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59-547: It was formed by the fusion of the then Indian and the then Australian plates approximately 43 million years ago. The fusion happened when the mid-ocean ridge in the Indian Ocean , which separated the two plates, ceased spreading. Australia-New Guinea ( Mainland Australia , New Guinea , and Tasmania ), the Indian subcontinent , and Zealandia ( New Caledonia , New Zealand , and Norfolk Island ) are all fragments of

118-524: A line of sight by radio from satellites. The system can be used for providing position, navigation or for tracking the position of something fitted with a receiver (satellite tracking). The signals also allow the electronic receiver to calculate the current local time to a high precision, which allows time synchronisation. These uses are collectively known as Positioning, Navigation and Timing (PNT). Satnav systems operate independently of any telephonic or internet reception, though these technologies can enhance

177-496: A constellation of 7 navigational satellites. Three of the satellites are placed in geostationary orbit (GEO) and the remaining 4 in geosynchronous orbit (GSO) to have a larger signal footprint and lower number of satellites to map the region. It is intended to provide an all-weather absolute position accuracy of better than 7.6 metres (25 ft) throughout India and within a region extending approximately 1,500 km (930 mi) around it. An Extended Service Area lies between

236-572: A portion of the basin under the Indian Ocean , including parts of South China , western Indonesia , and extending up to but not including Ladakh , Kohistan , and Balochistan in Pakistan. Until roughly 140  million years ago , the Indian plate formed part of the supercontinent , Gondwana , together with modern Africa, Australia, Antarctica, and South America. Gondwana fragmented as these continents drifted apart at different velocities;

295-450: A process which led to the opening of the Indian Ocean . In the late Cretaceous approximately 100  million years ago , and subsequent to the splitting from Gondwana of conjoined Madagascar and India , the Indian plate split from Madagascar and formed Insular India . It began moving north, at about 20 cm (7.9 in) per year, and is believed to have begun colliding with Asia as early as 55  million years ago , in

354-458: A radio pulse from a known "master" location, followed by a pulse repeated from a number of "slave" stations. The delay between the reception of the master signal and the slave signals allowed the receiver to deduce the distance to each of the slaves, providing a fix . The first satellite navigation system was Transit , a system deployed by the US military in the 1960s. Transit's operation was based on

413-466: A signal that contains orbital data (from which the position of the satellite can be calculated) and the precise time the signal was transmitted. Orbital data include a rough almanac for all satellites to aid in finding them, and a precise ephemeris for this satellite. The orbital ephemeris is transmitted in a data message that is superimposed on a code that serves as a timing reference. The satellite uses an atomic clock to maintain synchronization of all

472-484: Is a deformation zone between the Indian and Australian plates, with both earthquake and global satellite navigation system data indicating that India and Australia are not moving on the same vectors northward. In due course, some expect a well defined localized boundary to reform between the Indian and Australian plates. Studies show the Ninetyeast Ridge has active faulting along its whole length so that while

531-572: Is possible the thickness of the Indian plate degenerated further as it passed over the hotspots and magmatic extrusions associated with the Deccan and Rajmahal Traps . The massive amounts of volcanic gases released during the passage of the Indian plate over the hotspots have been theorised to have played a role in the Cretaceous–Paleogene extinction event , generally held to be due to a large asteroid impact . In 2020, however, geologists at

590-590: Is reflected in the Wallace line . The eastern part ( Australian plate ) is moving northward at the rate of 5.6 cm (2.2 in) per year while the western part ( Indian plate ) is moving only at the rate of 3.7 cm (1.5 in) per year due to the impediment of the Himalayas. In terms of the middle of India and Australia's landmasses, Australia is moving northward at 3 cm (1.2 in) per year relative to India. This differential movement has resulted in

649-607: Is the world's most utilized satellite navigation system. First launch year: 1982 The formerly Soviet , and now Russian , Glo bal'naya Na vigatsionnaya S putnikovaya S istema , (GLObal NAvigation Satellite System or GLONASS), is a space-based satellite navigation system that provides a civilian radionavigation-satellite service and is also used by the Russian Aerospace Defence Forces. GLONASS has full global coverage since 1995 and with 24 active satellites. First launch year: 2000 BeiDou started as

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708-752: Is – according to Article 1.45 of the International Telecommunication Union's (ITU) Radio Regulations (RR) – defined as « A radionavigation-satellite service in which earth stations are located on board ships .» ITU Radio Regulations (article 1) classifies radiocommunication services as: The allocation of radio frequencies is provided according to Article 5 of the ITU Radio Regulations (edition 2012). To improve harmonisation in spectrum utilisation, most service allocations are incorporated in national Tables of Frequency Allocations and Utilisations within

767-555: The 2012 Indian Ocean earthquakes , suggest that the Indo-Australian plate may have already broken up into two or three separate plates due primarily to stresses induced by the collision of the Indo-Australian plate with Eurasia along what later became the Himalayas , and that the Indian plate and Australian plate may have been separate for at least 3  million years ago . Contemporary models suggest at present there

826-629: The Cretaceous–Paleogene boundary , and that a recalibration of the time scale shows no such acceleration exists. The collision with the Eurasian plate along the boundary between India and Nepal formed the orogenic belt that created the Tibetan Plateau and the Himalaya Mountains, as sediment bunched up like earth before a plow . The Indian plate is currently moving north-east at five cm (2.0 in) per year, while

885-459: The Doppler effect : the satellites travelled on well-known paths and broadcast their signals on a well-known radio frequency . The received frequency will differ slightly from the broadcast frequency because of the movement of the satellite with respect to the receiver. By monitoring this frequency shift over a short time interval, the receiver can determine its location to one side or the other of

944-507: The Eocene epoch of the Cenozoic . However, some authors suggest the collision between India and Eurasia occurred much later, around 35  million years ago . If the collision occurred between 55 and 50 Mya, the Indian plate would have covered a distance of 3,000 to 2,000 km (1,900–1,200 mi), moving more quickly than any other known plate. In 2012, paleomagnetic data from

1003-670: The Multi-functional Satellite Augmentation System , Differential GPS , GPS-aided GEO augmented navigation (GAGAN) and inertial navigation systems . The Quasi-Zenith Satellite System (QZSS) is a four-satellite regional time transfer system and enhancement for GPS covering Japan and the Asia-Oceania regions. QZSS services were available on a trial basis as of January 12, 2018, and were started in November 2018. The first satellite

1062-596: The Pacific plate . The Pacific plate sinks below the Australian plate and forms the Kermadec Trench and the island arcs of Tonga and Kermadec . New Zealand is situated along the southeastern boundary of the plate, which with New Caledonia makes up the southern and northern ends of the ancient landmass of Zealandia , which separated from Australia 85 million years ago. The central part of Zealandia sank under

1121-640: The United States 's Global Positioning System (GPS), Russia 's Global Navigation Satellite System ( GLONASS ), China 's BeiDou Navigation Satellite System (BDS), and the European Union's Galileo . Satellite-based augmentation systems (SBAS), designed to enhance the accuracy of GNSS, include Japan's Quasi-Zenith Satellite System (QZSS), India's GAGAN and the European EGNOS , all of them based on GPS. Previous iterations of

1180-580: The University of Oxford and the Alfred Wegener Institute found that new plate-motion models displayed increased movement speeds in all mid-ocean ridges during the late Cretaceous, a result irreconcilable to current theories of plate tectonics and a refutation of the plume-push hypothesis. Pérez-Díaz concludes that the accelerated movement of the Indian plate is an illusion wrought by large errors in geomagnetic reversal timing around

1239-477: The BeiDou navigation system and the present Indian Regional Navigation Satellite System (IRNSS), operationally known as NavIC, are examples of stand-alone operating regional navigation satellite systems ( RNSS ). Satellite navigation devices determine their location ( longitude , latitude , and altitude / elevation ) to high precision (within a few centimeters to meters) using time signals transmitted along

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1298-750: The Eurasian plate is moving north at only two cm (0.79 in) per year. This is causing the Eurasian plate to deform, and the Indian plate to compress at a rate of four mm (0.16 in) per year. The westerly side of the Indian plate is a transform boundary with the Arabian plate called the Owen Fracture Zone , and a divergent boundary with the African plate called the Central Indian Ridge (CIR). The northerly side of

1357-590: The Greater Himalaya and Asia at ~50 Mya. This was followed by the "hard collision" between India and Asia occurred at ~25 Mya. Subduction of the resulting ocean basin that formed between the Greater Himalayan fragment and India explains the apparent discrepancy between the crustal shortening estimates in the Himalaya and paleomagnetic data from India and Asia. However, the proposed ocean basin

1416-410: The Greater Himalaya was used to propose two collisions to reconcile the discrepancy between the amount of crustal shortening in the Himalaya (~1,300 km or 800 mi) and the amount of convergence between India and Asia (~3,600 km or 2,200 mi). These authors propose a continental fragment of northern Gondwana rifted from India, traveled northward, and initiated the "soft collision" between

1475-648: The Hindukush mountains. The northeast side of the Australian plate forms a subduction boundary with the Eurasian plate in the Indian Ocean between the borders of Bangladesh and Burma and to the southwest of the Indonesian islands of Sumatra and Borneo . Along the northern Ninety East Ridge under the Indian Ocean there appears to be a weakness zone where the Indian and Australian plates are going different ways. The subsidence boundary through Indonesia

1534-1097: The Internet. One main use of the system is in aviation . According to specifications, horizontal position accuracy when using EGNOS-provided corrections should be better than seven metres. In practice, the horizontal position accuracy is at the metre level. Similar service is provided in North America by the Wide Area Augmentation System (WAAS), in Russia by the System for Differential Corrections and Monitoring (SDCM), and in Asia, by Japan's Multi-functional Satellite Augmentation System (MSAS) and India's GPS-aided GEO augmented navigation (GAGAN). 27 operational + 3 spares Currently: 26 in orbit 24 operational 2 inactive 6 to be launched Using multiple GNSS systems for user positioning increases

1593-453: The accuracy of positions to centimetric precision (and to millimetric precision for altimetric application and also allows monitoring very tiny seasonal changes of Earth rotation and deformations), in order to build a much more precise geodesic reference system. The two current operational low Earth orbit (LEO) satellite phone networks are able to track transceiver units with accuracy of a few kilometres using doppler shift calculations from

1652-404: The ancient supercontinent of Gondwana . As the ocean floor broke apart, these land masses fragmented from one another, and for a time these centers were thought to be dormant and fused into a single plate. However, research in the early 21st century indicates plate separation of the Indo-Australian plate may have already occurred. The eastern side of the plate is the convergent boundary with

1711-527: The compression of the former plate near its centre at Sumatra and the division into the separate Indian and Australian plates again. A third plate, known as the Capricorn plate , may also be separating off the western side of the Indian plate as part of the continued breakup of the Indo-Australian plate. There is good evidence that the Indo-Australian plate is in the process of separation into new plates. Recent studies, and evidence from seismic events such as

1770-493: The delivery of weapons to targets, greatly increasing their lethality whilst reducing inadvertent casualties from mis-directed weapons. (See Guided bomb ). Satellite navigation also allows forces to be directed and to locate themselves more easily, reducing the fog of war . Now a global navigation satellite system, such as Galileo , is used to determine users location and the location of other people or objects at any given moment. The range of application of satellite navigation in

1829-610: The four major global satellite navigation systems consisting of MEO satellites, the SISRE of the BDS-3 MEO satellites was slightly inferior to 0.4 m of Galileo, slightly superior to 0.59 m of GPS, and remarkably superior to 2.33 m of GLONASS. The SISRE of BDS-3 IGSO was 0.90 m, which was on par with the 0.92 m of QZSS IGSO. However, as the BDS-3 GEO satellites were newly launched and not completely functioning in orbit, their average SISRE

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1888-774: The future is enormous, including both the public and private sectors across numerous market segments such as science, transport, agriculture, insurance, energy, etc. The ability to supply satellite navigation signals is also the ability to deny their availability. The operator of a satellite navigation system potentially has the ability to degrade or eliminate satellite navigation services over any territory it desires. In order of first launch year: First launch year: 1978 The United States' Global Positioning System (GPS) consists of up to 32 medium Earth orbit satellites in six different orbital planes . The exact number of satellites varies as older satellites are retired and replaced. Operational since 1978 and globally available since 1994, GPS

1947-519: The future version 3.0. EGNOS consists of 40 Ranging Integrity Monitoring Stations, 2 Mission Control Centres, 6 Navigation Land Earth Stations, the EGNOS Wide Area Network (EWAN), and 3 geostationary satellites . Ground stations determine the accuracy of the satellite navigation systems data and transfer it to the geostationary satellites; users may freely obtain this data from those satellites using an EGNOS-enabled receiver, or over

2006-552: The global public. The first two generations of China's BeiDou navigation system were designed to provide regional coverage. GNSS augmentation is a method of improving a navigation system's attributes, such as accuracy, reliability, and availability, through the integration of external information into the calculation process, for example, the Wide Area Augmentation System , the European Geostationary Navigation Overlay Service ,

2065-473: The ionosphere, and this slowing varies with the receiver's angle to the satellite, because that changes the distance through the ionosphere. The basic computation thus attempts to find the shortest directed line tangent to four oblate spherical shells centred on four satellites. Satellite navigation receivers reduce errors by using combinations of signals from multiple satellites and multiple correlators, and then using techniques such as Kalman filtering to combine

2124-775: The last of which was launched in December 2021. The main modulation used in Galileo Open Service signal is the Composite Binary Offset Carrier (CBOC) modulation. The NavIC (acronym for Navigation with Indian Constellation ) is an autonomous regional satellite navigation system developed by the Indian Space Research Organisation (ISRO). The Indian government approved the project in May 2006. It consists of

2183-525: The navigation system, systems can be classified as: As many of the global GNSS systems (and augmentation systems) use similar frequencies and signals around L1, many "Multi-GNSS" receivers capable of using multiple systems have been produced. While some systems strive to interoperate with GPS as well as possible by providing the same clock, others do not. Ground-based radio navigation is decades old. The DECCA , LORAN , GEE and Omega systems used terrestrial longwave radio transmitters which broadcast

2242-440: The noisy, partial, and constantly changing data into a single estimate for position, time, and velocity. Einstein 's theory of general relativity is applied to GPS time correction, the net result is that time on a GPS satellite clock advances faster than a clock on the ground by about 38 microseconds per day. The original motivation for satellite navigation was for military applications. Satellite navigation allows precision in

2301-455: The now-decommissioned Beidou-1, an Asia-Pacific local network on the geostationary orbits. The second generation of the system BeiDou-2 became operational in China in December 2011. The BeiDou-3 system is proposed to consist of 30 MEO satellites and five geostationary satellites (IGSO). A 16-satellite regional version (covering Asia and Pacific area) was completed by December 2012. Global service

2360-466: The number of visible satellites, improves precise point positioning (PPP) and shortens the average convergence time. The signal-in-space ranging error (SISRE) in November 2019 were 1.6 cm for Galileo, 2.3 cm for GPS, 5.2 cm for GLONASS and 5.5 cm for BeiDou when using real-time corrections for satellite orbits and clocks. The average SISREs of the BDS-3 MEO, IGSO, and GEO satellites were 0.52 m, 0.90 m and 1.15 m, respectively. Compared to

2419-409: The other fragments of Gondwana 100  million years ago and began moving north, carrying Insular India with it. It was once fused with the adjacent Australian plate to form a single Indo-Australian plate ; recent studies suggest that India and Australia have been separate plates for at least 3 million years. The Indian plate includes most of modern South Asia (the Indian subcontinent ) and

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2478-574: The other plates which formerly constituted Gondwana. The mantle plume that once broke up Gondwana might also have melted the lower part of the Indian subcontinent , which allowed it to move both more quickly and farther than the other parts. The remains of this plume today form the Marion hotspot ( Prince Edward Islands ), the Kerguelen hotspot , and the Réunion hotspots . As India moved north, it

2537-588: The plate is a convergent boundary with the Eurasian plate forming the Himalaya and Hindu Kush mountains , called the Main Himalayan Thrust . Satellite navigation A satellite navigation or satnav system is a system that uses satellites to provide autonomous geopositioning . A satellite navigation system with global coverage is termed global navigation satellite system ( GNSS ). As of 2024 , four global systems are operational:

2596-460: The primary service area and a rectangle area enclosed by the 30th parallel south to the 50th parallel north and the 30th meridian east to the 130th meridian east , 1,500–6,000 km beyond borders. A goal of complete Indian control has been stated, with the space segment , ground segment and user receivers all being built in India. The constellation was in orbit as of 2018, and the system

2655-572: The purpose of radionavigation . This service may also include feeder links necessary for its operation". RNSS is regarded as a safety-of-life service and an essential part of navigation which must be protected from interferences . Aeronautical radionavigation-satellite ( ARNSS ) is – according to Article 1.47 of the International Telecommunication Union's (ITU) Radio Regulations (RR) – defined as « A radionavigation service in which earth stations are located on board aircraft .» Maritime radionavigation-satellite service ( MRNSS )

2714-605: The satellite, and several such measurements combined with a precise knowledge of the satellite's orbit can fix a particular position. Satellite orbital position errors are caused by radio-wave refraction , gravity field changes (as the Earth's gravitational field is not uniform), and other phenomena. A team, led by Harold L Jury of Pan Am Aerospace Division in Florida from 1970 to 1973, found solutions and/or corrections for many error sources. Using real-time data and recursive estimation,

2773-407: The satellite. The coordinates are sent back to the transceiver unit where they can be read using AT commands or a graphical user interface . This can also be used by the gateway to enforce restrictions on geographically bound calling plans. The International Telecommunication Union (ITU) defines a radionavigation-satellite service ( RNSS ) as "a radiodetermination-satellite service used for

2832-524: The satellites in the constellation. The receiver compares the time of broadcast encoded in the transmission of three (at sea level) or four (which allows an altitude calculation also) different satellites, measuring the time-of-flight to each satellite. Several such measurements can be made at the same time to different satellites, allowing a continual fix to be generated in real time using an adapted version of trilateration : see GNSS positioning calculation for details. Each distance measurement, regardless of

2891-457: The sea. The southern margin of the plate forms a divergent boundary with the Antarctic plate . The western side is subdivided by the Indian plate that borders the Arabian plate to the north and the African plate to the south. The northern margin of the Indian plate forms a convergent boundary with the Eurasian plate , which constitutes the active orogenic process of the Himalayas and

2950-530: The simplest explanation is that the Indian and Australian plates have already separated here, it remains possible that only the Capricorn plate has separated from them. Indian plate The Indian plate (or India plate ) is a minor tectonic plate straddling the equator in the Eastern Hemisphere . Originally a part of the ancient continent of Gondwana , the Indian plate broke away from

3009-407: The system being used, places the receiver on a spherical shell at the measured distance from the broadcaster. By taking several such measurements and then looking for a point where they meet, a fix is generated. However, in the case of fast-moving receivers, the position of the signal moves as signals are received from several satellites. In addition, the radio signals slow slightly as they pass through

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3068-461: The system of 30 MEO satellites was originally scheduled to be operational in 2010. The original year to become operational was 2014. The first experimental satellite was launched on 28 December 2005. Galileo is expected to be compatible with the modernized GPS system. The receivers will be able to combine the signals from both Galileo and GPS satellites to greatly increase the accuracy. The full Galileo constellation consists of 24 active satellites,

3127-641: The systematic and residual errors were narrowed down to accuracy sufficient for navigation. Part of an orbiting satellite's broadcast includes its precise orbital data. Originally, the US Naval Observatory (USNO) continuously observed the precise orbits of these satellites. As a satellite's orbit deviated, the USNO sent the updated information to the satellite. Subsequent broadcasts from an updated satellite would contain its most recent ephemeris . Modern systems are more direct. The satellite broadcasts

3186-556: The usefulness of the positioning information generated. Global coverage for each system is generally achieved by a satellite constellation of 18–30 medium Earth orbit (MEO) satellites spread between several orbital planes . The actual systems vary, but all use orbital inclinations of >50° and orbital periods of roughly twelve hours (at an altitude of about 20,000 kilometres or 12,000 miles). GNSS systems that provide enhanced accuracy and integrity monitoring usable for civil navigation are classified as follows: By their roles in

3245-501: Was available for public use in early 2018. NavIC provides two levels of service, the "standard positioning service", which will be open for civilian use, and a "restricted service" (an encrypted one) for authorized users (including military). There are plans to expand NavIC system by increasing constellation size from 7 to 11. India plans to make the NavIC global by adding 24 more MEO satellites. The Global NavIC will be free to use for

3304-752: Was completed by December 2018. On 23 June 2020, the BDS-3 constellation deployment is fully completed after the last satellite was successfully launched at the Xichang Satellite Launch Center . First launch year: 2011 The European Union and European Space Agency agreed in March 2002 to introduce their own alternative to GPS, called the Galileo positioning system . Galileo became operational on 15 December 2016 (global Early Operational Capability, EOC). At an estimated cost of €10 billion,

3363-712: Was launched in September 2010. An independent satellite navigation system (from GPS) with 7 satellites is planned for 2023. The European Geostationary Navigation Overlay Service (EGNOS) is a satellite-based augmentation system (SBAS) developed by the European Space Agency and EUROCONTROL on behalf of the European Commission . Currently, it supplements GPS by reporting on the reliability and accuracy of their positioning data and sending out corrections. The system will supplement Galileo in

3422-556: Was marginally worse than the 0.91 m of the QZSS GEO satellites. Doppler Orbitography and Radio-positioning Integrated by Satellite (DORIS) is a French precision navigation system. Unlike other GNSS systems, it is based on static emitting stations around the world, the receivers being on satellites, in order to precisely determine their orbital position. The system may be used also for mobile receivers on land with more limited usage and coverage. Used with traditional GNSS systems, it pushes

3481-418: Was not constrained by paleomagnetic data from the key time interval of ~120 Mya to ~60 Mya. New paleomagnetic results of this critical time interval from southern Tibet do not support this Greater Indian Ocean basin hypothesis and the associated dual collision model. In 2007, German geologists suggested the reason the Indian plate moved so quickly is that it is only half as thick (100 km or 62 mi) as

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