Global Positioning System - Wikipedia, the free...
Almost 70 of you visited this article in the last week above. So, I decided to share with you the European and Russian equivalent:
first the European version:
begin quote from:
GALILEO
Galileo (satellite navigation)
|
|
| Country of origin | European Union |
|---|---|
| Operator(s) | GSA, ESA |
| Type | Civilian, commercial |
| Status | In development |
| Coverage | Global |
| Precision | 1 metre (public) 1 cm (encrypted) |
| Constellation size | |
| Total satellites | 30 |
| Satellites in orbit | 12 operational + 2 in Early Orbit Phase (May 2016) |
| First launch | 2011 |
| Orbital characteristics | |
| Regime(s) | 3x MEO planes |
| Orbital height | 23,222 km (14,429 mi) |
| Other details | |
| Cost | €5 billion |
Galileo is to provide a new global search and rescue (SAR) function as part of the MEOSAR system. Satellites will be equipped with a transponder which will relay distress signals from emergency beacons to the Rescue coordination centre, which will then initiate a rescue operation. At the same time, the system is projected to provide a signal, the Return Link Message (RLM), to the emergency beacon, informing them that their situation has been detected and help is on the way. This latter feature is new and is considered a major upgrade compared to the existing Cospas-Sarsat system, which do not provide feedback to the user.[4] Tests in February 2014 found that for Galileo's search and rescue function, operating as part of the existing International Cospas-Sarsat Programme, 77% of simulated distress locations can be pinpointed within 2 km, and 95% within 5 km.[5]
The first Galileo test satellite, the GIOVE-A, was launched 28 December 2005, while the first satellite to be part of the operational system was launched on 21 October 2011. As of May 2016 the system has 14 of 30 satellites in orbit. Galileo will start offering Early Operational Capability (EOC) from 2016, go to Initial Operational Capability (IOC) in 2017–18 and reach Full Operational Capability (FOC) in 2019.[6] The complete 30-satellite Galileo system (24 operational and 6 active spares) is expected by 2020.[7]
Contents
HistoryEdit
Headquarters of the Galileo system in Prague
Main objectivesEdit
In 1999, the different concepts of the three main contributors of ESA (Germany, France and Italy)[8] for Galileo were compared and reduced to one by a joint team of engineers from all three countries. The first stage of the Galileo programme was agreed upon officially on 26 May 2003 by the European Union and the European Space Agency. The system is intended primarily for civilian use, unlike the more military-orientated systems of the United States (GPS), Russia (GLONASS), and China (Beidou-1/2, COMPASS). The European system will only be subject to shutdown for military purposes in extreme circumstances (like armed conflict[9]). It will be available at its full precision to both civil and military users.FundingEdit
The European Commission had some difficulty funding the project's next stage, after several allegedly "per annum" sales projection graphs for the project were exposed in November 2001 as "cumulative" projections which for each year projected included all previous years of sales. The attention that was brought to this multibillion-euro growing error in sales forecasts resulted in a general awareness in the Commission and elsewhere that it was unlikely that the program would yield the return on investment that had previously been suggested to investors and decision-makers.[10][better source needed] On 17 January 2002, a spokesman for the project stated that, as a result of US pressure and economic difficulties, "Galileo is almost dead."[11]A few months later, however, the situation changed dramatically. European Union member states decided it was important to have a satellite-based positioning and timing infrastructure that the US could not easily turn off in times of political conflict.[12]
The European Union and the European Space Agency agreed in March 2002 to fund the project, pending a review in 2003 (which was completed on 26 May 2003). The starting cost for the period ending in 2005 is estimated at €1.1 billion. The required satellites (the planned number is 30) were to be launched between 2011 and 2014, with the system up and running and under civilian control from 2019. The final cost is estimated at €3 billion, including the infrastructure on Earth, constructed in 2006 and 2007. The plan was for private companies and investors to invest at least two-thirds of the cost of implementation, with the EU and ESA dividing the remaining cost. The base Open Service is to be available without charge to anyone with a Galileo-compatible receiver, with an encrypted higher-bandwidth improved-precision Commercial Service available at a cost. By early 2011 costs for the project had run 50% over initial estimates.[13]
The German Aerospace Center (DLR) contributes the largest portion of the Galileo funds, and is crucial in the development and application of the system with its facilities of the Earth Observation Center, and the Institute for Communication and Navigation in Neustrelitz.[14]
Tension with the United StatesEdit
A December 2001 letter from U.S. Deputy Secretary of Defense Paul Wolfowitz to the Ministers of the EU states as part of the US-lobbying campaign against Galileo
Since Galileo was designed to provide the highest possible precision (greater than GPS) to anyone, the US was concerned that an enemy could use Galileo signals in military strikes against the US and its allies (some weapons like missiles use GNSSs for guidance). The frequency initially chosen for Galileo would have made it impossible for the US to block the Galileo signals without also interfering with its own GPS signals. The US did not want to lose their GNSS capability with GPS while denying enemies the use of GNSS. Some US officials became especially concerned when Chinese interest in Galileo was reported.[15]
An anonymous EU official claimed that the US officials implied that they might consider shooting down Galileo satellites in the event of a major conflict in which Galileo was used in attacks against American forces.[16] The EU's stance is that Galileo is a neutral technology, available to all countries and everyone. At first, EU officials did not want to change their original plans for Galileo, but have since reached a compromise, that Galileo was to use a different frequency. This allowed the blocking or jamming of either GNSS without affecting the other (jam Galileo without affecting GPS, or jam GPS but not Galileo), giving the US a greater advantage in conflicts in which it has the electronic warfare upper hand.[17]
GPS and GalileoEdit
Comparison of geostationary, GPS, GLONASS, Galileo, Compass (MEO), International Space Station, Hubble Space Telescope and Iridium constellation orbits, with the Van Allen radiation belts and the Earth to scale.[a] The Moon's orbit is around 9 times larger than geostationary orbit.[b] (In the SVG file, hover over an orbit or its label to highlight it; click to load its article.)
On 2 May 2000, SA was disabled by the President of the United States, Bill Clinton; in late 2001 the entity managing the GPS confirmed that they did not intend to enable selective availability ever again.[18] Though Selective Availability capability still exists, on 19 September 2007 the US Department of Defense announced that newer GPS satellites would not be capable of implementing Selective Availability;[19] the wave of Block IIF satellites launched in 2009, and all subsequent GPS satellites, are stated not to support SA. As old satellites are replaced in the GPS Block IIIA program, SA will cease to be an option. The modernisation programme also contains standardised features that allow GPS III and Galileo systems to inter-operate, allowing receivers to be developed to utilise GPS and Galileo together to create an even more precise GNSS.
Cooperation with the United StatesEdit
In June 2004, in a signed agreement with the United States, the European Union agreed to switch to a modulation known as BOC(1,1) (Binary Offset Carrier 1.1) allowing the coexistence of both GPS and Galileo, and the future combined use of both systems.The European Union also agreed to address the "mutual concerns related to the protection of allied and US national security capabilities."[9]
First experimental satellites: GIOVE-A and GIOVE-BEdit
The first experimental satellite, GIOVE-A, was launched in December 2005 and was followed by a second test satellite, GIOVE-B, launched in April 2008. After successful completion of the In-Orbit Validation (IOV) phase, additional satellites were launched. On 30 November 2007 the 27 EU transportation ministers involved reached an agreement that Galileo should be operational by 2013,[20] but later press releases suggest it was delayed to 2014.[21]Funding again, governance issuesEdit
In mid-2006 the public/private partnership fell apart, and the European Commission decided to nationalise the Galileo programme.[22]In early 2007 the EU had yet to decide how to pay for the system and the project was said to be "in deep crisis" due to lack of more public funds.[23] German Transport Minister Wolfgang Tiefensee was particularly doubtful about the consortium's ability to end the infighting at a time when only one testbed satellite had been successfully launched.
Although a decision was yet to be reached, on 13 July 2007[24] EU countries discussed cutting €548m ($755m, £370m) from the union's competitiveness budget for the following year and shifting some of these funds to other parts of the financing pot, a move that could meet part of the cost of the union's Galileo satellite navigation system. European Union research and development projects could be scrapped to overcome a funding shortfall.
In November 2007, it was agreed to reallocate funds from the EU's agriculture and administration budgets[25] and to soften the tendering process in order to invite more EU companies.[26]
In April 2008, the EU transport ministers approved the Galileo Implementation Regulation. This allowed the €3.4bn to be released from the EU's agriculture and administration budgets[27] to allow the issuing of contracts to start construction of the ground station and the satellites.
In June 2009, the European Court of Auditors published a report, pointing out governance issues, substantial delays and budget overruns that led to project stalling in 2007, leading to further delays and failures.[28]
In October 2009, the European Commission cut the number of satellites definitively planned from 28 to 22, with plans to order the remaining six at a later time. It also announced that the first OS, PRS and SoL signal would be available in 2013, and the CS and SOL some time later. The €3.4 billion budget for the 2006–2013 period was considered insufficient.[29] In 2010 the think-tank Open Europe estimated the total cost of Galileo from start to 20 years after completion at €22.2 billion, borne entirely by taxpayers. Under the original estimates made in 2000, this cost would have been €7.7 billion, with €2.6 billion borne by taxpayers and the rest by private investors.[30]
In November 2009, a ground station for Galileo was inaugurated near Kourou (French Guiana).[31]
The launch of the first four in-orbit validation (IOV) satellites was planned for the second half of 2011, and the launch of full operational capability (FOC) satellites was planned to start in late 2012.
In March 2010 it was verified that the budget for Galileo would only be available to provide the 4 IOV and 14 FOC satellites by 2014, with no funds then committed to bring the constellation above this 60% capacity.[32] Paul Verhoef, the satellite navigation program manager at the European Commission, indicated that this limited funding would have serious consequences commenting at one point "To give you an idea, that would mean that for three weeks in the year you will not have satellite navigation" in reference to the proposed 18-vehicle constellation.
In July 2010, the European Commission estimated further delays and additional costs of the project to grow up to €1.5-€1.7 billion, and moved the estimated date of completion to 2018. After completion the system will need to be subsidised by governments at €750 million per year.[33] An additional €1.9 billion was planned to be spent bringing the system up to the full complement of 30 satellites (27 operational + 3 active spares).[13][34]
In December 2010, EU ministers in Brussels voted Praha (Prague), in the Czech Republic, as the headquarters of the Galileo project.[35]
In January 2011, infrastructure costs up to 2020 were estimated at €5.3 billion. In that same month, Wikileaks revealed that Berry Smutny, the CEO of the German satellite company OHB-System, said that Galileo "is a stupid idea that primarily serves French interests".[36] The BBC understood in 2011 that €500 million (£440M) would become available to make the extra purchase, taking Galileo within a few years from 18 operational satellites to 24.[37]
Galileo launch on a Soyuz rocket, 21 October 2011
22 further satellites with Full Operational Capability (FOC) were on order as of 2012. The first two launched together on a Soyuz rocket from French Guiana on 22 August 2014.[40][41][42]
International involvementEdit
In September 2003, China joined the Galileo project. China was to invest €230 million (US$302 million, GBP 155 million, CNY 2.34 billion) in the project over the following years.[43]
In July 2004, Israel signed an agreement with the EU to become a partner in the Galileo project.[44]
On 3 June 2005 the EU and Ukraine signed an agreement for Ukraine to join the project, as noted in a press release.[45]
As of November 2005, Morocco also joined the programme.
In Mid-2006, the Public-Private Partnership fell apart and the European Commission decided to nationalise Galileo as an EU programme.[22]
In November 2006, China opted instead to independently develop the Beidou navigation system satellite navigation system.[46] When Galileo was viewed as a private-sector development with public-sector financial participation, European Commission program managers sought Chinese participation in pursuit of Chinese cash in the short term and privileged access to China's market for positioning and timing applications in the longer term. However, due to security and technology-independence policy from European Commission, China was, in effect, dis-invited from Galileo and without a return of its monetary investment, a decision that was reinforced by China's move to build its own global system, called Beidou/Compass. At the Munich Satellite Navigation Summit on 10 March 2010, a Chinese government official asked the European Commission why it no longer wanted to work with China, and when China's cash investment in Galileo would be returned.[47]
On 30 November 2007, the 27 member states of the European Union unanimously agreed to move forward with the project, with plans for bases in Germany and Italy. Spain did not approve during the initial vote, but approved it later that day. This greatly improves the viability of the Galileo project: "The EU's executive had previously said that if agreement was not reached by January 2008, the long-troubled project would essentially be dead."[48]
On 3 April 2009, Norway too joined the programme pledging €68.9 million toward development costs and allowing its companies to bid for the construction contracts. Norway, while not a member of the EU, is a member of ESA.[49]
On 18 December 2013, Switzerland signed a cooperation agreement to fully participate in the program, and retroactively contributed €80 million for the period 2008-2013. As a member of ESA, it already collaborated in the development of the Galileo satellites, contributing the state-of-the-art hydrogen-maser clocks. Switzerland's financial commitment for the period 2014-2020 will be calculated in accordance with the standard formula applied for the Swiss participation in the EU research Framework Programme.[50]
In July 2004, Israel signed an agreement with the EU to become a partner in the Galileo project.[44]
On 3 June 2005 the EU and Ukraine signed an agreement for Ukraine to join the project, as noted in a press release.[45]
As of November 2005, Morocco also joined the programme.
In Mid-2006, the Public-Private Partnership fell apart and the European Commission decided to nationalise Galileo as an EU programme.[22]
In November 2006, China opted instead to independently develop the Beidou navigation system satellite navigation system.[46] When Galileo was viewed as a private-sector development with public-sector financial participation, European Commission program managers sought Chinese participation in pursuit of Chinese cash in the short term and privileged access to China's market for positioning and timing applications in the longer term. However, due to security and technology-independence policy from European Commission, China was, in effect, dis-invited from Galileo and without a return of its monetary investment, a decision that was reinforced by China's move to build its own global system, called Beidou/Compass. At the Munich Satellite Navigation Summit on 10 March 2010, a Chinese government official asked the European Commission why it no longer wanted to work with China, and when China's cash investment in Galileo would be returned.[47]
On 30 November 2007, the 27 member states of the European Union unanimously agreed to move forward with the project, with plans for bases in Germany and Italy. Spain did not approve during the initial vote, but approved it later that day. This greatly improves the viability of the Galileo project: "The EU's executive had previously said that if agreement was not reached by January 2008, the long-troubled project would essentially be dead."[48]
On 3 April 2009, Norway too joined the programme pledging €68.9 million toward development costs and allowing its companies to bid for the construction contracts. Norway, while not a member of the EU, is a member of ESA.[49]
On 18 December 2013, Switzerland signed a cooperation agreement to fully participate in the program, and retroactively contributed €80 million for the period 2008-2013. As a member of ESA, it already collaborated in the development of the Galileo satellites, contributing the state-of-the-art hydrogen-maser clocks. Switzerland's financial commitment for the period 2014-2020 will be calculated in accordance with the standard formula applied for the Swiss participation in the EU research Framework Programme.[50]
System descriptionEdit
Space segmentEdit
Constellation visibility from a location on Earth's surface (animation)
- 30 in-orbit spacecraft (24 in full service and 6 spares)
- Orbital altitude: 23,222 km (MEO)
- 3 orbital planes, 56° inclination, ascending nodes separated by 120° longitude (8 operational satellites and 2 active spares per orbital plane)
- Satellite lifetime: >12 years
- Satellite mass: 675 kg
- Satellite body dimensions: 2.7 m × 1.2 m × 1.1 m
- Span of solar arrays: 18.7 m
- Power of solar arrays: 1.5 kW (end of life)
Ground segmentEdit
The system's orbit and signal accuracy is controlled by a ground segment consisting of:- 1 ground control centre, located in Oberpfaffenhofen
- 1 ground mission centre, located in Fucino
- 5 tracking stations, located in Kiruna, Kourou, Noumea, Sainte-Marie, Réunion & Redu
- Several uplink stations
- Several sensor stations
- A data dissemination network between stations
ServicesEdit
The Galileo system will have five main services:- Open access navigation
- This will be available without charge for use by anyone with appropriate mass-market equipment; simple timing, and positioning down to 1 metre.
- Commercial navigation (encrypted)
- High precision to the centimetre; guaranteed service for which service providers will charge fees.
- Safety of life navigation
- Open service; for applications where guaranteed precision is essential. Integrity messages will warn of errors.
- Public regulated navigation (encrypted)
- Continuous availability even if other services are disabled in time of crisis; Government agencies will be main users.
- Search and rescue
- System will pick up distress beacon locations; feasible to send feedback, e.g. confirming help is on its way.
ConceptEdit
Each satellite will have two rubidium atomic clocks and two passive hydrogen maser atomic clocks, critical to any satellite-navigation system, and a number of other components. The clocks will provide an accurate timing signal to allow a receiver to calculate the time that it takes the signal to reach it. This information is used to calculate the position of the receiver by trilaterating the difference in received signals from multiple satellites.For more information of the concept of global satellite navigation systems, see GNSS and GNSS positioning calculation.
ConstellationEdit
Main article: List of Galileo satellites
| Block | Launch Period |
Satellite launches | Currently in orbit and healthy |
|||
|---|---|---|---|---|---|---|
| Success | Failure | Planned | ||||
| GIOVE | 2005–2008 | 2 | 0 | 0 | 0 | |
| IOV | 2011–2012 | 4 | 0 | 0 | 3 | |
| FOC | From 2014 | 10 | 0* | 18 | 10 | |
| Total | 16 | 0 | 18 | 13 | ||
| * Two partial launch failures (Last update: 24 May 2016) For a more complete list, see list of Galileo satellites |
||||||
Galileo satellite test beds: GIOVEEdit
Main article: GIOVE
GIOVE-A was successfully launched 28 December 2005
- GIOVE-A is the first GIOVE (Galileo In-Orbit Validation Element) test satellite. It was built by Surrey Satellite Technology Ltd (SSTL), and successfully launched on 28 December 2005 by the European Space Agency and the Galileo Joint. Operation of GIOVE-A ensured that Galileo meets the frequency-filing allocation and reservation requirements for the International Telecommunication Union (ITU), a process that was required to be complete by June 2006.
- GIOVE-B, built by Astrium and Thales Alenia Space, has a more advanced payload than GIOVE-A. It was successfully launched on 27 April 2008 at 22:16 UTC (4.16 am Baikonur time) aboard a Soyuz-FG/Fregat rocket provided by Starsem.
The GIOVE Mission[54][55] segment operated by European Satellite Navigation Industries used the GIOVE-A/B satellites to provide experimental results based on real data to be used for risk mitigation for the IOV satellites that followed on from the testbeds. ESA organised the global network of ground stations to collect the measurements of GIOVE-A/B with the use of the GETR receivers for further systematic study. GETR receivers are supplied by Septentrio as well as the first Galileo navigation receivers to be used to test the functioning of the system at further stages of its deployment. Signal analysis of GIOVE-A/B data confirmed successful operation of all the Galileo signals with the tracking performance as expected.
In-Orbit Validation (IOV) satellitesEdit
These testbed satellites were followed by four IOV Galileo satellites that are much closer to the final Galileo satellite design. The Search & Rescue feature is also installed.[56] The first two satellites were launched on 21 October 2011 from Guiana Space Centre using a Soyuz launcher,[57] the other two on 12 October 2012.[58] This enables key validation tests, since earth-based receivers such as those in cars and phones need to "see" a minimum of four satellites in order to calculate their position in three dimensions.[58] Those 4 IOV Galileo satellites were constructed by Astrium GmbH and Thales Alenia Space. On 12 March 2013, a first fix was performed using those four IOV satellites.[59] Once this In-Orbit Validation (IOV) phase has been completed, the remaining satellites will be installed to reach the Full Operational Capability.Full Operational Capability (FOC) satellitesEdit
On 7 January 2010, it was announced that the contract to build the first 14 FOC satellites was awarded to OHB System and Surrey Satellite Technology Limited (SSTL). Fourteen satellites will be built at a cost of €566M (£510M; $811M).[60] Arianespace will launch the satellites for a cost of €397M (£358M; $569M). The European Commission also announced that the €85 million contract for system support covering industrial services required by ESA for integration and validation of the Galileo system had been awarded to Thales Alenia Space. Thales Alenia Space subcontract performances to Astrium GmbH and security to Thales Communications.In February 2012, an additional order of eight satellites was awarded to OHB Systems for €250M ($327M), after outbidding EADS Astrium tender offer. Thus bringing the total to 22 FOC satellites.[61]
On 7 May 2014, the first two FOC satellites landed in Guyana for their joint launch planned in summer[62] Originally planned for launch during 2013, problems tooling and establishing the production line for assembly led to a delay of a year in serial production of Galileo satellites. These two satellites (Galileo satellites GSAT0201 and GSAT0202) were launched on 22 August 2014.[63] The names of these satellites are Doresa and Milena named after European children who had previously won a drawing contest.[64] On 23 August 2014, launch service provider Arianespace announced that the flight VS09 experienced anomaly and satellites were injected into an incorrect orbit.[65]
Satellites GSAT0203 and GSAT0204 were launched successfully on 27 March 2015 from Guiana Space Centre using a Soyuz four stage launcher.[66][67] Using the same Soyuz launcher and launchpad, satellites GSAT0205 and GSAT0206 were launched successfully on 11 September 2015.[68]
Satellites GSAT0208 and GSAT0209 were successfully launched from Kourou, French Guiana, using the Soyuz launcher on December 17, 2015.[69][70][71][72]
Starting in 2016, deployment of the last twelve satellites will use a modified Ariane 5 launcher, named Ariane 5 ES, capable of placing four Galileo satellites into orbit per launch.[73]
Satellites GSAT0210 and GSAT0211 were launched on 24 May 2016 and are being commissioned. The next four are planned for launch in November 2016 on an Ariane 5 ES.[74]
Applications and impactEdit
Science projects using GalileoEdit
In July 2006 an international consortium of universities and research institutions embarked on a study of potential scientific applications of the Galileo constellation. This project, named GEO6,[75] is a broad study oriented to the general scientific community, aiming to define and implement new applications of Galileo.Among the various GNSS users identified by the Galileo Joint Undertaking,[76] the GEO6,[75] project addresses the Scientific User Community (UC).
The GEO6[75] project aims at fostering possible novel applications within the scientific UC of GNSS signals, and particularly of Galileo.
The AGILE[77] project is an EU-funded project devoted to the study of the technical and commercial aspects of location-based services (LBS). It includes technical analysis of the benefits brought by Galileo (and EGNOS) and studies the hybridisation of Galileo with other positioning technologies (network-based, WLAN, etc.). Within these project, some pilot prototypes were implemented and demonstrated.
On the basis of the potential number of users, potential revenues for Galileo Operating Company or Concessionaire (GOC), international relevance, and level of innovation, a set of Priority Applications (PA) will be selected by the consortium and developed within the time-frame of the same project.
These applications will help to increase and optimise the use of the EGNOS services and the opportunities offered by the Galileo Signal Test-Bed (GSTB-V2) and the Galileo (IOV) phase.
CoinsEdit
Austrian €25 European Satellite Navigation commemorative coin, back
See alsoEdit
- Binary Offset Carrier modulation – the modulation family used in Galileo
- Commercialization of space
- European Geostationary Navigation Overlay Service
- Multiplexed binary offset carrier modulation - the modulation type chosen for Galileo Open Service signals and modernized GPS signals
NotesEdit
- ^ Orbital periods and speeds are calculated using the relations 4π²R³ = T²GM and V²R = GM, where R = radius of orbit in metres, T = orbital period in seconds, V = orbital speed in m/s, G = gravitational constant ≈ 6.673×10−11 Nm²/kg², M = mass of Earth ≈ 5.98×1024 kg.
- ^ Approximately 8.6 times (in radius and length) when the moon is nearest (363 104 km ÷ 42 164 km) to 9.6 times when the moon is farthest (405 696 km ÷ 42 164 km).
ReferencesEdit
- ^ "On a Civil Global Navigation Satellite System (GNSS) between the European Community and its Member States and Ukraine" (PDF). Retrieved 12 January 2015.
- ^ "Galileo navigational system enters testing stage". Deutsche Welle. Retrieved 13 October 2012.
- ^ "Why Europe needs Galileo". ESA. 12 April 2010. Retrieved 21 June 2014.
- ^ "What is Galileo?". ESA. 11 April 2010. Retrieved 21 December 2010.
- ^ Space Daily
- ^ "Galileo’s contribution to the MEOSAR system". European Commission. Retrieved 30 December 2015.
- ^ Launch of first 2 operational Galileo IOV Satellites. Ec.europa.eu (21 October 2011). Retrieved on 29 October 2011.
- ^ [1]
- ^ a b Christine Johnson U.S., EU to Sign Landmark GPS-Galileo Agreement. dublin.usembassy.gov. U.S.-EU Summit: County Clare 25–26 June 2004
- ^ Van Der Jagt, Culver "Galileo: The Declaration of European Independence" a presentation at the Royal Institute of Navigation 7 November 2001
- ^ Ian Sample Europe and US clash on satellite system. Guardian.co.uk. 8 December 2003. Retrieved 29 October 2011.
- ^ a b Johnson, Chalmers (2008). Nemesis: The Last Days of the American Republic. Holt. p. 235. ISBN 0-8050-8728-1.
- ^ a b Taverna, Michael A. (1 February 2011). "Completing Galileo To Cost $2.5 Billion". Aviation Weekly.
- ^ German Aerospace Center DLR - Neustrelitz, Mecklenburg
- ^ "EU, U.S. split over Galileo M-code overlay". GPS World. FindArticles.com. December 2002. Retrieved 9 December 2008.
- ^ "US Could Shoot Down EU Satellites if Used by Foes in Wartime". AFP. 24 October 2004. Retrieved 9 September 2008.
- ^ Giegerich, Bastian (2005). "Satellite States – Transatlantic Conflict and the Galileo System". Paper presented at the annual meeting of the International Studies Association, Hilton Hawaiian Village, Honolulu, Hawaii, Mar 05, 2005. Unpublished Manuscript.
- ^ Selective Availability. Retrieved 31 August 2007.
- ^ "DoD Permanently Discontinues Procurement of Global Positioning System Selective Availability". DefenseLink. 18 September 2007. Retrieved 17 December 2007.
- ^ "'Unanimous backing' for Galileo". BBC. 30 November 2007. Retrieved 19 April 2010.
- ^ "Commission awards major contracts to make Galileo operational early 2014". 7 January 2010. Retrieved 19 April 2010.
- ^ a b http://www.insidegnss.com/node/1426 Inside GNSS
- ^ EU: Galileo project in deep 'crisis'. CNN. 8 May 2007
- ^ MSN.com Archived February 24, 2013, at the Wayback Machine.
- ^ EU agrees 2008 budget to include Galileo financing. EUbusiness.com – business, legal and financial news and information from the European Union. 26 November 2007
- ^ "Galileo 'compromise' is emerging". BBC News. 23 November 2007. Retrieved 3 May 2010.
- ^ "Galileo legal process ticks over". BBC News. 7 April 2008. Retrieved 3 May 2010.
- ^ European Court of Auditors – Special Report on the management of the Galileo programme's development and validation phase
- ^ Europe Cuts Galileo Sats Order. Aviation Week (26 October 2009). Retrieved 29 October 2011.
- ^ "The EU's Galileo satellite project could cost UK taxpayers £2.6 billion more than originally planned" (Press release). openeurope.org.uk. 17 October 2010. Retrieved 24 November 2010.
- ^ Inauguration of site of Galileo station at Kourou, official website of esa
- ^ Initial Galileo Validation Satellites Delayed. Spacenews.com (10 March 2010). Retrieved 29 October 2011.
- ^ "EU Expects Galileo Project Costs to Explode". Spiegel. 2011.
- ^ "Galileo's navigation control hub opens in Fucino". ESA. 20 December 2010. Retrieved 20 December 2010.
- ^ Prague To Host EU Satellite Navigation Agency – Radio Free Europe, 13 December 2010
- ^ OHB-System CEO Calls Galileo a Waste of German Tax Payer Money Date 22 October 2009. Aftenposten.no. Retrieved 29 October 2011.
- ^ "Europe's Galileo sat-nav in big cash boost". BBC News. 22 June 2011.
- ^ Arianespace website. Arianespace.com. Retrieved 29 October 2011.
- ^ Arianespace website. Arianespace.com. Retrieved 12 October 2012.
- ^ "Galileo: Europe's version of GPS reaches key phase". BBC. 12 October 2012. Retrieved 12 October 2012.
- ^ European Space Agency website (Retrieved 22 December 2013)
- ^ "Rocket blasts off with Galileo sat-nav satellites". BBC. 22 August 2014.
- ^ China joins EU's satellite network – BBC News, 19 September 2003
- ^ Israel joins Galileo. The Israel Entity MATIMOP, on the way to becoming a Member of the Galileo Joint Undertaking. eu-del.org.il. 18 May 2005
- ^ Press release. Europa.eu (3 June 2005). Retrieved 29 October 2011.
- ^ Marks, Paul. "China's satellite navigation plans threaten Galileo". NewScientist.com. Retrieved 19 November 2006.
- ^ China was dis-invited from Galileo-spacenews.com, 12 March 2010
- ^ "'Unanimous backing' for Galileo". BBC News. 30 November 2007. Retrieved 3 May 2010.
- ^ Norway joins EU's Galileo satnav project. GPSdaily.com. 3 April 2009. Retrieved 29 October 2011.
- ^ Switzerland joins the EU's Galileo satellite navigation programme europa.eu Press release, 18 December 2013. Retrieved
- ^ "Galileo fact sheet" (PDF). ESA. 15 February 2013. Retrieved 8 December 2015.
- ^ Galileo System Test Bed Version 1 experimentation is now complete, ESA News release, 7 January 2005
- ^ GIOVE-A2 to secure the Galileo programme, ESA News release, 5 March 2007
- ^ GIOVE mission core infrastructure, ESA press release, 26 February 2007.
- ^ One year of Galileo signals; new website opens, ESA press release, 12 January 2007.
- ^ Galileo IOV Satellites. (2014, November 3). Navipedia, . Retrieved 21:22, May 1, 2015 from http://navipedia.net/index.php?title=Galileo_IOV_Satellites&oldid=13446.
- ^ Soyuz carrying Galileo satellites launched. Bangkok Post (21 October 2011). Retrieved 29 October 2011.
- ^ a b "Galileo: Europe's version of GPS reaches key phase". BBC. 12 October 2012. Retrieved 12 October 2012.
- ^ Galileo fixes Europe's position in history
- ^ Amos, Jonathan (7 January 2010). "EU awards Galileo satellite-navigation contracts". BBC News.
- ^ Dunmore, Charlie (1 February 2012). "UPDATE 1-OHB beats EADS to Galileo satellite contract -sources". Reuters.
- ^ Next Galileo satellites arrive at Europe's Spaceport
- ^ http://www.bbc.com/news/science-environment-28860851
- ^ Rhian, Jason (22 August 2014). "Doresa and Milena Galileo spacecraft rise into morning sky via Soyuz ST-B". Spaceflight Insider.
- ^ "Galileo satellites experience orbital injection anomaly on Soyuz launch: Initial report" (Press release). 23 August 2014. Retrieved 27 August 2014.
- ^ "Galileo satellites well on way to working orbit". European Space Agency. 2015-04-10. Retrieved 2015-05-31.
- ^ "Arianespace continues deployment of Galileo, a flagship project for Europe" (PDF). Arianespace. March 2015. Retrieved 2015-05-31.
- ^ "Galileo taking flight: ten satellites now in orbit". European Space Agency. 2015-09-11.
- ^ "Galileo pair preparing for December launch". European Space Agency. 2 November 2015. Retrieved 13 December 2015.
- ^ "Vega light rocket makes sixth successful launch".
Launch [...] is scheduled for 17 December. Soyuz Flight VS13 will orbit two more satellites for Europe’s Galileo navigation system.
- ^ "Europe adds two more satellites to Galileo sat-nav system". Retrieved 2015-12-17.
- ^ Correspondent, Jonathan Amos BBC Science. "Two more Galileo satellites launched". BBC News. Retrieved 2015-12-17.
- ^ "Arianespace serves the Galileo constellation and Europe's ambitions in space with the signature of three new launch services using Ariane 5 ES". Arianespace. 2014-08-20.
- ^ Space Flight Now launchschedule
- ^ a b c gnss-geo6.org
- ^ galileoju.com
- ^ galileo-in-lbs.com
BibliographyEdit
- The Galileo Project – Galileo Design consolidation, European Commission, 2003
- Guenter W. Hein, Jeremie Godet, et al.: Status of Galileo Frequency and Signal Design, Proc. ION GPS 2002.
- Dee Ann Divis: Military role for Galileo emerges. GPS World, May 2002, Vol. 13, No. 5, p. 10.
- Dr Richard North: Galileo – The Military and Political Dimensions. 2004.
- Jaizki Mendizabal; Roc Berenguer; Juan Melendez (2009). GPS and Galileo. McGraw Hill. ISBN 978-0-07-159869-9.
Further readingEdit
- Psiaki, M. L., "Block Acquisition of weak GPS signals in a software receiver", Proceedings of ION GPS 2001, the 14th International Technical Meeting of the Satellite Division of the Institute of Navigation, Salt Lake City, Utah, 11–14 September 2001, pp. 2838–2850.
- Bandemer, B., Denks, H., Hornbostel, A., Konovaltsev, A., "Performance of acquisition methods for Galileo SW receivers", European Journal of Navigation, Vol.4, No. 3, pp 17–9, July 2006
- Van Der Jagt, Culver W. Galileo : The Declaration of European Independence : a dissertation (2002). CALL #JZ1254 .V36 2002, Description xxv, 850 p. : ill. ; 30 cm. + 1 CD-ROM
External linksEdit
- Official website
- Galileo ESA website
- European GNSS Supervisory Authority (GSA) – Europa
- Navipedia information on Galileo—Wiki initiated by the European Space Agency
- Galileo 11 Real Time Tracking
- Galileo 12 Real Time Tracking
GLONASS.
GLONASS
GLONASS logo
|
|
| Country of origin | Russia |
|---|---|
| Operator(s) | VKO |
| Type | Military |
| Status | Operational |
| Coverage | Global |
| Precision | 5–10 meters |
| Constellation size | |
| Total satellites | 24 |
| Satellites in orbit | 29 |
| First launch | October 1982 |
| Last launch | 7 February 2016 |
| Orbital characteristics | |
| Regime(s) | 3x MEO |
| Orbital height | 19,130 km |
A model of a GLONASS-K satellite displayed at CeBit 2011
Manufacturers of GPS devices say that adding GLONASS made more satellites available to them, meaning positions can be fixed more quickly and accurately, especially in built-up areas where the view to some GPS satellites is obscured by buildings. Smartphones generally tend to use the same chipsets and since the versions used since 2015 receive GLONASS signals, smartphones using such chips receive GLONASS positioning information along with GPS. Since 2012, GLONASS was the second most used positioning system in mobile phones after GPS. The system has the advantage that smartphone users receive a more accurate reception of up to 2 meters.[1]
Development of GLONASS began in the Soviet Union in 1976. Beginning on 12 October 1982, numerous rocket launches added satellites to the system until the constellation was completed in 1995. After a decline in capacity during the late 1990s, in 2001, under Vladimir Putin's presidency, the restoration of the system was made a top government priority and funding was substantially increased. GLONASS is the most expensive program of the Russian Federal Space Agency, consuming a third of its budget in 2010.
By 2010, GLONASS had achieved 100% coverage of Russia's territory and in October 2011, the full orbital constellation of 24 satellites was restored, enabling full global coverage. The GLONASS satellites' designs have undergone several upgrades, with the latest version being GLONASS-K.
Contents
HistoryEdit
Main article: History of GLONASS
Inception and designEdit
A GLONASS satellite
The task of designing GLONASS was given to a group of young specialists at NPO PM in the city of Krasnoyarsk-26 (today called Zheleznogorsk). Under the leadership of Vladimir Cheremisin, they developed different proposals, from which the institute's director Grigory Chernyavsky selected the final one. The work was completed in the late 1970s; the system consists of 24 satellites operating at an altitude of 20,000 kilometres (12,000 mi) in medium circular orbit. It would be able to promptly fix the receiving station's position based on signals from four satellites, and also reveal the object's speed and direction. The satellites would be launched three at a time on the heavy-lift Proton rocket. Due to the large number of satellites needed for the program, NPO PM delegated the manufacturing of the satellites to PO Polyot in Omsk, which had better production capabilities.[4][5]
Originally, GLONASS was designed to have an accuracy of 65 metres (213 ft), but in reality it had an accuracy of 20 metres (66 ft) in the civilian signal and 10 metres (33 ft) in the military signal.[6] The first generation GLONASS satellites were 7.8 metres (26 ft) tall, had a width of 7.2 metres (24 ft), measured across their solar panels, and a mass of 1,260 kilograms (2,780 lb).[6]
Achieving full orbital constellationEdit
In the early 1980s, NPO PM received the first prototype satellites from PO Polyot for ground tests. Many of the produced parts were of low quality and NPO PM engineers had to perform substantial redesigning, leading to a delay.[4] On 12 October 1982, three satellites, designated Kosmos-1413, Kosmos-1414, and Kosmos-1415 were launched aboard a Proton rocket. As only one GLONASS satellite was ready in time for the launch instead of the expected three, it was decided to launch it along with two mock-ups. The USA media reported the event as a launch of one satellite and "two secret objects." For a long time, the USA could not find out the nature of those "objects". The Telegraph Agency of the Soviet Union (TASS) covered the launch, describing GLONASS as a system "created to determine positioning of civil aviation aircraft, navy transport and fishing-boats of the Soviet Union".[4]From 1982 to April 1991, the Soviet Union successfully launched a total of 43 GLONASS-related satellites plus five test satellites. When the Soviet Union disintegrated in 1991, twelve GLONASS satellites in two planes were operational; enough to allow limited use of the system (to cover the entire territory of the Union, 18 satellites would have been necessary.) The Russian Federation took over control of the constellation and continued its development.[5] In 1993, the system, now consisting of 12 satellites, was formally declared operational[7] and in December 1995 it was brought to a fully operational constellation of 24 satellites. This brought the precision of GLONASS on a par with the USA GPS system, which had achieved full operation а year earlier.[5]
Economic crisisEdit
Since the first generation satellites operated for three years each, to keep the system at full capacity, two launches per year would have been necessary to maintain the full network of 24 satellites. However, in the financially difficult period of 1989–1999, the space program's funding was cut by 80% and Russia consequently found itself unable to afford this launch rate. After the full complement was achieved in December 1995, there were no further launches until December 1999. As a result, the constellation reached its lowest point of just six operational satellites in 2001. As a prelude to demilitarisation, responsibility of the program was transferred from the Ministry of Defence to Russia's civilian space agency Roscosmos.[6]Renewed efforts and modernizationEdit
President Vladimir Putin with a GLONASS car navigation device. As President, Putin paid special attention to the development of GLONASS.
On 10 December 2003, the second generation satellite design, GLONASS-M, was launched for the first time. It had a slightly larger mass than the baseline GLONASS, standing at 1,415 kilograms (3,120 lb), but it had seven years lifetime, four years longer than the lifetime of the original GLONASS satellite, decreasing the required replacement rate. The new satellite also had better accuracy and ability to broadcast two extra civilian signals.
In 2006, Defence Minister Sergey Ivanov ordered one of the signals (with an accuracy of 30 metres (98 ft)) to be made available to civilian users. Putin, however, was not satisfied with this, and demanded that the whole system should be made fully available to everyone. Consequently, on 18 May 2007, all restrictions were lifted.[7][10] The accurate, formerly military-only signal with a precision of 10 metres (33 ft), has since then been freely available to civilian users.
During the middle of the first decade of the 21st century, the Russian economy boomed, resulting in substantial increases in the country's space budget. In 2007, the financing of the GLONASS program was increased considerably; its budget was more than doubled. While in 2006 the GLONASS had received $181 million from the federal budget, in 2007 the amount was increased to $380 million.[7]
In the end, 140.1 billion rubles ($4.7 billion) were spent on the program 2001–2011, making it Roscosmos' largest project and consuming a third of its 2010 budget of 84.5 billion rubles.[11]
For the period of 2012 to 2020 320 billion rubles ($10 billion) were allocated to support the system.[12]
Restoring full capacityEdit
In June 2008, the system consisted of 16 satellites, 12 of which were fully operational at the time. At this point, Roscosmos aimed at having a full constellation of 24 satellites in orbit by 2010, one year later than previously planned.[13]In September 2008, Prime Minister Vladimir Putin signed a decree allocating additional 67 billion rubles ($2.6 billion) to GLONASS from the federal budget.[14]
Promoting commercial useEdit
Although the GLONASS constellation has reached global coverage, its commercialisation, especially development of the user segment, has been lacking compared to the American GPS. For example, the first commercial Russian-made GLONASS navigation device for cars, Glospace SGK-70, was introduced in 2007, but it was much bigger and costlier than similar GPS receivers.[8] In late 2010, there were only a handful of GLONASS receivers on the market, and few of them were meant for ordinary consumers. To improve the situation, the Russian government has been actively promoting GLONASS for civilian use.[15]To improve development of the user segment, on 11 August 2010, Sergei Ivanov announced a plan to introduce a 25% import duty on all GPS-capable devices, including mobile phones, unless they are compatible with GLONASS. The government also planned to force all car manufacturers in Russia to support GLONASS starting from 2011. This would affect all car makers, including foreign brands like Ford and Toyota, which have car assembly facilities in Russia.[16]
GPS and phone baseband chips from major vendors Qualcomm, Exynos and Broadcom[17] all support GLONASS in combination with GPS.
In April 2011, Sweden's Swepos—a national network of satellite reference stations that provides real-time positioning data with meter accuracy—became the first known foreign company to use GLONASS.[18]
Smartphones and Tablets also saw implementation of GLONASS support in 2011 with devices released that year from Xiaomi Tech Company (Xiaomi Phone 2), Sony Ericsson, Samsung (Galaxy Note Galaxy Note II, Galaxy SII, the Google Nexus 10 in late 2012), Asus, Apple (iPhone 4S and iPad Mini in late 2012) and HTC adding support for the system allowing increased accuracy and lock on speed in difficult conditions.[19][20][21] For a more complete list of smartphones see List of smartphones using GLONASS Navigation and for a more complete list of tablets see the text GLONASS in the GPS column in the Comparison of tablet computers.
Finishing the constellationEdit
Russia's aim of finishing the constellation in 2010 suffered a setback when a December 2010 launch of three GLONASS-M satellites failed. The Proton-M rocket itself performed flawlessly, but the upper stage Blok DM3 (a new version that was to make its maiden flight) was loaded with too much fuel due to a sensor failure. As a result, the upper stage and the three satellites crashed into the Pacific Ocean. Kommersant estimated that the launch failure cost up to $160 million.[22] Russian President Dmitry Medvedev ordered a full audit of the entire program and an investigation into the failure.[23]Following the mishap, Roscosmos activated two reserve satellites and decided to make the first improved GLONASS-K satellite, to be launched in February 2011, part of the operational constellation instead of mainly for testing as was originally planned. This would bring the total number of satellites to 23, obtaining almost complete worldwide coverage.[24] The GLONASS-K2 was originally scheduled to be launched by 2013, however by 2012 was not expected to be launched until 2015.[25]
In 2010, President Dmitry Medvedev ordered the government to prepare a new federal targeted program for GLONASS, covering the years 2012–2020. The original 2001 program is scheduled to end in 2011.[22] On 22 June 2011, Roscosmos revealed that the agency was looking for a funding of 402 billion rubles ($14.35 billion) for the program. The funds would be spent on maintaining the satellite constellation, on developing and maintaining navigational maps as well as on sponsoring supplemental technologies to make GLONASS more attractive to users.[26]
On 2 October 2011 the 24th satellite of the system, a GLONASS-M, was successfully launched from Plesetsk Cosmodrome and is now in service.[27] This made the GLONASS constellation fully restored, for the first time since 1996.[28]
On 5 November 2011 the Proton-M booster successfully put three GLONASS-M units in final orbit.[29]
On Monday 28 November 2011, a Soyuz rocket, launched from the Plesetsk Cosmodrome Space Centre, placed a single GLONASS-M satellite into orbit into Plane 3.
On 26 April 2013 a single GLONASS-M satellite was delivered to the orbit by Soyuz rocket from Plesetsk Cosmodrome, restoring the constellation to 24 operational satellites, the minimum to provide global coverage.[30]
On 2 July 2013 a Proton-M rocket, carrying 3 GLONASS-M satellites, crashed during takeoff from Baikonur Cosmodrome. It veered off the course just after leaving the pad and plunged into the ground nose first. The rocket employed a DM-03 booster, for the first time since the December 2010 launch, when the vehicle had also failed, resulting in a loss of another 3 satellites.[31]
However, as of 2014, while the system was completed from technical point of view, the operational side was still not closed by the Ministry of Defense and its formal status was still "in development".[32]
On 7 December 2015, the system was officially completed.[33]
System descriptionEdit
Comparison of geostationary, GPS, GLONASS, Galileo, Compass (MEO), International Space Station, Hubble Space Telescope and Iridium constellation orbits, with the Van Allen radiation belts and the Earth to scale.[a] The Moon's orbit is around 9 times larger than geostationary orbit.[b] (In the SVG file, hover over an orbit or its label to highlight it; click to load its article.)
SignalEdit
FDMAEdit
A Russian military rugged, combined GLONASS/GPS receiver
The signals use similar DSSS encoding and binary phase-shift keying (BPSK) modulation as in GPS signals. All GLONASS satellites transmit the same code as their standard-precision signal; however each transmits on a different frequency using a 15-channel frequency division multiple access (FDMA) technique spanning either side from 1602.0 MHz, known as the L1 band. The center frequency is 1602 MHz + n × 0.5625 MHz, where n is a satellite's frequency channel number (n=−7,−6,−5,...0,...,6, previously n=0,...,13). Signals are transmitted in a 38° cone, using right-hand circular polarization, at an EIRP between 25 and 27 dBW (316 to 500 watts). Note that the 24-satellite constellation is accommodated with only 15 channels by using identical frequency channels to support antipodal (opposite side of planet in orbit) satellite pairs, as these satellites are never both in view of an earth-based user at the same time.
The L2 band signals use the same FDMA as the L1 band signals, but transmit straddling 1246 MHz with the center frequency 1246 MHz + n×0.4375 MHz, where n spans the same range as for L1.[36] In the original GLONASS design, only obfuscated high-precision signal was broadcast in the L2 band, but starting with GLONASS-M, an additional civil reference signal L2OF is broadcast with an identical standard-precision code to the L1OF signal.
A combined GLONASS/GPS Personal Radio Beacon
The navigational message is modulated at 50 bits per second. The superframe of the open signal is 7500 bits long and consists of 5 frames of 30 seconds, taking 150 seconds (2.5 minutes) to transmit the continuous message. Each frame is 1500 bits long and consists of 15 strings of 100 bits (2 seconds for each string), with 85 bits (1.7 seconds) for data and check-sum bits, and 15 bits (0.3 seconds) for time mark. Strings 1-4 provide immediate data for the transmitting satellite, and are repeated every frame; the data include ephemeris, clock and frequency offsets, and satellite status. Strings 5-15 provide non-immediate data (i.e. almanac) for each satellite in the constellation, with frames I-IV each describing five satellites, and frame V describing remaining four satellites.
The ephemerides are updated every 30 minutes using data from the Ground Control segment; they use Earth Centred Earth Fixed (ECEF) Cartesian coordinates in position and velocity, and include lunisolar acceleration parameters. The almanac uses modified Keplerian parameters and is updated daily.
The more accurate high-precision signal is available for authorized users, such as the Russian Military, yet unlike the US P(Y) code, which is modulated by an encrypting W code, the GLONASS restricted-use codes are broadcast in the clear using only security through obscurity. The details of the high-precision signal have not been disclosed. The modulation (and therefore the tracking strategy) of the data bits on the L2SF code has recently changed from unmodulated to 250 bit/s burst at random intervals. The L1SF code is modulated by the navigation data at 50 bit/s without a Manchester meander code.
The high-precision signal is broadcast in phase quadrature with the standard-precision signal, effectively sharing the same carrier wave, but with a ten-times-higher bandwidth than the open signal. The message format of the high-precision signal remains unpublished, although attempts at reverse-engineering indicate that the superframe is composed of 72 frames, each containing 5 strings of 100 bits and taking 10 seconds to transmit, with total length of 36 000 bits or 720 seconds (12 minutes) for the whole navigational message. The additional data are seemingly allocated to critical Luni-Solar acceleration parameters and clock correction terms.
AccuracyEdit
At peak efficiency, the standard-precision signal offers horizontal positioning accuracy within 5–10 meters, vertical positioning within 15 metres (49 ft), a velocity vector measuring within 10 centimetres per second (3.9 in/s), and timing within 200 ns, all based on measurements from four first-generation satellites simultaneously;[37] newer satellites such as GLONASS-M improve on this.GLONASS uses a coordinate datum named "PZ-90" (Earth Parameters 1990 – Parametry Zemli 1990), in which the precise location of the North Pole is given as an average of its position from 1990 to 1995. This is in contrast to the GPS's coordinate datum, WGS 84, which uses the location of the North Pole in 1984. As of 17 September 2007 the PZ-90 datum has been updated to version PZ-90.02 which differ from WGS 84 by less than 40 cm (16 in) in any given direction. Since 31 December 2013, version PZ-90.11 is being broadcast, which is aligned to the International Terrestrial Reference System at epoch 2011.0 at the centimeter level.[38][39]
CDMAEdit
Since 2008, new CDMA signals are being researched for use with GLONASS.[40][41][42][43][44][45][46][47]According to preliminary statements from GLONASS developers, there will be three open and two restricted CDMA signals. The open signal L3OC is centered at 1202.025 MHz and uses BPSK(10) modulation for both data and pilot channels; the ranging code transmits at 10.23 million chips per second, modulated onto the carrier frequency using QPSK with in-phase data and quadrature pilot. The data is error-coded with 5-bit Barker code and the pilot with 10-bit Neuman-Hoffman code.[48][49]
Open L1OC and restricted L1SC signals are centered at 1600.995 MHz, and open L2OC and restricted L2SC signals are centered at 1248.06 MHz, overlapping with GLONASS FDMA signals. Open signals L1OC and L2OC use time-division multiplexing to transmit pilot and data signals, with BPSK(1) modulation for data and BOC(1,1) modulation for pilot; wide-band restricted signals L1SC and L2SC use BOC (5, 2.5) modulation for both data and pilot, transmitted in quadrature phase to the open signals; this places peak signal strength away from the center frequency of narrow-band open signals.[46][50]
Binary phase-shift keying (BPSK) is used by standard GPS and GLONASS signals, however both BPSK and quadrature phase-shift keying (QPSK) can be considered as variations of quadrature amplitude modulation (QAM), specifically QAM-2 and QAM-4. Binary offset carrier (BOC) is the modulation used by Galileo, modernized GPS, and COMPASS.
The navigational message of the L3OC signal is transmitted at 100 bit/s. The navigational frame is 15 seconds (1500 bits) long and includes 5 strings of symbols each taking 3 seconds (300 bits); a frame contains ephemerides for the current satellite and part of the almanac for three satellites. The superframe consists of 8 navigational frames, so it takes 120 seconds (2 minutes) to transmit 12000 bits of almanac for all current 24 satellites. In the future, the superframe will be expanded to 10 frames or 15000 bits (150 seconds or 2.5 minutes) of data to cover full 30 satellites. The system time marker is transmitted with each string; UTC leap second correction is achieved by shortening or lengthening (zero-padding) the final string of the day by one second (100 bits), with shortened strings being discarded by the receiver.[51] The strings have a version tag to facilitate forward compatibility: future upgrades to the message format will not break older equipment, which will continue to work by ignoring new data (as long as the constellation still transmits old string types), but up-to-date equipment will be able to use additional information from newer satellites.[52]
| Satellite series | Launch | Current status | Clock error | FDMA signals | CDMA signals | Interoperability CDMA signals | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1602 + n×0.5625 MHz | 1246 + n×0.4375 MHz | 1600.995 MHz | 1248.06 MHz | 1202.025 MHz | 1575.42 MHz | 1207.14 MHz | 1176.45 MHz | ||||
| GLONASS | 1982–2005 | Out of service | 5×10−13 | L1OF, L1SF | L2SF | ||||||
| GLONASS-M | 2003–2016 | In service | 1×10−13 | L1OF, L1SF | L2OF, L2SF | ||||||
| GLONASS-K1 | 2011, 2014 | In service | 5×10−14...1×10−13 | L1OF, L1SF | L2OF, L2SF | L3OС | |||||
| GLONASS-K2 | 2018–2024 | Design phase | 5×10−14 | L1OF, L1SF | L2OF, L2SF | L1OC, L1SC | L2SC | L3OC | |||
| GLONASS-KМ | 2025– | Research phase | L1OF, L1SF | L2OF, L2SF | L1OC, L1SC | L2OC, L2SC | L3OC, L3SC | L1OCM | L3OCM | L5OCM | |
| "O": open signal (standard precision), "S": obfuscated signal (high precision); "F":FDMA, "С":CDMA; n=−7,−6,−5,...,6 | |||||||||||
Glonass-K2 satellites, to be launched in 2018, will feature a full suite of modernized CDMA signals in the existing L1 and L2 bands, which includes L1SC, L1OC, and L2SC, as well as the L3OC signal. Glonass-K2 should gradually replace existing satellites starting from 2017, when Glonass-M launches will cease.[53]
Glonass-KM satellites will be launched by 2025. Additional open signals are being studied for these satellites, based on the same frequencies and formats as GPS signals L5 and L1C and corresponding Galileo/COMPASS signals E1, E5a and E5b. These signals include:
- The open signal L1OCM will use BOC(1,1) modulation centered at 1575.42 MHz, similar to modernized GPS signal L1C and Galileo/COMPASS signal E1;
- The open signal L5OCM will use BPSK(10) modulation centered at 1176.45 MHz, similar to the GPS "Safety of Life" (L5) and Galileo/COMPASS signal E5a;[54]
- The open signal L3OCM will use BPSK(10) modulation centered at 1207.14 MHz, similar to Galileo/COMPASS signal E5b.[42]
With the introduction of CDMA signals, the constellation will be expanded to 30 active satellites by 2025; this may require eventual deprecation of FDMA signals.[55] The new satellites will be deployed into three additional planes, bringing the total to six planes from the current three—aided by System for Differential Correction and Monitoring (SDCM), which is a GNSS augmentation system based on a network of ground-based control stations and communication satellites Luch 5A and Luch 5B.[56][57] Additional satellites may use Molniya orbit, Tundra orbit, geosynchronous orbit, or inclined orbit to offer increased regional availability, similar to Japanese QZSS system.[42][51]
SatellitesEdit
See also: List of GLONASS satellites
The main contractor of the GLONASS program is Joint Stock Company Reshetnev Information Satellite Systems (ISS Reshetnev, formerly called NPO-PM). The company, located in Zheleznogorsk, is the designer of all GLONASS satellites, in cooperation with the Institute for Space Device Engineering (ru:РНИИ КП) and the Russian Institute of Radio Navigation and Time. Serial production of the satellites is accomplished by the company PC Polyot in Omsk.Over the three decades of development, the satellite designs have gone through numerous improvements, and can be divided into three generations: the original GLONASS (since 1982), GLONASS-M (since 2003) and GLONASS-K (since 2011). Each GLONASS satellite has a GRAU designation 11F654, and each of them also has the military "Cosmos-NNNN" designation.[58]
First generationEdit
Main article: GLONASS (satellite)
The true first generation of GLONASS (also called Uragan) satellites
were all three-axis stabilized vehicles, generally weighing 1,250
kilograms (2,760 lb) and were equipped with a modest propulsion system
to permit relocation within the constellation. Over time they were
upgraded to Block IIa, IIb, and IIv vehicles, with each block containing
evolutionary improvements.Six Block IIa satellites were launched in 1985–1986 with improved time and frequency standards over the prototypes, and increased frequency stability. These spacecraft also demonstrated a 16-month average operational lifetime. Block IIb spacecraft, with a two-year design lifetimes, appeared in 1987, of which a total of 12 were launched, but half were lost in launch vehicle accidents. The six spacecraft that made it to orbit worked well, operating for an average of nearly 22 months.
Block IIv was the most prolific of the first generation. Used exclusively from 1988 to 2000, and continued to be included in launches through 2005, a total of 25 satellites were launched. The design life was three years, however numerous spacecraft exceeded this, with one late model lasting 68 months.[59]
Block II satellites were typically launched three at a time from the Baikonur Cosmodrome using Proton-K Blok-DM-2 or Proton-K Briz-M boosters. The only exception was when, on two launches, an Etalon geodetic reflector satellite was substituted for a GLONASS satellite.
Second generationEdit
Main article: GLONASS-M
The second generation of satellites, known as Glonass-M, were
developed beginning in 1990 and first launched in 2003. These satellites
possess a substantially increased lifetime of seven years and weigh
slightly more at 1,480 kilograms (3,260 lb). They are approximately
2.4 m (7 ft 10 in) in diameter and 3.7 m (12 ft) high, with a solar
array span of 7.2 m (24 ft) for an electrical power generation
capability of 1600 watts at launch. The aft payload structure houses 12
primary antennas for L-band transmissions. Laser corner-cube reflectors
are also carried to aid in precise orbit determination and geodetic
research. On-board cesium clocks
provide the local clock source. Glonass-M consisting 31 satellites
ranging from satellite index 21 - 92 and with 4 spare active satellites.A total of 41 second generation satellites were launched through the end of 2013. As with the previous generation, the second generation spacecraft were launched in triplets using Proton-K Blok-DM-2 or Proton-K Briz-M boosters. Some where launched alone with Soyuz-2-1b/Fregat
On July 30, 2015, ISS Reshetnev announced that it had completed the last GLONASS-M (N° 61) spacecraft and it was putting it in storage waiting for launch, along an additional eight already built satellites.[60][61]
Third generationEdit
Main article: GLONASS-K
GLONASS-K is a substantial improvement of the previous generation: it
is the first unpressurised GLONASS satellite with a much reduced mass
(750 kilograms (1,650 lb) versus 1,450 kilograms (3,200 lb) of
GLONASS-M). It has an operational lifetime of 10 years, compared to the
7-year lifetime of the second generation GLONASS-M. It will transmit
more navigation signals to improve the system's accuracy—including new
CDMA signals in the L3 and L5 bands, which will use modulation similar
to modernized GPS, Galileo, and Compass. Glonass-K consist of 26
satellites having satellite index 65-98 and widely used in Russian
Military space.[62][63][64] The new satellite's advanced equipment—made solely from Russian components—will allow the doubling of GLONASS' accuracy.[34] As with the previous satellites, these are 3-axis stabilized, nadir pointing with dual solar arrays.[citation needed] The first GLONASS-K satellite was successfully launched on 26 February 2011.[62][65]Due to their weight reduction, GLONASS-K spacecraft can be launched in pairs from the Plesetsk Cosmodrome launch site using the substantially lower cost Soyuz-2.1b boosters or in six-at-once from the Baikonur Cosmodrome using Proton-K Briz-M launch vehicles.[34][35]
Ground controlEdit
The ground control segment of GLONASS is almost entirely located within former Soviet Union territory, except for a station in Brasilia, Brazil.[66] The Ground Control Center and Time Standards is located in Moscow and the telemetry and tracking stations are in Saint Petersburg, Ternopil, Eniseisk and Komsomolsk-na-Amure.[67]ReceiversEdit
Septentrio, Topcon, C-Nav, JAVAD, Magellan Navigation, Novatel, Leica Geosystems, Hemisphere GNSS and Trimble Inc produce GNSS receivers making use of GLONASS. NPO Progress describes a receiver called GALS-A1, which combines GPS and GLONASS reception. SkyWave Mobile Communications manufactures an Inmarsat-based satellite communications terminal that uses both GLONASS and GPS.[68] As of 2011, some of the latest receivers in the Garmin eTrex line also support GLONASS (along with GPS).[69] Garmin also produce a standalone Bluetooth receiver, the GLOTM for Aviation, which combines GPS, WAAS and GLONASS.[70] Various smartphones from 2011 onwards have integrated GLONASS capability, including devices from Xiaomi Tech Company (Xiaomi Phone 2), Sony Ericsson,[71] ZTE, Huawei,[72] Samsung (Galaxy Note, Galaxy Note II, Galaxy S3, Galaxy S4),[73] Apple (iPhone 4S, iPhone 5, iPhone 5C, iPhone 5S, iPhone 6 and iPhone 6 Plus, iPhone 6s, iPhone 6s Plus, and iPhone SE),[74] iPad Mini (LTE models only), iPad Mini 2 (LTE models only), iPad Mini 3 (LTE models only), iPad Mini 4 (LTE models only)[75] iPad (3rd generation and 4th Generation, 4G and LTE models only [respectively]), iPad Air (LTE models only) and iPad Air 2 (LTE models only) and Apple's flagship iPad Pro 12.9" and 9.7",[76] HTC,[77] LG,[78] Motorola[79] and Nokia.[80]StatusEdit
AvailabilityEdit
As of 16 May 2016, the GLONASS constellation status is:| Total | 28 SC |
|---|---|
| Operational | 24 SC (Glonass-M/K) |
| In commissioning | 0 SC |
| In maintenance | 0 SC |
| Under check by the Satellite Prime Contractor | 2 SC |
| Spares | 1 SC (Glonass-M) |
| In flight tests phase | 1 SC (Glonass-K) |
| – |
On 2 April 2014 the system experienced a technical failure that resulted in practical unavailability of the navigation signal for around 12 hours.[32]
On 14–15 April 2014 nine GLONASS satellites experienced a technical failure due to software problems.[82]
On 19 February 2016 three GLONASS satellites experienced a technical failure: the batteries of GLONASS-738 exploded, the batteries of GLONASS-737 were depleted, and GLONASS-736 experienced a stationkeeping failure due to human error during maneuvering. GLONASS-737 and GLONASS-736 are expected to be operational again after maintenance, and one new satellite (GLONASS-751) to replace GLONASS-738 is expected to complete commissioning in early March. The full capacity of the satellite group is expected to be restored in the middle of March.[83]
AccuracyEdit
According to Russian System of Differentional Correction and Monitoring's data, as of 2010, precisions of GLONASS navigation definitions (for p=0.95) for latitude and longitude were 4.46–7.38 metres (14.6–24.2 ft) with mean number of navigation space vehicles (NSV) equals 7—8 (depending on station). In comparison, the same time precisions of GPS navigation definitions were 2.00–8.76 metres (6 ft 7 in–28 ft 9 in) with mean number of NSV equals 6—11 (depending on station).[citation needed] Civilian GLONASS used alone is therefore very slightly less accurate than GPS. On high latitudes (north or south), GLONASS' accuracy is better than that of GPS due to the orbital position of the satellites.[84]Some modern receivers are able to use both GLONASS and GPS satellites together, providing greatly improved coverage in urban canyons and giving a very fast time to fix due to over 50 satellites being available. In indoor, urban canyon or mountainous areas, accuracy can be greatly improved over using GPS alone. For using both navigation systems simultaneously, precisions of GLONASS/GPS navigation definitions were 2.37–4.65 metres (7 ft 9 in–15 ft 3 in) with mean number of NSV equals 14—19 (depends on station).
In May 2009, Anatoly Perminov, then director of the Russian Federal Space Agency, stated that actions were undertaken to expand GLONASS's constellation and to improve the ground segment to increase the navigation definition of GLONASS to an accuracy of 2.8 metres (9 ft 2 in) by 2011.[85] In particular, the latest satellite design, GLONASS-K has the ability to double the system's accuracy once introduced. The system's ground segment is also to undergo improvements. As of early 2012, sixteen positioning ground stations are under construction in Russia and in the Antarctic at the Bellingshausen and Novolazarevskaya bases. New stations will be built around the southern hemisphere from Brazil to Indonesia. Together, these improvements are expected to bring GLONASS' accuracy to 0.6 m or better by 2020.[86]
See alsoEdit
- List of GLONASS satellites
- List of smartphones using GLONASS Navigation
- Global navigation satellite system – the generic phrase for a global satellite positioning system
- Multilateration – the mathematical technique used for positioning
- Tsikada – a Russian satellite navigation system
- Aviaconversiya – a Russian satellite navigation firm
- Era-glonass – GLONASS-based system of emergency response
NotesEdit
- ^ Orbital periods and speeds are calculated using the relations 4π²R³ = T²GM and V²R = GM, where R = radius of orbit in metres, T = orbital period in seconds, V = orbital speed in m/s, G = gravitational constant ≈ 6.673×10−11 Nm²/kg², M = mass of Earth ≈ 5.98×1024 kg.
- ^ Approximately 8.6 times (in radius and length) when the moon is nearest (363 104 km ÷ 42 164 km) to 9.6 times when the moon is farthest (405 696 km ÷ 42 164 km).
ReferencesEdit
- ^ GLONASS the future for all smartphones?
- ^ "Tsiklon". Encyclopedia Astronautica.
- ^ "Glonass". Encyclopedia Astronautica.
- ^ a b c "Start of GLONASS" (PDF). ISS Reshetnev. 2007.
- ^ a b c "Satellite Navigation of the 21st Century" (PDF). ISS Reshetnev. 2009.
- ^ a b c d e Harvey, Brian (2007). "Military programs". The Rebirth of the Russian Space Program (1st ed.). Germany: Springer. ISBN 978-0-387-71354-0.
- ^ a b c "Putin makes Glonass navigation system free for customers – 1". RIA Novosti. 2007-05-18.
- ^ a b c Moskvitch, Katia (2010-04-02). "Glonass: Has Russia's sat-nav system come of age?". BBC News.
- ^ Glonass still wants to be "the other guy in the sky. RT. 6 December 2010. Retrieved on 2011-10-06.
- ^ "Russia to lift Glonass restrictions for accurate civilian use". RIA Novosti. 2006-11-13.
- ^ GLONASS hits a snag. Russia Beyond The Headlines. 7 December 2010. Retrieved on 2011-10-06.
- ^ "Работа в интересах развития ГЛОНАСС" [Work for the development of GLONASS] (№30(318)). Сибирский спутник [Siberian Satellite]. 2012-09-14. p. 3. Archived from the original (PDF) on 2013-05-15. Retrieved 2013-05-12.
- ^ "Russia's Glonass satellite system to be fully operational in 2010". RIA Novosti. 2008-06-07.
- ^ "Putin orders additional $2.6 bln on Glonass development". RIA Novosti. 2008-09-12.
- ^ "Glonass still wants to be "the other guy in the sky"". Russia Today. 2010-12-07.
- ^ Сотовые и навигаторы без ГЛОНАСС обложат пошлиной в 25% [Non-GLONASS-capable mobiles and satnavs will incur 25% duty] (in Russian). RBC Information Systems. 2010-10-27. Retrieved 2010-10-27.
- ^ Broadcom Upgrades Its A-GPS Data Service and GPS LTO Product/Service with GLONASS Satellite Support. Broadcom.com (2011-02-09). Retrieved on 2011-10-06.
- ^ "Swedish firm starts using Russian satnav". Reuters. 2011-04-11. Archived from the original on 2012-01-25.
- ^ GLONASS support in our latest Xperia™ phones – Developer World. Developer.sonyericsson.com. Retrieved on 2013-08-02.
- ^ Samsung GALAXY Note - Samsung Mobile. Samsung.com. Retrieved on 2013-08-02.
- ^ iPhone 5 - View all the technical specifications. Apple. Retrieved on 2013-08-02.
- ^ a b "GLONASS hits a snag". Kommersant. 2010-12-07.
- ^ Weir, Fred (6 December 2010). "Russia's $2 billion project to rival America's GPS suffers setback". Christian Science Monitor.
- ^ Perminov, Anatoly (7 December 2010). "Interview of Anatoly Perminov to the Izvestia Newspaper" (in Russian). Roscosmos.
- ^ "GLONASS network". 2013-07-11. Retrieved 2013-10-24.
- ^ "Glonass Asks for $14.35Bln". The Moscow Times. 22 June 2011.
- ^ GLONASS finally becomes global NTV. 3 October 2011. (Russian)
- ^ Russia restores its orbital GLONASS group – official. The Voice of Russia. 3 October 2011. (Russian)
- ^ "TASS: Archive - 3 GLONASS satellites in final orbit". TASS. Retrieved 2 September 2015.
- ^ "Third Soyuz launch in a week bolsters Glonass system". 2013-04-26. Retrieved 2013-07-02.
- ^ "Russia's Proton crashes with a trio of navigation satellites". 2013-07-02. Retrieved 2013-07-02.
- ^ a b "Роскосмос ищет причины сбоя ГЛОНАСС". Izvestia. 2014.
- ^ https://lenta.ru/news/2015/12/07/glonass/
- ^ a b c d Afanasyev, Igor; Dmitri Vorontsov (2010-11-26). "Glonass nearing completion". Russia & CIS Observer.
- ^ a b c "The Global Navigation System GLONASS: Development and Usage in the 21st Century" (PDF). 34th Annual Precise Time and Time Interval (PTTI) Meeting. 2002.
- ^ GLONASS transmitter specs
- ^ "A Review of GLONASS" Miller, 2000
- ^ National Reference Systems of the Russian Federation used in GLONASS. V. Vdovin and M. Vinogradova (TSNIImash), 8th ICG meeting, Dubai, November 2013
- ^ "The transition to using the terrestrial geocentric coordinate system "Parametry Zemli 1990" (PZ-90.11) in operating the GLObal NAvigation Satellite System (GLONASS) has been implemented". glonass-iac.ru. Retrieved 2 September 2015.
- ^ "Russia Approves CDMA Signals for GLONASS, Discussing Common Signal Design". Inside GNSS. Retrieved 2010-12-30.
- ^ GLONASS Status and Progress, S.G.Revnivykh, 47th CGSIC Meeting, 2007. "L1CR and L5R CDMA interoperable with GPS and Galileo"
- ^ a b c GLONASS Status and Development, G.Stupak, 5th ICG Meeting
- ^ Russia’s First GLONASS-K In Orbit, CDMA Signals Coming. Inside GNSS (2011-02-26). Retrieved on 2011-10-06.
- ^ GLONASS Status and Modernization. Ekaterina Oleynik, Sergey Revnivykh, 51st CGSIG Meeting, September 2011
- ^ GLONASS Status and Modernization. Sergey Revnivykh. 6th ICG Meeting, September 2011
- ^ a b GLONASS Status and Modernization. Sergey Revnivykh. 7th ICG Meeting, November 2012
- ^ GLONASS Government Policy, Status and Modernization Plans. Tatiana Mirgorodskaya. IGNSS-2013, 16 July 2013
- ^ "GLONASS Modernization". GPS World. Retrieved 2 September 2015.
- ^ http://www.insidegnss.com/auto/julyaug11-Dumas.pdf
- ^ GLONASS Modernization Yuri Urlichich, Valery Subbotin, Grigory Stupak, Vyacheslav Dvorkin, Alexander Povalyaev, Sergey Karutin, and Rudolf Bakitko, Russian Space Systems. GPS World, November 2011
- ^ a b GLONASS: Developing Strategies for the Future. Yuri Urlichich, Valeriy Subbotin, Grigory Stupak, Vyacheslav Dvorkin, Alexander Povalyaev, and Sergey Karutin. GPS World, November 2011
- ^ New Structure for GLONASS Nav Message Alexander Povalyaev. GPS World, 2 November 2013
- ^ a b Testoyedov, Nikolay (2015-05-18). "Space Navigation in Russia: History of Development" (PDF). Retrieved 2015-07-15.
- ^ "Russia to Put 8 CDMA Signals on 4 GLONASS Frequencies". Inside GNSS. 2010-03-17. Retrieved 2010-12-30.
- ^ "GLONASS Update Delves into Constellation Details". GPS World. Retrieved 2010-12-30.
- ^ "GLONASS Modernization: Maybe Six Planes, Probably More Satellites". GPS World. 10 January 2012.
- ^ SDCM status and plans, Grigory Stupak, 7th ICG Meeting, November 2012
- ^ Uragan, Russian Space Web
- ^ GLONASS #787, 68.7 operational months; as reported by RSA "GLONASS constellation status" on 6 April 2007
- ^ "Glonass-M – a chapter in the history of satellite navigation". JSC Information Satellite Systems. 2015-07-30. Retrieved 2015-08-13.
- ^ "Russia stops manufacturing of Glonass-M navigation satellites". ITAR-TASS. 2015-07-30. Retrieved 2015-08-20.
- ^ a b "Glonass-K: a prospective satellite of the GLONASS system" (PDF). Reshetnev Information Satellite Systems. 2007.
- ^ "Russia to launch Glonass satellite on Feb. 24". RIA Novosti. 2011-02-09.
- ^ Langley, Richard (2010). "GLONASS forecast bright and plentiful". GPS World.
- ^ "Russia launches satellite for global navigation system". BBC News. 2011-02-26.
- ^ "Brazil Hosts Russian Satellite Navigation System". The New York Times. 2013-02-19.
- ^ GLONASS Summary, Space and Tech
- ^ "GLONASS added to SkyWave terminals", Digital Ship, 4 December 2009. Thedigitalship.com
- ^ [Garmin eTrex 20 https://buy.garmin.com/shop/shop.do?cID=145&pID=87771#overviewTab]
- ^ GLO for Aviation | Garmin. Buy.garmin.com. Retrieved on 2013-08-02.
- ^ "Sony Xperia™ support (English)" (PDF). sonyericsson.com. Retrieved 2 September 2015.
- ^ "Sony Ericsson и Huawei готовят смартфоны с ГЛОНАСС". CNews.ru. Retrieved 2 September 2015.
- ^ "Samsung GALAXY Note - Samsung Mobile". samsung.com. Retrieved 2 September 2015.
- ^ "iPhone - Compare Models - Apple". Apple. Retrieved 2 September 2015.
- ^ iPad mini - Technical specifications. Apple. Retrieved on 2013-08-02.
- ^ "iPad". Apple. Retrieved 2 September 2015.
- ^ Windows Phone 8X by HTC Overview - HTC Smartphones. Htc.com. Retrieved on 2013-08-02.
- ^ Google Drive Viewer. Docs.google.com. Retrieved on 2013-08-02.
- ^ "The Official Motorola Blog". motorola.com. Retrieved 2 September 2015.
- ^ "GLONASS gets Nokia backing, aims to rival COMPASS". Reuters. Retrieved 2 September 2015.
- ^ Russia to set world record with 39 space launches in 2009 RIA Novosti 2008-12-29
- ^ "Система ГЛОНАСС вышла из строя втоher=Novaya Gazeta". 2014.
- ^ http://izvestia.ru/news/604492
- ^ "First Foreign Firm Embraces Glonass". The Moscow Times. 2011-04-11.
- ^ "Роскосмос обещает повысить точность работы ГЛОНАСС с 10 до 5,5 метров". РИА Новости. Retrieved 2 September 2015.
- ^ Kramnik, Ilya (2012-02-16). "GLONASS benefits worth the extra expense". Russia Beyond the Headlines.
BibliographyEdit
- GLONASS Interface Control Document Edition 5.1, 2008 (backup)
- GLONASS Interface Control Document Version 4.0, 1998
- "ФЕДЕРАЛЬНАЯ ЦЕЛЕВАЯ ПРОГРАММА "ГЛОБАЛЬНАЯ НАВИГАЦИОННАЯ СИСТЕМА" FEDERAL SPECIAL-PURPOSE PROGRAM "GLOBAL NAVIGATION SYSTEM"". Russian Federal Government (in Russian). 2001-08-20. Retrieved 2007-04-10.
- "GLONASS constellation status for 18.01.08 under the analysis of the almanac and accepted in IANC (UTC)". Russian Space Agency (RSA). Retrieved 2008-01-18.
- "GLONASS Summary". Space and Tech. Retrieved 2007-04-12.
- "GLONASS Transmitter Specifications". Archived from the original on 2007-06-13. Retrieved 2007-04-13.
- Goebel, Greg. "Navigation Satellites & GPS". pp. Section 2.2. Retrieved 2007-04-10.
- "Интегральная доступность навигации наземного потребителя по системе ГЛОНАСС Integral accessibility of the navigation of ground-based user along the system GLONASS". Russian Space Agency (RSA) (in Russian). Retrieved 2008-01-18.
- "India joins Russian GPS system". The Times of India. 2007-01-29. Retrieved 2007-04-12.
- "India to Launch 2 Russian GLONASS Satellites". MosNews. 2005-06-27. Retrieved 2007-04-12.
- "Joint announcement (in English and Russian)". GPS/GLONASS Interoperability and Compatibility Working Group. 2006-12-14. Archived from the original on 2007-09-19. Retrieved 2007-04-13.
- Kramer, Andrew E. (2007-04-07). "Russia Challenges the U.S. Monopoly on Satellite Navigation". New York Times. Retrieved 2007-04-12.
- Miller, Keith M. (October 2000). "A Review of GLONASS". Hydrographic Society Journal. Archived from the original on 2007-10-12. Retrieved 2007-04-13.
- "Radical Change in the Air for GLONASS". GPS World. 2007-01-22. Archived from the original on 2007-02-10. Retrieved 2007-04-10.
- "Russia Allocates $380 Million for Global Navigation System in 2007". MosNews. 2007-03-26. Retrieved 2007-04-12.
- "Russia Holds First Place in Spacecraft Launches". MosNews. 2007-03-26. Retrieved 2007-04-12.
- "Russia Launches New Navigation Satellites into Orbit". Space.com / Associated Press. 2007-12-25. Retrieved 2007-12-28.
- "Russian Space Agency Plans Cooperation With India". MosNews. 2004-01-12. Retrieved 2007-04-12.
- "Space Policy Project's "World Space Guide: GLONASS"". Federation of American Scientists. Retrieved 2007-04-10.
- "Услуги системы ГЛОНАСС будут предоставляться потребителям бесплатно The services of system GLONASS will be given to users free of charge" (in Russian). RIA Novosti. 2007-05-18. Retrieved 2007-05-18.
- "Три КА "Глонасс-М" взяты на управление Three KA "GLONASS-M" have taken off". Russian Space Agency (RSA) (in Russian). 2006-12-26. Archived from the original on 2007-09-27. Retrieved 2006-12-29.
- "Uragan (GLONASS, 11F654)". Gunter's Space Page. 2007-01-16. Retrieved 2007-04-10.
- "Uragan navsat (11F654)". Russian Space Web. Retrieved 2007-04-12.
- "GLONASS News". Retrieved 2007-07-31.
External linksEdit
- Official GLONASS web page
- GNSS web page including GLONASS
- Description of GLONASS on the web page of the International Laser Ranging Service (ILRS)
- GLONASS: present, future and past Presented on the ILRS Technical Workshop, 14–19 September 2009, Metsovo, Greece
- A homemade receiver for GPS & GLONASS satellites
- Navipedia information on GLONASS—Wiki initiated by the European Space Agency
Begin quote from:
GNSS.
Satellite navigation
(Redirected from GNSS)
A satellite navigation or satnav system is a system of satellites that provide autonomous geo-spatial positioning with global coverage. It allows small electronic receivers to determine their location (longitude, latitude, and altitude/elevation) to high precision (within a few metres) using time signals transmitted along a line of sight by radio from satellites.
The signals also allow the electronic receiver to calculate the current
local time to high precision, which allows time synchronisation. A
satellite navigation system with global coverage may be termed a global navigation satellite system (GNSS). The system can be used for navigation or for tracking the position of something fitted with a receiver (satellite tracking).
As of April 2013 only the United States NAVSTAR Global Positioning System (GPS) and the Russian GLONASS are global operational GNSSs. China is in the process of expanding its regional BeiDou Navigation Satellite System into the global Compass navigation system by 2020.[1] The European Union's Galileo is a global GNSS in initial deployment phase, scheduled to be fully operational by 2020 at the earliest.[2] India currently has satellite-based augmentation system, GPS Aided GEO Augmented Navigation (GAGAN), which enhances the accuracy of NAVSTAR GPS and GLONASS positions. India has already launched the IRNSS, with an operational name NAVIC (Navigation with Indian Constellation), a constellation of satellites for navigation in and around the Indian Subcontinent. It is expected to be fully operational by June 2016. France and Japan are in the process of developing regional navigation systems as well.
Global coverage for each system is generally achieved by a satellite constellation of 20–30 medium Earth orbit (MEO) satellites spread between several orbital planes. The actual systems vary, but use orbital inclinations of >50° and orbital periods of roughly twelve hours (at an altitude of about 20,000 kilometres or 12,000 miles).
As of April 2013 only the United States NAVSTAR Global Positioning System (GPS) and the Russian GLONASS are global operational GNSSs. China is in the process of expanding its regional BeiDou Navigation Satellite System into the global Compass navigation system by 2020.[1] The European Union's Galileo is a global GNSS in initial deployment phase, scheduled to be fully operational by 2020 at the earliest.[2] India currently has satellite-based augmentation system, GPS Aided GEO Augmented Navigation (GAGAN), which enhances the accuracy of NAVSTAR GPS and GLONASS positions. India has already launched the IRNSS, with an operational name NAVIC (Navigation with Indian Constellation), a constellation of satellites for navigation in and around the Indian Subcontinent. It is expected to be fully operational by June 2016. France and Japan are in the process of developing regional navigation systems as well.
Global coverage for each system is generally achieved by a satellite constellation of 20–30 medium Earth orbit (MEO) satellites spread between several orbital planes. The actual systems vary, but use orbital inclinations of >50° and orbital periods of roughly twelve hours (at an altitude of about 20,000 kilometres or 12,000 miles).
Contents
ClassificationEdit
Satellite navigation systems that provide enhanced accuracy and
integrity monitoring usable for civil navigation are classified as
follows:[3]
- GNSS-1[citation needed] is the first generation system and is the combination of existing satellite navigation systems (GPS and GLONASS), with Satellite Based Augmentation Systems (SBAS) or Ground Based Augmentation Systems (GBAS). In the United States, the satellite based component is the Wide Area Augmentation System (WAAS), in Europe it is the European Geostationary Navigation Overlay Service (EGNOS), and in Japan it is the Multi-Functional Satellite Augmentation System (MSAS). Ground based augmentation is provided by systems like the Local Area Augmentation System (LAAS).[citation needed]
- GNSS-2[citation needed] is the second generation of systems that independently provides a full civilian satellite navigation system, exemplified by the European Galileo positioning system. These systems will provide the accuracy and integrity monitoring necessary for civil navigation; including aircraft. This system consists of L1 and L2 frequencies (in the L band of the radio spectrum) for civil use and L5 for system integrity. Development is also in progress to provide GPS with civil use L2 and L5 frequencies, making it a GNSS-2 system.¹[citation needed]
- Core Satellite navigation systems, currently GPS (United States), GLONASS (Russian Federation), Galileo (European Union) and Compass (China).
- Global Satellite Based Augmentation Systems (SBAS) such as Omnistar and StarFire.
- Regional SBAS including WAAS (US), EGNOS (EU), MSAS (Japan) and GAGAN (India).
- Regional Satellite Navigation Systems such as China's Beidou, India's NAVIC, and Japan's proposed QZSS.
- Continental scale Ground Based Augmentation Systems (GBAS) for example the Australian GRAS and the US Department of Transportation National Differential GPS (DGPS) service.
- Regional scale GBAS such as CORS networks.
- Local GBAS typified by a single GPS reference station operating Real Time Kinematic (RTK) corrections.
History and theoryEdit
The first satellite navigation system was Transit, a system deployed by the US military in the 1960s. Transit's operation was based on the Doppler effect: the satellites travelled on well-known paths and broadcast their signals on a well-known 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 the satellite, and several such measurements combined with a precise knowledge of the satellite's orbit can fix a particular position.
Part of an orbiting satellite's broadcast included its precise orbital data. In order to ensure accuracy, the US Naval Observatory (USNO) continuously observed the precise orbits of these satellites. As a satellite's orbit deviated, the USNO would send the updated information to the satellite. Subsequent broadcasts from an updated satellite would contain the most recent accurate information about its orbit.
Modern systems are more direct. The satellite broadcasts a signal that contains orbital data (from which the position of the satellite can be calculated) and the precise time the signal was transmitted. The orbital data 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 the satellites in the constellation. The receiver compares the time of broadcast encoded in the transmission of three (at sea level) or four different satellites, thereby 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 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 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 the noisy, partial, and constantly changing data into a single estimate for position, time, and velocity.
Civil and military usesEdit
Main article: GNSS applications
The original motivation for satellite navigation was for military
applications. Satellite navigation allows the precision in 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.
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.
Edit
Comparison of geostationary, GPS, GLONASS, Galileo, Compass (MEO), International Space Station, Hubble Space Telescope and Iridium constellation orbits, with the Van Allen radiation belts and the Earth to scale.[a] The Moon's orbit is around 9 times larger than geostationary orbit.[b] (In the SVG file, hover over an orbit or its label to highlight it; click to load its article.)
launched GNSS satellites 1978 to 2014
OperationalEdit
GPSEdit
Main article: Global Positioning System
The United States' Global Positioning System (GPS) consists of up to 32 medium Earth orbit satellites in six different orbital planes,
with the exact number of satellites varying as older satellites are
retired and replaced. Operational since 1978 and globally available
since 1994, GPS is currently the world's most utilized satellite
navigation system.GLONASSEdit
Main article: GLONASS
The formerly Soviet, and now Russian, Global'naya Navigatsionnaya Sputnikovaya Sistema (Russian: ГЛОбальная НАвигационная Спутниковая Система, GLObal NAvigation Satellite System), or GLONASS, was a fully functional navigation constellation in 1995. After the collapse of the Soviet Union,
it fell into disrepair, leading to gaps in coverage and only partial
availability. It was recovered and fully restored in 2011.In developmentEdit
GalileoEdit
Main article: Galileo (satellite navigation)
The European Union and European Space Agency agreed in March 2002 to introduce their own alternative to GPS, called the Galileo positioning system. At an estimated cost of EUR 3.0 billion,[4] the system of 30 MEO satellites was originally scheduled to be operational in 2010. The original year to become operational was 2014.[5] The first experimental satellite was launched on 28 December 2005.[6] 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. Galileo is
now not expected to be in full service until 2020 at the earliest and at
a substantially higher cost.[2] The main modulation used in Galileo Open Service signal is the Composite Binary Offset Carrier (CBOC) modulation.BeiDouEdit
Main article: BeiDou Navigation Satellite System
China
has indicated they plan to complete the entire second generation Beidou
Navigation Satellite System (BDS or BeiDou-2, formerly known as
COMPASS), by expanding current regional (Asia-Pacific) service into
global coverage by 2020.[1] The BeiDou-2 system is proposed to consist of 30 MEO
satellites and five geostationary satellites. A 16-satellite regional
version (covering Asia and Pacific area) was completed by December 2012.Comparison of systemsEdit
| System | GPS | GLONASS | BeiDou | Galileo | NAVIC |
|---|---|---|---|---|---|
| Owner | United States | Russian Federation | China | European Union | India |
| Coding | CDMA | FDMA | CDMA | CDMA | |
| Orbital altitude | 20,180 km (12,540 mi) | 19,130 km (11,890 mi) | 21,150 km (13,140 mi) | 23,222 km (14,429 mi) | 36,000 km (22,000 mi) |
| Period | 11.97 h (11 h 58 min) | 11.26 h (11 h 16 min) | 12.63 h (12 h 38 min) | 14.08 h (14 h 5 min) | |
| Revolutions per sidereal day | 2 | 17/8 | 17/9 | 17/10 | |
| Number of satellites |
32 (at least 24 by design)[7] | 28 (at least 24 by design) including:[8] 24 operational 2 under check by the satellite prime contractor 2 in flight tests phase |
5 geostationary orbit (GEO) satellites, 30 medium Earth orbit (MEO) satellites |
4 in-orbit validation satellites + 8 full operation capable satellites in orbit 22 operational satellites budgeted |
Total : 7
In Orbit : 7 |
| Frequency | 1.57542 GHz (L1 signal) 1.2276 GHz (L2 signal) |
Around 1.602 GHz (SP) Around 1.246 GHz (SP) |
1.561098 GHz (B1) 1.589742 GHz (B1-2) 1.20714 GHz (B2) 1.26852 GHz (B3) |
1.164–1.215 GHz (E5a and E5b) 1.260–1.300 GHz (E6) 1.559–1.592 GHz (E2-L1-E11) |
S-band
(2–4 GHz) |
| Status | Operational | Operational | 22 satellites operational, 40 additional satellites 2016-2020 |
8 satellites operational, 22 additional satellites 2016-2020 |
Operational |
Edit
BeiDou-1Edit
Main article: Beidou Navigation Satellite System
Chinese regional (Asia-Pacific, 16 satellites) network to be expanded
into the whole global system which consists of all 35 satellites by
2020.NAVICEdit
Main article: NAVIC
The NAVIC or NAVigation with Indian Constellation is an autonomous regional satellite navigation system developed by Indian Space Research Organisation (ISRO) which would be under the total control of Indian government.
The government approved the project in May 2006, with the intention of
the system completed and implemented on 28 April 2016. It will consist
of a constellation of 7 navigational satellites.[9] 3 of the satellites will be placed in the Geostationary orbit (GEO) and the remaining 4 in the 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 meters throughout India and within a region extending approximately 1,500 km around it.[10] A goal of complete Indian control has been stated, with the space segment, ground segment and user receivers all being built in India.[11] All seven satellites, IRNSS-1A, IRNSS-1B, IRNSS-1C, IRNSS-1D, IRNSS-1E, IRNSS-1F, and IRNSS-1G,
of the proposed constellation were precisely launched on 1 July 2013, 4
April 2014, 16 October 2014, 28 March 2015, 20 January 2016, 10 March
2016 and 28 April 2016 respectively from Satish Dhawan Space Centre.[12][13] The system is expected to be fully operational by June 2016.[14]QZSSEdit
Main article: Quasi-Zenith Satellite System
The Quasi-Zenith Satellite System (QZSS), is a proposed three-satellite regional time transfer system and enhancement for GPS covering Japan. The first demonstration satellite was launched in September 2010.[15]AugmentationEdit
Main article: GNSS augmentation
Examples of augmentation systems include the Wide Area Augmentation System, the European Geostationary Navigation Overlay Service, the Multi-functional Satellite Augmentation System, Differential GPS, and Inertial Navigation Systems.DORISEdit
Main article: DORIS (geodesy)
Doppler Orbitography and Radio-positioning Integrated by Satellite (DORIS) is a French
precision navigation system. However, 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
(It may be used also for mobile receivers on land with more limited
usage and coverage). Used with traditional GNSS systems, it pushes 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.[16]Low Earth orbit satellite phone networksEdit
The two current operational low Earth orbit satellite phone
networks are able to track transceiver units with accuracy of a few
kilometers using doppler shift calculations from the satellite. The
coordinates are sent back to the transceiver unit where they can be read
using AT commands or a graphical user interface.[17][18] This can also be used by the gateway to enforce restrictions on geographically bound calling plans.
Positioning calculationEdit
Main article: GNSS positioning calculation
See alsoEdit
NotesEdit
- ^ Orbital periods and speeds are calculated using the relations 4π²R³ = T²GM and V²R = GM, where R = radius of orbit in metres, T = orbital period in seconds, V = orbital speed in m/s, G = gravitational constant ≈ 6.673×10−11 Nm²/kg², M = mass of Earth ≈ 5.98×1024 kg.
- ^ Approximately 8.6 times (in radius and length) when the moon is nearest (363 104 km ÷ 42 164 km) to 9.6 times when the moon is farthest (405 696 km ÷ 42 164 km).
ReferencesEdit
- ^ a b "Beidou satellite navigation system to cover whole world in 2020". Eng.chinamil.com.cn. Retrieved 2011-12-30.
- ^ a b "Galileo Assessment Pulls no Punches". SpaceNews.com. 2011-01-20. Retrieved 2011-12-30.
- ^ "A Beginner’s Guide to GNSS in Europe" (PDF). IFATCA. Retrieved 20 May 2015.
- ^ "Boost to Galileo sat-nav system". BBC News. 25 August 2006. Retrieved 2008-06-10.
- ^ "Commission awards major contracts to make Galileo operational early 2014". 2010-01-07. Retrieved 2010-04-19.
- ^ "GIOVE-A launch News". 2005-12-28. Retrieved 2015-01-16.
- ^ "GPS Space Segment". Retrieved 2015-07-24.
- ^ "GLONASS status". Retrieved 2015-07-24.
- ^ "India to develop its own version of GPS". Rediff.com. Retrieved 2011-12-30.
- ^ S. Anandan (2010-04-10). "Launch of first satellite for Indian Regional Navigation Satellite system next year". Beta.thehindu.com. Retrieved 2011-12-30.
- ^ "India to build a constellation of 7 navigation satellites by 2012". Livemint.com. 2007-09-05. Retrieved 2011-12-30.
- ^ The first satellite IRNSS-1A of the proposed constellation, developed at a cost of 16 billion (US$280 million),[3] was[4] launched on 1 July 2013 from Satish Dhawan Space Centre
- ^ "ISRO: All 7 IRNSS Satellites in Orbit by March". gpsworld.com. 2015-10-08. Retrieved 2015-11-12.
- ^ "India to have its own fully-functional GPS system by June 2016: ISRO".
- ^ "JAXA Quasi-Zenith Satellite System". JAXA. Retrieved 2009-02-22.
- ^ "DORIS information page". Jason.oceanobs.com. Retrieved 2011-12-30.
- ^ "Globalstar GSP-1700 manual" (PDF). Retrieved 2011-12-30.
- ^ [1] Archived November 9, 2005, at the Wayback Machine.
Further readingEdit
- Office for Outer Space Affairs of the United Nations (2010), Report on Current and Planned Global and Regional Navigation Satellite Systems and Satellite-based Augmentation Systems. [2]
External linksEdit
Information on specific GNSS systemsEdit
Edit
- United Nations International Committee on Global Navigation Satellite Systems (ICG)
- Institute of Navigation (ION) GNSS Meetings
- The International GNSS Service (IGS), formerly the International GPS Service
- International Global Navigation Satellite Systems Society Inc (IGNSS)
- International Earth Rotation and Reference Systems Service (IERS) International GNSS Service (IGS)
- US National Executive Committee for Space-Based Positioning, Navigation, and Timing
- US National Geodetic Survey Orbits for the Global Positioning System satellites in the Global Navigation Satellite System
- UNAVCO GNSS Modernization
- Asia-Pacific Economic Cooperation (APEC) GNSS Implementation Team
Supportive or illustrative sitesEdit
- GPS and GLONASS Simulation (Java applet) Simulation and graphical depiction of the motion of space vehicles, including DOP computation.
- GPS, GNSS, Geodesy and Navigation Concepts in depth
No comments:
Post a Comment