nc33/MultiSpan_SQUAD huggingface dataset:
Web_browser

Web browsers consist of a user interface, layout engine, rendering engine, JavaScript interpreter, UI backend, networking component and data persistence component. These components achieve different functionalities of a web browser and together provide all capabilities of a web browser.

Question: A user interface, UI backend, layout engine and other things are part of what?
Answer: Web browsers

Question: The layout engine, rendering engine, user interface and other things are components that offer different what of web browsers?
Answer: functionalities
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.

Question: What is the BeiDou Navigation Satellite System?
Answer: a Chinese satellite navigation system

Question: How many satellite constellations does the BeiDou Navigation Satellite System have?
Answer: two separate satellite constellations

Question: What are the two satellite constellations?
Answer: a limited test system that has been operating since 2000, and a full-scale global navigation system

Question: How long has the limited test system been operating?
Answer: since 2000

Question: How is the BeiDou Navigation Satellite System written in traditional Chinese?
Answer: 北斗衛星導航系統
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.

Question: What was the first BeiDou system called?
Answer: the BeiDou Satellite Navigation Experimental System

Question: Who does the BeiDou-1 operate for?
Answer: mainly for customers in China and neighboring regions

Question: What is another name for the BeiDou Satellite Navigation Experimental System?
Answer: BeiDou-1

Question: How many satellites does the BeiDou-1 have?
Answer: three

Question: How long has the BeiDou-1 been operating?
Answer: since 2000
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.

Question: What is the name of the second generation of BDS?
Answer: BeiDou Navigation Satellite System

Question: What is another name for the BeiDou Navigation Satellite System?
Answer: COMPASS or BeiDou-2

Question: How many satellites will the BeiDou-2 have?
Answer: 35

Question: When did the BeiDou-2 begin construction?
Answer: January 2015

Question: When did the BeiDou-2 begin operating?
Answer: December 2011
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.

Question: When did China begin constructing the third BeiDou system?
Answer: mid 2015

Question: What is the third BeiDou system called?
Answer: BDS-3

Question: When was the first BDS-3 satellite launched?
Answer: 30 September 2015

Question: How many BDS-3 satellites have been launched?
Answer: 4
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.

Question: How long ago was the BeiDou Satellite System first launched?
Answer: Fifteen years

Question: How much revenue for companies is generated by the BDS system?
Answer: $31.5 billion

Question: What are some companies that profit from the BDS system?
Answer: China Aerospace Science and Industry Corp, AutoNavi Holdings Ltd, and China North Industries Group Corp.
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.

Question: What is the BeiDou Navigation Satellite System named after?
Answer: the Big Dipper constellation

Question: What is the Big Dipper constellation known as in Chinese?
Answer: Běidǒu

Question: What does Běidǒu translate as?
Answer: Northern Dipper

Question: Who named the constellation Běidǒu?
Answer: ancient Chinese astronomers

Question: What was the Běidǒu constellation used for?
Answer: to locate the North Star Polaris
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.

Question: What was the name of the first satellite launched for the system?
Answer: BeiDou-1A

Question: When was BeiDou-1A launched?
Answer: 20 December 2000

Question: What was the name of the third satellite launched for the system?
Answer: BeiDou-1C

Question: What was the purpose of launching the BeiDou-1C satellite?
Answer: a backup satellite

Question: When was the BeiDou-1C satellite launched?
Answer: 25 May 2003
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]

Question: When did China announce service plans for the BeiDou system?
Answer: 2 November 2006

Question: What was the accuracy range that China promised to offer in 2008 with the BeiDou system?
Answer: 10 meters

Question: What was the timing and speed that China promised to offer in 2008 with the BeiDou system?
Answer: timing of 0.2 microseconds, and speed of 0.2 meters/second
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).

Question: When was the first satellite for the BeiDou-2 system launched?
Answer: April 2007

Question: What is the the first satellite for the BeiDou-2 system called?
Answer: Compass-M1

Question: What is the purpose of the Compass-M1 satellite?
Answer: to validate frequencies for the BeiDou-2 constellation

Question: When was the second satellite for the BeiDou-2 system launched?
Answer: 15 April 2009

Question: When was the third satellite for the BeiDou-2 system launched?
Answer: 17 January 2010
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.

Question: How much was China going to invest in the European Galileo positioning system project?
Answer: €230 million (USD296 million, GBP160 million)

Question: In 2003, what was the planned purpose of the BeiDou navigation system?
Answer: only be used by its armed forces

Question: When did China join the Galileo project?
Answer: October 2004

Question: When was China Galileo Industries (CGI) founded?
Answer: December 2004

Question: Who said in 2008 that China was unsatisfied with its involvement in the Galileo project?
Answer: the Hong Kong-based South China Morning Post
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.

Question: What is the BeiDou-1?
Answer: an experimental regional navigation system

Question: The BeiDou-1 is made up of how may satellites?
Answer: four

Question: How many satellites in the BeiDou-1 system is used for back up?
Answer: one

Question: What were the BeiDou-1 system satellites based on?
Answer: the Chinese DFH-3 geostationary communications satellite

Question: How much did each satellite for the BeiDou-1 system weigh?
Answer: 1,000 kilograms (2,200 pounds) each
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.

Question: What type of satellites does the American GPS system use?
Answer: medium Earth orbit satellites

Question: What type of satellites does the BeiDou-1 system use?
Answer: satellites in geostationary orbit

Question: What is the purpose of the BeiDou-1 system using stallites in geostationary orbit?
Answer: the system does not require a large constellation of satellites

Question: What service area is covered by the BeiDou-1 system?
Answer: from longitude 70°E to 140°E and from latitude 5°N to 55°N

Question: What is the frequency of the BeiDou-1 system?
Answer: 2491.75 MHz
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.

Question: When was the first satellite for the BeiDou-1 system launched?
Answer: October 31, 2000

Question: What was the first satellite for the BeiDou-1 system called?
Answer: BeiDou-1A

Question: When was the second satellite for the BeiDou-1 system launched?
Answer: December 21, 2000

Question: What was the second satellite for the BeiDou-1 system called?
Answer: BeiDou-1B

Question: When was the last satellite for the BeiDou-1 system launched?
Answer: May 25, 2003
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.

Question: How much did a BeiDou-1 ground terminal cost in 2008?
Answer: around CN¥20,000RMB (US$2,929)

Question: How much more did a BeiDou-1 ground terminal cost than a current GPS terminal?
Answer: almost 10 times the price

Question: Why is a BeiDou-1 ground terminal so expensive?
Answer: due to the cost of imported microchips

Question: Where was the ELEXCON fair held in 2009?
Answer: Shenzhen

Question: What was presented at the ELEXCON fair in 2009?
Answer: a BeiDou terminal priced at CN¥3,000RMB
BeiDou_Navigation_Satellite_System

According to Sun Jiadong, the chief designer of the navigation system, "Many organizations have been using our system for a while, and they like it very much."

Question: Who is the chief designer of the BeiDou navigation system?
Answer: Sun Jiadong

Question: What did Sun Jiadong have to say about the BeiDou navigation system?
Answer: "Many organizations have been using our system for a while, and they like it very much."

Question: Who is Sun Jiadong?
Answer: the chief designer of the navigation system
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.

Question: What was the BeiDou-2 system previously known as?
Answer: COMPASS

Question: How may satellites will the BeiDou-2 system have?
Answer: 35

Question: How many geostationary orbit satellites will the BeiDou-2 system have?
Answer: 5

Question: How many non-geostationary orbit satellites will the BeiDou-2 system have?
Answer: 30

Question: What is the purpose of the geostationary orbit satellites in the BeiDou-2 system?
Answer: for backward compatibility with BeiDou-1
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.

Question: What are the ranging signals of the BeiDou system based on?
Answer: the CDMA principle

Question: What positioning levels will the BeiDou system offer?
Answer: open and restricted (military)

Question: Where will the public service for the BeiDou system be available?
Answer: globally to general users

Question: Who designed the COMPASS navigation system?
Answer: Sun Jiadong

Question: How many satellites will the COMPASS navigation system use?
Answer: 75+ satellites
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.

Question: What types of services will be offered by the BeiDou system?
Answer: a free service to civilians and licensed service to the Chinese government and military

Question: What is the range of accuracy for the free service offered to civilians?
Answer: 10-meter location-tracking accuracy

Question: What is the range of accuracy for the licensed service used by Chinese government and military?
Answer: 10 centimetres

Question: As of right now, who uses the licensed military service?
Answer: the People's Liberation Army and to the Military of Pakistan

Question: What is something the licensed military service can be used for?
Answer: communication
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.

Question: How many frequencies does the COMPASS system use?
Answer: four bands

Question: What are the four bands of frequencies used by the COMPASS system called?
Answer: E1, E2, E5B, and E6

Question: Which frequency bands are most likely to cause issues of inter-system interference with the Galileo system?
Answer: E1 and E2

Question: Which bands are used by the Galileo system for their public service?
Answer: E1 and E2

Question: According to International Telecommunication Union (ITU) policies, who is given higher priority to a specific frequency band?
Answer: the first nation to start broadcasting in a specific frequency
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.

Question: How much information about the COMPASS system did Chinese authorities release?
Answer: little was officially announced

Question: What is one thing launching the first COMPASS satellite enable researchers to do?
Answer: to study general characteristics of the signals

Question: What is another thing launching the first COMPASS satellite enable researchers to do?
Answer: to build a COMPASS receiver
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.

Question: When was the Compass-M1 satellite launched?
Answer: 14 April 2007

Question: What is the purpose of the Compass-M1 satellite?
Answer: for signal testing and validation and for the frequency filing

Question: The purpose of the Compass-M1 satellite is similar to the purpose of what other satellite?
Answer: the GIOVE satellites for the Galileo system

Question: What is the altitude of the Compass-M1 satellite?
Answer: 21,150 km

Question: What is the inclination of the Compass-M1 satellite?
Answer: 55.5 degrees
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.

Question: What frequency bands does Compass-M1 transmit in?
Answer: E2, E5B, and E6

Question: What is the phase shift of the sub-signals detected in each frequency band used by  Compass-M1?
Answer: 90 degrees (in quadrature)

Question: What are the two sub-signals in each frequency band referred to as?
Answer: "I" and "Q"

Question: What is the intended purpose of the "I" component?
Answer: likely to be intended for the open service

Question: What is the intended purpose of the "Q" component?
Answer: probably intended for the restricted service
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.

Question: When did the investigation of the signals transmitted by Compass -M1 begin?
Answer: immediately after the launch of Compass -M1 on 14 April 2007

Question: What did engineers at CNES report in June 2007?
Answer: the spectrum and structure of the signals

Question: Who reported the complete decoding of the “I” signals components?
Answer: researchers from Stanford University

Question: Who built the COMPASS receiver?
Answer: a group of engineers at Septentrio

Question: What was the purpose of building the COMPASS receiver?
Answer: report tracking and multipath characteristics of the “I” signals on E2 and E5B
BeiDou_Navigation_Satellite_System

Characteristics of the "I" signals on E2 and E5B are generally similar to the civilian codes of GPS (L1-CA and L2C), but Compass signals have somewhat greater power. The notation of Compass signals used in this page follows the naming of the frequency bands and agrees with the notation used in the American literature on the subject, but the notation used by the Chinese seems to be different and is quoted in the first row of the table.

Question: What is the difference between the "I" signals on E2 and E5B and the civilian codes of GPS (L1-CA and L2C)?
Answer: Compass signals have somewhat greater power