satellite Compass-G2 was launched on 15 April 2009. On 15 January 2010, the official website of the BeiDou Navigation Satellite System went online, and the system's third satellite (Compass-G1) was carried into its orbit by a Long March 3C rocket on 17 January 2010. On 2 June 2010, the fourth satellite was launched successfully into orbit. The fifth orbiter was launched into space from Xichang Satellite Launch Center by an LM-3I carrier rocket on 1 August 2010. Three months later, on 1 November 2010, the sixth satellite was sent into orbit by LM-3C. Another satellite, the Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit) satellite, was launched from the Xichang Satellite Launch Center by a Long March-3A on 1 December 2011 (UTC). | When was the second satellite for the BeiDou-2 system launched? | {
"answer_start": [
81
],
"text": [
"15 April 2009"
]
} | 0.013405 |
56e0fd33231d4119001ac54c | BeiDou_Navigation_Satellite_System | The original idea of a Chinese satellite navigation system was conceived by Chen Fangyun and his colleagues in the 1980s. According to the China National Space Administration, the development of the system would be carried out in three steps: | Who first came up with the idea for a Chinese satellite navigation system? | {
"answer_start": [
28
],
"text": [
"Chen Fangyun"
]
} | 0.014927 |
56e10ed0cd28a01900c674f9 | BeiDou_Navigation_Satellite_System | There are two levels of service provided — a free service to civilians and licensed service to the Chinese government and military. The free civilian service has a 10-meter location-tracking accuracy, synchronizes clocks with an accuracy of 10 nanoseconds, and measures speeds to within 0.2 m/s. The restricted military service has a location accuracy of 10 centimetres, can be used for communication, and will supply information about the system status to the user. To date, the military service has been granted only to the People's Liberation Army and to the Military of Pakistan. | What is something the licensed military service can be used for? | {
"answer_start": [
95
],
"text": [
"communication"
]
} | 0.015115 |
56e11911e3433e1400422bd5 | BeiDou_Navigation_Satellite_System | Compass-M1 transmits in 3 bands: E2, E5B, and E6. In each frequency band two coherent sub-signals have been detected with a phase shift of 90 degrees (in quadrature). These signal components are further referred to as "I" and "Q". The "I" components have shorter codes and are likely to be intended for the open service. The "Q" components have much longer codes, are more interference resistive, and are probably intended for the restricted service. IQ modulation has been the method in both wired and wireless digital modulation since morsetting carrier signal 100 years ago. | What is the phase shift of the sub-signals detected in each frequency band used by Compass-M1? | {
"answer_start": [
64
],
"text": [
"90 degrees"
]
} | 0.016753 |
56e11d89e3433e1400422c22 | BeiDou_Navigation_Satellite_System | In December 2011, Xinhua stated that "[t]he basic structure of the Beidou system has now been established, and engineers are now conducting comprehensive system test and evaluation. The system will provide test-run services of positioning, navigation and time for China and the neighboring areas before the end of this year, according to the authorities." The system became operational in the China region that same month. The global navigation system should be finished by 2020. As of December 2012, 16 satellites for BeiDou-2 have been launched, 14 of them are in service. | As of December 2012, how many satellites had been launched for the BeiDou-2 system? | {
"answer_start": [
121
],
"text": [
"16"
]
} | 0.01711 |
56e1030ae3433e1400422a9c | BeiDou_Navigation_Satellite_System | In February 2007, the fourth and last satellite of the BeiDou-1 system, BeiDou-1D (sometimes called BeiDou-2A, serving as a backup satellite), was sent up into space. It was reported that the satellite had suffered from a control system malfunction but was then fully restored. | When was the fourth satellite for the BeiDou-1 system launched? | {
"answer_start": [
19
],
"text": [
"February 2007"
]
} | 0.020163 |
56e11bbce3433e1400422c0e | BeiDou_Navigation_Satellite_System | In December 2011, the system went into operation on a trial basis. It has started providing navigation, positioning and timing data to China and the neighbouring area for free from 27 December. During this trial run, Compass will offer positioning accuracy to within 25 meters, but the precision will improve as more satellites are launched. Upon the system's official launch, it pledged to offer general users positioning information accurate to the nearest 10 m, measure speeds within 0.2 m per second, and provide signals for clock synchronisation accurate to 0.02 microseconds. | When did the Compass system begin operation on a trial bases? | {
"answer_start": [
17
],
"text": [
"December 2011"
]
} | 0.020242 |
56e11a26e3433e1400422be6 | BeiDou_Navigation_Satellite_System | The investigation of the transmitted signals started immediately after the launch of Compass -M1 on 14 April 2007. Soon after in June 2007, engineers at CNES reported the spectrum and structure of the signals. A month later, researchers from Stanford University reported the complete decoding of the “I” signals components. The knowledge of the codes allowed a group of engineers at Septentrio to build the COMPASS receiver and report tracking and multipath characteristics of the “I” signals on E2 and E5B. | When did the investigation of the signals transmitted by Compass -M1 begin? | {
"answer_start": [
36
],
"text": [
"14 April 2007"
]
} | 0.020753 |
56e11e2fcd28a01900c675fd | BeiDou_Navigation_Satellite_System | The first satellite of the second-generation system, Compass-M1 was launched in 2007. It was followed by further nine satellites during 2009-2011, achieving functional regional coverage. A total of 16 satellites were launched during this phase. | What was achieved by launching 9 additional satellites from 2009-2011? | {
"answer_start": [
48
],
"text": [
"functional regional coverage"
]
} | 0.020768 |
56e10745cd28a01900c67461 | BeiDou_Navigation_Satellite_System | The first satellite, BeiDou-1A, was launched on October 31, 2000. The second satellite, BeiDou-1B, was successfully launched on December 21, 2000. The last operational satellite of the constellation, BeiDou-1C, was launched on May 25, 2003. | When was the second satellite for the BeiDou-1 system launched? | {
"answer_start": [
53
],
"text": [
"December 21, 2000"
]
} | 0.020782 |
56e10ac2cd28a01900c674bc | BeiDou_Navigation_Satellite_System | BeiDou-2 (formerly known as COMPASS) is not an extension to the older BeiDou-1, but rather supersedes it outright. The new system will be a constellation of 35 satellites, which include 5 geostationary orbit satellites for backward compatibility with BeiDou-1, and 30 non-geostationary satellites (27 in medium Earth orbit and 3 in inclined geosynchronous orbit), that will offer complete coverage of the globe. | How many non-geostationary orbit satellites will the BeiDou-2 system have? | {
"answer_start": [
94
],
"text": [
"30"
]
} | 0.020816 |
56e0fca4231d4119001ac53f | BeiDou_Navigation_Satellite_System | The official English name of the system is BeiDou Navigation Satellite System. It is named after the Big Dipper constellation, which is known in Chinese as Běidǒu. The name literally means "Northern Dipper", the name given by ancient Chinese astronomers to the seven brightest stars of the Ursa Major constellation. Historically, this set of stars was used in navigation to locate the North Star Polaris. As such, the name BeiDou also serves as a metaphor for the purpose of the satellite navigation system. | What is the Big Dipper constellation known as in Chinese? | {
"answer_start": [
46
],
"text": [
"Běidǒu"
]
} | 0.020978 |
56e10245e3433e1400422a96 | BeiDou_Navigation_Satellite_System | On 2 November 2006, China announced that from 2008 BeiDou would offer an open service with an accuracy of 10 meters, timing of 0.2 microseconds, and speed of 0.2 meters/second.[citation needed] | When did China announce service plans for the BeiDou system? | {
"answer_start": [
17
],
"text": [
"2 November 2006"
]
} | 0.021304 |
56e11f7bcd28a01900c6760d | BeiDou_Navigation_Satellite_System | In 2015, the system began its transition towards global coverage with the first launch of a new-generation of satellites, and the 17th one within the new system. | When did the BeiDou system begin transitioning to global coverage? | {
"answer_start": [
18
],
"text": [
"2015"
]
} | 0.022746 |
56e103f6e3433e1400422ab4 | BeiDou_Navigation_Satellite_System | In April 2007, the first satellite of BeiDou-2, namely Compass-M1 (to validate frequencies for the BeiDou-2 constellation) was successfully put into its working orbit. The second BeiDou-2 constellation satellite Compass-G2 was launched on 15 April 2009. On 15 January 2010, the official website of the BeiDou Navigation Satellite System went online, and the system's third satellite (Compass-G1) was carried into its orbit by a Long March 3C rocket on 17 January 2010. On 2 June 2010, the fourth satellite was launched successfully into orbit. The fifth orbiter was launched into space from Xichang Satellite Launch Center by an LM-3I carrier rocket on 1 August 2010. Three months later, on 1 November 2010, the sixth satellite was sent into orbit by LM-3C. Another satellite, the Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit) satellite, was launched from the Xichang Satellite Launch Center by a Long March-3A on 1 December 2011 (UTC). | When was the third satellite for the BeiDou-2 system launched? | {
"answer_start": [
133
],
"text": [
"17 January 2010"
]
} | 0.025779 |
56e11bbce3433e1400422c0f | BeiDou_Navigation_Satellite_System | In December 2011, the system went into operation on a trial basis. It has started providing navigation, positioning and timing data to China and the neighbouring area for free from 27 December. During this trial run, Compass will offer positioning accuracy to within 25 meters, but the precision will improve as more satellites are launched. Upon the system's official launch, it pledged to offer general users positioning information accurate to the nearest 10 m, measure speeds within 0.2 m per second, and provide signals for clock synchronisation accurate to 0.02 microseconds. | When did the Compass system begin offering navigation, positioning and timing data to China and nearby locations? | {
"answer_start": [
56
],
"text": [
"27 December"
]
} | 0.026745 |
56e10745cd28a01900c67462 | BeiDou_Navigation_Satellite_System | The first satellite, BeiDou-1A, was launched on October 31, 2000. The second satellite, BeiDou-1B, was successfully launched on December 21, 2000. The last operational satellite of the constellation, BeiDou-1C, was launched on May 25, 2003. | What was the second satellite for the BeiDou-1 system called? | {
"answer_start": [
41
],
"text": [
"BeiDou-1B"
]
} | 0.026887 |
56e11911e3433e1400422bd4 | BeiDou_Navigation_Satellite_System | Compass-M1 transmits in 3 bands: E2, E5B, and E6. In each frequency band two coherent sub-signals have been detected with a phase shift of 90 degrees (in quadrature). These signal components are further referred to as "I" and "Q". The "I" components have shorter codes and are likely to be intended for the open service. The "Q" components have much longer codes, are more interference resistive, and are probably intended for the restricted service. IQ modulation has been the method in both wired and wireless digital modulation since morsetting carrier signal 100 years ago. | What frequency bands does Compass-M1 transmit in? | {
"answer_start": [
25
],
"text": [
"E2, E5B, and E6"
]
} | 0.027057 |
56e11d89e3433e1400422c21 | BeiDou_Navigation_Satellite_System | In December 2011, Xinhua stated that "[t]he basic structure of the Beidou system has now been established, and engineers are now conducting comprehensive system test and evaluation. The system will provide test-run services of positioning, navigation and time for China and the neighboring areas before the end of this year, according to the authorities." The system became operational in the China region that same month. The global navigation system should be finished by 2020. As of December 2012, 16 satellites for BeiDou-2 have been launched, 14 of them are in service. | When is it projected that the global navigation system will be finished? | {
"answer_start": [
106
],
"text": [
"2020"
]
} | 0.028527 |
56e1161ccd28a01900c6757d | BeiDou_Navigation_Satellite_System | Compass-M1 is an experimental satellite launched for signal testing and validation and for the frequency filing on 14 April 2007. The role of Compass-M1 for Compass is similar to the role of the GIOVE satellites for the Galileo system. The orbit of Compass-M1 is nearly circular, has an altitude of 21,150 km and an inclination of 55.5 degrees. | What is the inclination of the Compass-M1 satellite? | {
"answer_start": [
93
],
"text": [
"55.5 degrees"
]
} | 0.029242 |
56e0f1b0231d4119001ac48c | BeiDou_Navigation_Satellite_System | The second generation of the system, officially called the BeiDou Navigation Satellite System (BDS) and also known as COMPASS or BeiDou-2, will be a global satellite navigation system consisting of 35 satellites, and is under construction as of January 2015[update]. It became operational in China in December 2011, with 10 satellites in use, and began offering services to customers in the Asia-Pacific region in December 2012. It is planned to begin serving global customers upon its completion in 2020. | How many satellites will the BeiDou-2 have? | {
"answer_start": [
61
],
"text": [
"35"
]
} | 0.029256 |
56e10ac2cd28a01900c674bb | BeiDou_Navigation_Satellite_System | BeiDou-2 (formerly known as COMPASS) is not an extension to the older BeiDou-1, but rather supersedes it outright. The new system will be a constellation of 35 satellites, which include 5 geostationary orbit satellites for backward compatibility with BeiDou-1, and 30 non-geostationary satellites (27 in medium Earth orbit and 3 in inclined geosynchronous orbit), that will offer complete coverage of the globe. | How many geostationary orbit satellites will the BeiDou-2 system have? | {
"answer_start": [
72
],
"text": [
"5"
]
} | 0.029747 |
56e0f1b0231d4119001ac48d | BeiDou_Navigation_Satellite_System | The second generation of the system, officially called the BeiDou Navigation Satellite System (BDS) and also known as COMPASS or BeiDou-2, will be a global satellite navigation system consisting of 35 satellites, and is under construction as of January 2015[update]. It became operational in China in December 2011, with 10 satellites in use, and began offering services to customers in the Asia-Pacific region in December 2012. It is planned to begin serving global customers upon its completion in 2020. | When did the BeiDou-2 begin construction? | {
"answer_start": [
69
],
"text": [
"January 2015"
]
} | 0.031698 |
56e10745cd28a01900c6745f | BeiDou_Navigation_Satellite_System | The first satellite, BeiDou-1A, was launched on October 31, 2000. The second satellite, BeiDou-1B, was successfully launched on December 21, 2000. The last operational satellite of the constellation, BeiDou-1C, was launched on May 25, 2003. | When was the first satellite for the BeiDou-1 system launched? | {
"answer_start": [
32
],
"text": [
"October 31, 2000"
]
} | 0.0317 |
56e0fdc8231d4119001ac55c | BeiDou_Navigation_Satellite_System | The first satellite, BeiDou-1A, was launched on 30 October 2000, followed by BeiDou-1B on 20 December 2000. The third satellite, BeiDou-1C (a backup satellite), was put into orbit on 25 May 2003. The successful launch of BeiDou-1C also meant the establishment of the BeiDou-1 navigation system. | When was the BeiDou-1C satellite launched? | {
"answer_start": [
29
],
"text": [
"30 October 2000"
]
} | 0.033508 |
56e103f6e3433e1400422ab0 | BeiDou_Navigation_Satellite_System | In April 2007, the first satellite of BeiDou-2, namely Compass-M1 (to validate frequencies for the BeiDou-2 constellation) was successfully put into its working orbit. The second BeiDou-2 constellation satellite Compass-G2 was launched on 15 April 2009. On 15 January 2010, the official website of the BeiDou Navigation Satellite System went online, and the system's third satellite (Compass-G1) was carried into its orbit by a Long March 3C rocket on 17 January 2010. On 2 June 2010, the fourth satellite was launched successfully into orbit. The fifth orbiter was launched into space from Xichang Satellite Launch Center by an LM-3I carrier rocket on 1 August 2010. Three months later, on 1 November 2010, the sixth satellite was sent into orbit by LM-3C. Another satellite, the Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit) satellite, was launched from the Xichang Satellite Launch Center by a Long March-3A on 1 December 2011 (UTC). | When was the first satellite for the BeiDou-2 system launched? | {
"answer_start": [
19
],
"text": [
"April 2007"
]
} | 0.033644 |
56e11a26e3433e1400422be9 | BeiDou_Navigation_Satellite_System | The investigation of the transmitted signals started immediately after the launch of Compass -M1 on 14 April 2007. Soon after in June 2007, engineers at CNES reported the spectrum and structure of the signals. A month later, researchers from Stanford University reported the complete decoding of the “I” signals components. The knowledge of the codes allowed a group of engineers at Septentrio to build the COMPASS receiver and report tracking and multipath characteristics of the “I” signals on E2 and E5B. | Who built the COMPASS receiver? | {
"answer_start": [
86
],
"text": [
"Septentrio"
]
} | 0.034231 |
56e1207fcd28a01900c67620 | BeiDou_Navigation_Satellite_System | On July 25, 2015, the 18th and 19th satellites were successfully launched from the Xichang Satellite Launch Center, marking the first time for China to launch two satellites at once on top of a Long March 3B/Expedition-1 carrier rocket. The Expedition-1 is an independent upper stage capable of delivering one or more spacecraft into different orbits. | Where were the 18th and 19th satellites for the BeiDou system launched from? | {
"answer_start": [
35
],
"text": [
"Xichang Satellite Launch Center"
]
} | 0.034525 |
56e0f2db231d4119001ac4c2 | BeiDou_Navigation_Satellite_System | In-mid 2015, China started the build-up of the third generation BeiDou system (BDS-3) in the global coverage constellation. The first BDS-3 satellite was launched 30 September 2015. As of March 2016, 4 BDS-3 in-orbit validation satellites have been launched. | When was the first BDS-3 satellite launched? | {
"answer_start": [
54
],
"text": [
"30 September 2015"
]
} | 0.036922 |
56e10514e3433e1400422ad6 | BeiDou_Navigation_Satellite_System | In September 2003, China intended to join the European Galileo positioning system project and was to invest €230 million (USD296 million, GBP160 million) in Galileo over the next few years. At the time, it was believed that China's "BeiDou" navigation system would then only be used by its armed forces. In October 2004, China officially joined the Galileo project by signing the Agreement on the Cooperation in the Galileo Program between the "Galileo Joint Undertaking" (GJU) and the "National Remote Sensing Centre of China" (NRSCC). Based on the Sino-European Cooperation Agreement on Galileo program, China Galileo Industries (CGI), the prime contractor of the China’s involvement in Galileo programs, was founded in December 2004. By April 2006, eleven cooperation projects within the Galileo framework had been signed between China and EU. However, the Hong Kong-based South China Morning Post reported in January 2008 that China was unsatisfied with its role in the Galileo project and was to compete with Galileo in the Asian market. | When did China join the Galileo project? | {
"answer_start": [
82
],
"text": [
"October 2004"
]
} | 0.037685 |
56e0f2db231d4119001ac4c3 | BeiDou_Navigation_Satellite_System | In-mid 2015, China started the build-up of the third generation BeiDou system (BDS-3) in the global coverage constellation. The first BDS-3 satellite was launched 30 September 2015. As of March 2016, 4 BDS-3 in-orbit validation satellites have been launched. | How many BDS-3 satellites have been launched? | {
"answer_start": [
63
],
"text": [
"4"
]
} | 0.040335 |
56e11e2fcd28a01900c675fc | BeiDou_Navigation_Satellite_System | The first satellite of the second-generation system, Compass-M1 was launched in 2007. It was followed by further nine satellites during 2009-2011, achieving functional regional coverage. A total of 16 satellites were launched during this phase. | How many satellites were launched from 2009-2011? | {
"answer_start": [
37
],
"text": [
"nine"
]
} | 0.049549 |
56e12219e3433e1400422c58 | BeiDou_Navigation_Satellite_System | The three latest satellites will jointly undergo testing of a new system of navigation signaling and inter-satellite links, and start providing navigation services when ready. | What will the three latest satellites provide after testing? | {
"answer_start": [
36
],
"text": [
"navigation services"
]
} | 0.050199 |
56e10514e3433e1400422ad4 | BeiDou_Navigation_Satellite_System | In September 2003, China intended to join the European Galileo positioning system project and was to invest €230 million (USD296 million, GBP160 million) in Galileo over the next few years. At the time, it was believed that China's "BeiDou" navigation system would then only be used by its armed forces. In October 2004, China officially joined the Galileo project by signing the Agreement on the Cooperation in the Galileo Program between the "Galileo Joint Undertaking" (GJU) and the "National Remote Sensing Centre of China" (NRSCC). Based on the Sino-European Cooperation Agreement on Galileo program, China Galileo Industries (CGI), the prime contractor of the China’s involvement in Galileo programs, was founded in December 2004. By April 2006, eleven cooperation projects within the Galileo framework had been signed between China and EU. However, the Hong Kong-based South China Morning Post reported in January 2008 that China was unsatisfied with its role in the Galileo project and was to compete with Galileo in the Asian market. | How much was China going to invest in the European Galileo positioning system project? | {
"answer_start": [
35
],
"text": [
"€230 million"
]
} | 0.051394 |
56e10feecd28a01900c67517 | BeiDou_Navigation_Satellite_System | Frequencies for COMPASS are allocated in four bands: E1, E2, E5B, and E6 and overlap with Galileo. The fact of overlapping could be convenient from the point of view of the receiver design, but on the other hand raises the issues of inter-system interference, especially within E1 and E2 bands, which are allocated for Galileo's publicly regulated service. However, under International Telecommunication Union (ITU) policies, the first nation to start broadcasting in a specific frequency will have priority to that frequency, and any subsequent users will be required to obtain permission prior to using that frequency, and otherwise ensure that their broadcasts do not interfere with the original nation's broadcasts. It now appears that Chinese COMPASS satellites will start transmitting in the E1, E2, E5B, and E6 bands before Europe's Galileo satellites and thus have primary rights to these frequency ranges. | According to International Telecommunication Union (ITU) policies, who is given higher priority to a specific frequency band? | {
"answer_start": [
122
],
"text": [
"the first nation"
]
} | 0.051904 |
56e0f1b0231d4119001ac48a | BeiDou_Navigation_Satellite_System | The second generation of the system, officially called the BeiDou Navigation Satellite System (BDS) and also known as COMPASS or BeiDou-2, will be a global satellite navigation system consisting of 35 satellites, and is under construction as of January 2015[update]. It became operational in China in December 2011, with 10 satellites in use, and began offering services to customers in the Asia-Pacific region in December 2012. It is planned to begin serving global customers upon its completion in 2020. | What is the name of the second generation of BDS? | {
"answer_start": [
24
],
"text": [
"BeiDou Navigation Satellite System"
]
} | 0.052944 |
56e10feecd28a01900c67516 | BeiDou_Navigation_Satellite_System | Frequencies for COMPASS are allocated in four bands: E1, E2, E5B, and E6 and overlap with Galileo. The fact of overlapping could be convenient from the point of view of the receiver design, but on the other hand raises the issues of inter-system interference, especially within E1 and E2 bands, which are allocated for Galileo's publicly regulated service. However, under International Telecommunication Union (ITU) policies, the first nation to start broadcasting in a specific frequency will have priority to that frequency, and any subsequent users will be required to obtain permission prior to using that frequency, and otherwise ensure that their broadcasts do not interfere with the original nation's broadcasts. It now appears that Chinese COMPASS satellites will start transmitting in the E1, E2, E5B, and E6 bands before Europe's Galileo satellites and thus have primary rights to these frequency ranges. | Which bands are used by the Galileo system for their public service? | {
"answer_start": [
81
],
"text": [
"E1 and E2"
]
} | 0.059267 |
56e11c2bcd28a01900c675e2 | BeiDou_Navigation_Satellite_System | The BeiDou-2 system began offering services for the Asia-Pacific region in December 2012. At this time, the system could provide positioning data between longitude 55°E to 180°E and from latitude 55°S to 55°N. | Where did the BeiDou-2 system start offering services in 2012? | {
"answer_start": [
31
],
"text": [
"Asia-Pacific region"
]
} | 0.062353 |
56e11bbce3433e1400422c12 | BeiDou_Navigation_Satellite_System | In December 2011, the system went into operation on a trial basis. It has started providing navigation, positioning and timing data to China and the neighbouring area for free from 27 December. During this trial run, Compass will offer positioning accuracy to within 25 meters, but the precision will improve as more satellites are launched. Upon the system's official launch, it pledged to offer general users positioning information accurate to the nearest 10 m, measure speeds within 0.2 m per second, and provide signals for clock synchronisation accurate to 0.02 microseconds. | Upon launching, the Compass system, what was the speed promised to users? | {
"answer_start": [
109
],
"text": [
"0.2 m per second"
]
} | 0.062491 |
56e108e7cd28a01900c67488 | BeiDou_Navigation_Satellite_System | In 2007, the official Xinhua News Agency reported that the resolution of the BeiDou system was as high as 0.5 metres. With the existing user terminals it appears that the calibrated accuracy is 20m (100m, uncalibrated). | What is the calibrated accuracy of the BeiDou system? | {
"answer_start": [
63
],
"text": [
"20m"
]
} | 0.069346 |
56e108e7cd28a01900c67487 | BeiDou_Navigation_Satellite_System | In 2007, the official Xinhua News Agency reported that the resolution of the BeiDou system was as high as 0.5 metres. With the existing user terminals it appears that the calibrated accuracy is 20m (100m, uncalibrated). | In 2007, what was the reported resolution of the BeiDou system? | {
"answer_start": [
43
],
"text": [
"0.5 metres"
]
} | 0.072949 |
56e0f1b0231d4119001ac48e | BeiDou_Navigation_Satellite_System | The second generation of the system, officially called the BeiDou Navigation Satellite System (BDS) and also known as COMPASS or BeiDou-2, will be a global satellite navigation system consisting of 35 satellites, and is under construction as of January 2015[update]. It became operational in China in December 2011, with 10 satellites in use, and began offering services to customers in the Asia-Pacific region in December 2012. It is planned to begin serving global customers upon its completion in 2020. | When did the BeiDou-2 begin operating? | {
"answer_start": [
81
],
"text": [
"December 2011"
]
} | 0.074438 |
56e11e2fcd28a01900c675fe | BeiDou_Navigation_Satellite_System | The first satellite of the second-generation system, Compass-M1 was launched in 2007. It was followed by further nine satellites during 2009-2011, achieving functional regional coverage. A total of 16 satellites were launched during this phase. | How many satellites were launched since 2007? | {
"answer_start": [
50
],
"text": [
"16"
]
} | 0.077496 |
56e108e7cd28a01900c6748a | BeiDou_Navigation_Satellite_System | In 2007, the official Xinhua News Agency reported that the resolution of the BeiDou system was as high as 0.5 metres. With the existing user terminals it appears that the calibrated accuracy is 20m (100m, uncalibrated). | Who reported the resolution of the BeiDou system in 2007? | {
"answer_start": [
21
],
"text": [
"Xinhua News Agency"
]
} | 0.078545 |
56e0fd33231d4119001ac54e | BeiDou_Navigation_Satellite_System | The original idea of a Chinese satellite navigation system was conceived by Chen Fangyun and his colleagues in the 1980s. According to the China National Space Administration, the development of the system would be carried out in three steps: | The China National Space Administration said the satellite navigation system would be developed in how many steps? | {
"answer_start": [
60
],
"text": [
"three"
]
} | 0.078867 |
56e106b3e3433e1400422af0 | BeiDou_Navigation_Satellite_System | Unlike the American GPS, Russian GLONASS, and European Galileo systems, which use medium Earth orbit satellites, BeiDou-1 uses satellites in geostationary orbit. This means that the system does not require a large constellation of satellites, but it also limits the coverage to areas on Earth where the satellites are visible. The area that can be serviced is from longitude 70°E to 140°E and from latitude 5°N to 55°N. A frequency of the system is 2491.75 MHz. | What type of satellites does the American GPS system use? | {
"answer_start": [
32
],
"text": [
"medium Earth orbit satellites"
]
} | 0.080749 |
56e0ec76231d4119001ac451 | BeiDou_Navigation_Satellite_System | The first BeiDou system, officially called the BeiDou Satellite Navigation Experimental System (simplified Chinese: 北斗卫星导航试验系统; traditional Chinese: 北斗衛星導航試驗系統; pinyin: Běidǒu wèixīng dǎoháng shìyàn xìtǒng) and also known as BeiDou-1, consists of three satellites and offers limited coverage and applications. It has been offering navigation services, mainly for customers in China and neighboring regions, since 2000. | How many satellites does the BeiDou-1 have? | {
"answer_start": [
105
],
"text": [
"three"
]
} | 0.091541 |
56e11e2fcd28a01900c675fb | BeiDou_Navigation_Satellite_System | The first satellite of the second-generation system, Compass-M1 was launched in 2007. It was followed by further nine satellites during 2009-2011, achieving functional regional coverage. A total of 16 satellites were launched during this phase. | When was the Compass-M1 satellite launced? | {
"answer_start": [
33
],
"text": [
"2007"
]
} | 0.094596 |
56e105afcd28a01900c67449 | BeiDou_Navigation_Satellite_System | BeiDou-1 is an experimental regional navigation system, which consists of four satellites (three working satellites and one backup satellite). The satellites themselves were based on the Chinese DFH-3 geostationary communications satellite and had a launch weight of 1,000 kilograms (2,200 pounds) each. | What is the BeiDou-1? | {
"answer_start": [
20
],
"text": [
"experimental regional navigation system"
]
} | 0.09927 |
56e0fd33231d4119001ac54d | BeiDou_Navigation_Satellite_System | The original idea of a Chinese satellite navigation system was conceived by Chen Fangyun and his colleagues in the 1980s. According to the China National Space Administration, the development of the system would be carried out in three steps: | When did Chen Fangyun come up with the idea for a satellite navigation system? | {
"answer_start": [
38
],
"text": [
"1980s"
]
} | 0.102816 |
56e11911e3433e1400422bd6 | BeiDou_Navigation_Satellite_System | Compass-M1 transmits in 3 bands: E2, E5B, and E6. In each frequency band two coherent sub-signals have been detected with a phase shift of 90 degrees (in quadrature). These signal components are further referred to as "I" and "Q". The "I" components have shorter codes and are likely to be intended for the open service. The "Q" components have much longer codes, are more interference resistive, and are probably intended for the restricted service. IQ modulation has been the method in both wired and wireless digital modulation since morsetting carrier signal 100 years ago. | What are the two sub-signals in each frequency band referred to as? | {
"answer_start": [
74
],
"text": [
"\"I\" and \"Q\""
]
} | 0.106761 |
56e12219e3433e1400422c5a | BeiDou_Navigation_Satellite_System | The three latest satellites will jointly undergo testing of a new system of navigation signaling and inter-satellite links, and start providing navigation services when ready. | How many satellites will be used to test a new system of navigation signaling? | {
"answer_start": [
18
],
"text": [
"three"
]
} | 0.106855 |
56e10feecd28a01900c67515 | BeiDou_Navigation_Satellite_System | Frequencies for COMPASS are allocated in four bands: E1, E2, E5B, and E6 and overlap with Galileo. The fact of overlapping could be convenient from the point of view of the receiver design, but on the other hand raises the issues of inter-system interference, especially within E1 and E2 bands, which are allocated for Galileo's publicly regulated service. However, under International Telecommunication Union (ITU) policies, the first nation to start broadcasting in a specific frequency will have priority to that frequency, and any subsequent users will be required to obtain permission prior to using that frequency, and otherwise ensure that their broadcasts do not interfere with the original nation's broadcasts. It now appears that Chinese COMPASS satellites will start transmitting in the E1, E2, E5B, and E6 bands before Europe's Galileo satellites and thus have primary rights to these frequency ranges. | Which frequency bands are most likely to cause issues of inter-system interference with the Galileo system? | {
"answer_start": [
87
],
"text": [
"E1 and E2"
]
} | 0.107713 |
56e0fb457aa994140058e863 | BeiDou_Navigation_Satellite_System | According to China daily. Fifteen years after the satellite system was launched, it is now generating $31.5 billion for major companies such as China Aerospace Science and Industry Corp, AutoNavi Holdings Ltd, and China North Industries Group Corp. | How long ago was the BeiDou Satellite System first launched? | {
"answer_start": [
21
],
"text": [
"Fifteen years"
]
} | 0.107829 |
56e11a26e3433e1400422be8 | BeiDou_Navigation_Satellite_System | The investigation of the transmitted signals started immediately after the launch of Compass -M1 on 14 April 2007. Soon after in June 2007, engineers at CNES reported the spectrum and structure of the signals. A month later, researchers from Stanford University reported the complete decoding of the “I” signals components. The knowledge of the codes allowed a group of engineers at Septentrio to build the COMPASS receiver and report tracking and multipath characteristics of the “I” signals on E2 and E5B. | Who reported the complete decoding of the “I” signals components? | {
"answer_start": [
63
],
"text": [
"researchers from Stanford University"
]
} | 0.10851 |
56e0ec76231d4119001ac44e | BeiDou_Navigation_Satellite_System | The first BeiDou system, officially called the BeiDou Satellite Navigation Experimental System (simplified Chinese: 北斗卫星导航试验系统; traditional Chinese: 北斗衛星導航試驗系統; pinyin: Běidǒu wèixīng dǎoháng shìyàn xìtǒng) and also known as BeiDou-1, consists of three satellites and offers limited coverage and applications. It has been offering navigation services, mainly for customers in China and neighboring regions, since 2000. | What was the first BeiDou system called? | {
"answer_start": [
24
],
"text": [
"BeiDou Satellite Navigation Experimental System"
]
} | 0.11061 |
56e0f2db231d4119001ac4c0 | BeiDou_Navigation_Satellite_System | In-mid 2015, China started the build-up of the third generation BeiDou system (BDS-3) in the global coverage constellation. The first BDS-3 satellite was launched 30 September 2015. As of March 2016, 4 BDS-3 in-orbit validation satellites have been launched. | When did China begin constructing the third BeiDou system? | {
"answer_start": [
15
],
"text": [
"In-mid 2015"
]
} | 0.114223 |
56e0ebae7aa994140058e7ce | BeiDou_Navigation_Satellite_System | The BeiDou Navigation Satellite System (BDS, simplified Chinese: 北斗卫星导航系统; traditional Chinese: 北斗衛星導航系統; pinyin: Běidǒu wèixīng dǎoháng xìtǒng) is a Chinese satellite navigation system. It consists of two separate satellite constellations – a limited test system that has been operating since 2000, and a full-scale global navigation system that is currently under construction. | How long has the limited test system been operating? | {
"answer_start": [
95
],
"text": [
"since 2000"
]
} | 0.11424 |
56e109accd28a01900c67497 | BeiDou_Navigation_Satellite_System | In 2008, a BeiDou-1 ground terminal cost around CN¥20,000RMB (US$2,929), almost 10 times the price of a contemporary GPS terminal. The price of the terminals was explained as being due to the cost of imported microchips. At the China High-Tech Fair ELEXCON of November 2009 in Shenzhen, a BeiDou terminal priced at CN¥3,000RMB was presented. | How much did a BeiDou-1 ground terminal cost in 2008? | {
"answer_start": [
32
],
"text": [
"CN¥20,000RMB"
]
} | 0.118001 |
56e10ed0cd28a01900c674f7 | BeiDou_Navigation_Satellite_System | There are two levels of service provided — a free service to civilians and licensed service to the Chinese government and military. The free civilian service has a 10-meter location-tracking accuracy, synchronizes clocks with an accuracy of 10 nanoseconds, and measures speeds to within 0.2 m/s. The restricted military service has a location accuracy of 10 centimetres, can be used for communication, and will supply information about the system status to the user. To date, the military service has been granted only to the People's Liberation Army and to the Military of Pakistan. | What is the range of accuracy for the licensed service used by Chinese government and military? | {
"answer_start": [
48
],
"text": [
"10-meter"
]
} | 0.119077 |
56e10514e3433e1400422ad8 | BeiDou_Navigation_Satellite_System | In September 2003, China intended to join the European Galileo positioning system project and was to invest €230 million (USD296 million, GBP160 million) in Galileo over the next few years. At the time, it was believed that China's "BeiDou" navigation system would then only be used by its armed forces. In October 2004, China officially joined the Galileo project by signing the Agreement on the Cooperation in the Galileo Program between the "Galileo Joint Undertaking" (GJU) and the "National Remote Sensing Centre of China" (NRSCC). Based on the Sino-European Cooperation Agreement on Galileo program, China Galileo Industries (CGI), the prime contractor of the China’s involvement in Galileo programs, was founded in December 2004. By April 2006, eleven cooperation projects within the Galileo framework had been signed between China and EU. However, the Hong Kong-based South China Morning Post reported in January 2008 that China was unsatisfied with its role in the Galileo project and was to compete with Galileo in the Asian market. | Who said in 2008 that China was unsatisfied with its involvement in the Galileo project? | {
"answer_start": [
209
],
"text": [
"South China Morning Post"
]
} | 0.119808 |
56e0ec76231d4119001ac452 | BeiDou_Navigation_Satellite_System | The first BeiDou system, officially called the BeiDou Satellite Navigation Experimental System (simplified Chinese: 北斗卫星导航试验系统; traditional Chinese: 北斗衛星導航試驗系統; pinyin: Běidǒu wèixīng dǎoháng shìyàn xìtǒng) and also known as BeiDou-1, consists of three satellites and offers limited coverage and applications. It has been offering navigation services, mainly for customers in China and neighboring regions, since 2000. | How long has the BeiDou-1 been operating? | {
"answer_start": [
131
],
"text": [
"2000"
]
} | 0.126744 |
56e1161ccd28a01900c6757a | BeiDou_Navigation_Satellite_System | Compass-M1 is an experimental satellite launched for signal testing and validation and for the frequency filing on 14 April 2007. The role of Compass-M1 for Compass is similar to the role of the GIOVE satellites for the Galileo system. The orbit of Compass-M1 is nearly circular, has an altitude of 21,150 km and an inclination of 55.5 degrees. | What is the purpose of the Compass-M1 satellite? | {
"answer_start": [
26
],
"text": [
"signal testing and validation"
]
} | 0.127087 |
56e11d89e3433e1400422c20 | BeiDou_Navigation_Satellite_System | In December 2011, Xinhua stated that "[t]he basic structure of the Beidou system has now been established, and engineers are now conducting comprehensive system test and evaluation. The system will provide test-run services of positioning, navigation and time for China and the neighboring areas before the end of this year, according to the authorities." The system became operational in the China region that same month. The global navigation system should be finished by 2020. As of December 2012, 16 satellites for BeiDou-2 have been launched, 14 of them are in service. | When did the Beidou system begin operating in China? | {
"answer_start": [
15
],
"text": [
"December 2011"
]
} | 0.12817 |
56e10dbdcd28a01900c674e3 | BeiDou_Navigation_Satellite_System | The ranging signals are based on the CDMA principle and have complex structure typical of Galileo or modernized GPS. Similar to the other GNSS, there will be two levels of positioning service: open and restricted (military). The public service shall be available globally to general users. When all the currently planned GNSS systems are deployed, the users will benefit from the use of a total constellation of 75+ satellites, which will significantly improve all the aspects of positioning, especially availability of the signals in so-called urban canyons. The general designer of the COMPASS navigation system is Sun Jiadong, who is also the general designer of its predecessor, the original BeiDou navigation system. | Where will the public service for the BeiDou system be available? | {
"answer_start": [
69
],
"text": [
"globally"
]
} | 0.128552 |
56e10dbdcd28a01900c674e5 | BeiDou_Navigation_Satellite_System | The ranging signals are based on the CDMA principle and have complex structure typical of Galileo or modernized GPS. Similar to the other GNSS, there will be two levels of positioning service: open and restricted (military). The public service shall be available globally to general users. When all the currently planned GNSS systems are deployed, the users will benefit from the use of a total constellation of 75+ satellites, which will significantly improve all the aspects of positioning, especially availability of the signals in so-called urban canyons. The general designer of the COMPASS navigation system is Sun Jiadong, who is also the general designer of its predecessor, the original BeiDou navigation system. | How many satellites will the COMPASS navigation system use? | {
"answer_start": [
96
],
"text": [
"75+"
]
} | 0.136398 |
56e106b3e3433e1400422af1 | BeiDou_Navigation_Satellite_System | Unlike the American GPS, Russian GLONASS, and European Galileo systems, which use medium Earth orbit satellites, BeiDou-1 uses satellites in geostationary orbit. This means that the system does not require a large constellation of satellites, but it also limits the coverage to areas on Earth where the satellites are visible. The area that can be serviced is from longitude 70°E to 140°E and from latitude 5°N to 55°N. A frequency of the system is 2491.75 MHz. | What type of satellites does the BeiDou-1 system use? | {
"answer_start": [
36
],
"text": [
"medium Earth orbit satellites"
]
} | 0.141679 |
56e0ebae7aa994140058e7cd | BeiDou_Navigation_Satellite_System | The BeiDou Navigation Satellite System (BDS, simplified Chinese: 北斗卫星导航系统; traditional Chinese: 北斗衛星導航系統; pinyin: Běidǒu wèixīng dǎoháng xìtǒng) is a Chinese satellite navigation system. It consists of two separate satellite constellations – a limited test system that has been operating since 2000, and a full-scale global navigation system that is currently under construction. | What are the two satellite constellations? | {
"answer_start": [
10
],
"text": [
"The BeiDou Navigation Satellite System"
]
} | 0.142919 |
56e103f6e3433e1400422ab2 | BeiDou_Navigation_Satellite_System | In April 2007, the first satellite of BeiDou-2, namely Compass-M1 (to validate frequencies for the BeiDou-2 constellation) was successfully put into its working orbit. The second BeiDou-2 constellation satellite Compass-G2 was launched on 15 April 2009. On 15 January 2010, the official website of the BeiDou Navigation Satellite System went online, and the system's third satellite (Compass-G1) was carried into its orbit by a Long March 3C rocket on 17 January 2010. On 2 June 2010, the fourth satellite was launched successfully into orbit. The fifth orbiter was launched into space from Xichang Satellite Launch Center by an LM-3I carrier rocket on 1 August 2010. Three months later, on 1 November 2010, the sixth satellite was sent into orbit by LM-3C. Another satellite, the Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit) satellite, was launched from the Xichang Satellite Launch Center by a Long March-3A on 1 December 2011 (UTC). | What is the purpose of the Compass-M1 satellite? | {
"answer_start": [
37
],
"text": [
"to validate frequencies"
]
} | 0.143422 |
56e10feecd28a01900c67513 | BeiDou_Navigation_Satellite_System | Frequencies for COMPASS are allocated in four bands: E1, E2, E5B, and E6 and overlap with Galileo. The fact of overlapping could be convenient from the point of view of the receiver design, but on the other hand raises the issues of inter-system interference, especially within E1 and E2 bands, which are allocated for Galileo's publicly regulated service. However, under International Telecommunication Union (ITU) policies, the first nation to start broadcasting in a specific frequency will have priority to that frequency, and any subsequent users will be required to obtain permission prior to using that frequency, and otherwise ensure that their broadcasts do not interfere with the original nation's broadcasts. It now appears that Chinese COMPASS satellites will start transmitting in the E1, E2, E5B, and E6 bands before Europe's Galileo satellites and thus have primary rights to these frequency ranges. | How many frequencies does the COMPASS system use? | {
"answer_start": [
26
],
"text": [
"four"
]
} | 0.1451 |
56e11911e3433e1400422bd7 | BeiDou_Navigation_Satellite_System | Compass-M1 transmits in 3 bands: E2, E5B, and E6. In each frequency band two coherent sub-signals have been detected with a phase shift of 90 degrees (in quadrature). These signal components are further referred to as "I" and "Q". The "I" components have shorter codes and are likely to be intended for the open service. The "Q" components have much longer codes, are more interference resistive, and are probably intended for the restricted service. IQ modulation has been the method in both wired and wireless digital modulation since morsetting carrier signal 100 years ago. | What is the intended purpose of the "I" component? | {
"answer_start": [
95
],
"text": [
"open service"
]
} | 0.149862 |
56e10dbdcd28a01900c674e1 | BeiDou_Navigation_Satellite_System | The ranging signals are based on the CDMA principle and have complex structure typical of Galileo or modernized GPS. Similar to the other GNSS, there will be two levels of positioning service: open and restricted (military). The public service shall be available globally to general users. When all the currently planned GNSS systems are deployed, the users will benefit from the use of a total constellation of 75+ satellites, which will significantly improve all the aspects of positioning, especially availability of the signals in so-called urban canyons. The general designer of the COMPASS navigation system is Sun Jiadong, who is also the general designer of its predecessor, the original BeiDou navigation system. | What are the ranging signals of the BeiDou system based on? | {
"answer_start": [
24
],
"text": [
"CDMA principle"
]
} | 0.152993 |
56e11911e3433e1400422bd8 | BeiDou_Navigation_Satellite_System | Compass-M1 transmits in 3 bands: E2, E5B, and E6. In each frequency band two coherent sub-signals have been detected with a phase shift of 90 degrees (in quadrature). These signal components are further referred to as "I" and "Q". The "I" components have shorter codes and are likely to be intended for the open service. The "Q" components have much longer codes, are more interference resistive, and are probably intended for the restricted service. IQ modulation has been the method in both wired and wireless digital modulation since morsetting carrier signal 100 years ago. | What is the intended purpose of the "Q" component? | {
"answer_start": [
120
],
"text": [
"restricted service"
]
} | 0.154685 |
56e113edcd28a01900c67569 | BeiDou_Navigation_Satellite_System | Although little was officially announced by Chinese authorities about the signals of the new system, the launch of the first COMPASS satellite permitted independent researchers not only to study general characteristics of the signals, but even to build a COMPASS receiver. | How much information about the COMPASS system did Chinese authorities release? | {
"answer_start": [
18
],
"text": [
"little"
]
} | 0.156398 |
56e10ed0cd28a01900c674f6 | BeiDou_Navigation_Satellite_System | There are two levels of service provided — a free service to civilians and licensed service to the Chinese government and military. The free civilian service has a 10-meter location-tracking accuracy, synchronizes clocks with an accuracy of 10 nanoseconds, and measures speeds to within 0.2 m/s. The restricted military service has a location accuracy of 10 centimetres, can be used for communication, and will supply information about the system status to the user. To date, the military service has been granted only to the People's Liberation Army and to the Military of Pakistan. | What is the range of accuracy for the free service offered to civilians? | {
"answer_start": [
45
],
"text": [
"10-meter"
]
} | 0.156479 |
56e0f1b0231d4119001ac48b | BeiDou_Navigation_Satellite_System | The second generation of the system, officially called the BeiDou Navigation Satellite System (BDS) and also known as COMPASS or BeiDou-2, will be a global satellite navigation system consisting of 35 satellites, and is under construction as of January 2015[update]. It became operational in China in December 2011, with 10 satellites in use, and began offering services to customers in the Asia-Pacific region in December 2012. It is planned to begin serving global customers upon its completion in 2020. | What is another name for the BeiDou Navigation Satellite System? | {
"answer_start": [
41
],
"text": [
"COMPASS or BeiDou-2"
]
} | 0.157078 |
56e105afcd28a01900c6744c | BeiDou_Navigation_Satellite_System | BeiDou-1 is an experimental regional navigation system, which consists of four satellites (three working satellites and one backup satellite). The satellites themselves were based on the Chinese DFH-3 geostationary communications satellite and had a launch weight of 1,000 kilograms (2,200 pounds) each. | What were the BeiDou-1 system satellites based on? | {
"answer_start": [
51
],
"text": [
"Chinese DFH-3 geostationary communications satellite"
]
} | 0.157379 |
56e10245e3433e1400422a98 | BeiDou_Navigation_Satellite_System | On 2 November 2006, China announced that from 2008 BeiDou would offer an open service with an accuracy of 10 meters, timing of 0.2 microseconds, and speed of 0.2 meters/second.[citation needed] | What was the timing and speed that China promised to offer in 2008 with the BeiDou system? | {
"answer_start": [
51
],
"text": [
"0.2 microseconds"
]
} | 0.159288 |
56e0fb457aa994140058e865 | BeiDou_Navigation_Satellite_System | According to China daily. Fifteen years after the satellite system was launched, it is now generating $31.5 billion for major companies such as China Aerospace Science and Industry Corp, AutoNavi Holdings Ltd, and China North Industries Group Corp. | What are some companies that profit from the BDS system? | {
"answer_start": [
42
],
"text": [
"China Aerospace Science and Industry Corp, AutoNavi Holdings Ltd, and China North Industries Group Corp"
]
} | 0.166536 |
56e0fca4231d4119001ac53e | BeiDou_Navigation_Satellite_System | The official English name of the system is BeiDou Navigation Satellite System. It is named after the Big Dipper constellation, which is known in Chinese as Běidǒu. The name literally means "Northern Dipper", the name given by ancient Chinese astronomers to the seven brightest stars of the Ursa Major constellation. Historically, this set of stars was used in navigation to locate the North Star Polaris. As such, the name BeiDou also serves as a metaphor for the purpose of the satellite navigation system. | What is the BeiDou Navigation Satellite System named after? | {
"answer_start": [
36
],
"text": [
"Big Dipper"
]
} | 0.166553 |