GLONASS
GLONASS (Russian ГЛОНАСС, as an acronym for Глобальная навигационная спутниковая система (Global Nawigazionnaja Sputnikowaja sistema ), " Global Navigation Satellite System") is a global navigation satellite system that is operated and funded by the Ministry of Defence of the Russian Federation.
History
GLONASS is similar in structure and operation to the U.S. NAVSTAR GPS. The satellites of the GLONASS constellation bear the name Uragan ( Hurricane ). Technically GLONASS is based on similar principles as GPS. The parallel, independent development of the two equivalent systems during the Cold War was of strategic military reasons.
The development of the system began in 1972. The first three satellites launched on 12 October 1982 the system has been officially declared on 24 September 1993 as operational. The maximum configuration, consisting of 21 standard and three spare satellites was achieved in 1996. In subsequent years, the number of functioning satellites but went back dramatically so that GLONASS was not usable as a standalone navigation system.
On 12 September 2008 ordered the prime minister of Russia, Vladimir Putin, the re- completion of GLONASS for 67 billion rubles ( 1.8 billion euros ) to the year 2012. Despite the false starts a launcher on December 5, 2010, in which were lost three satellites, was again from 2011 a full GLONASS system. On July 2, 2013, came again to a crash of a Proton-M rocket, which in turn three GLONASS satellites were destroyed.
In July 2010, announced Vladimir Yevtushenkov, head of responsible for GLONASS Group Sistema, that Russia ban imports of mobile phones planning that are not equipped with the system.
Technology
The satellites orbit the earth on a medium Earth orbit in three orbital planes with 64.8 ° inclination to the equator (GPS 55 °). This reach the satellites for users in high geographical latitudes, especially in the polar regions, a greater height, so that the availability of the system is improved over the horizon. The semi-major axis of the orbit is 25,500 km, the orbital altitude 19,100 km ( 20,200 km GPS ). The turn around time is 11:15 h (GPS 11:58 ).
In contrast to the GPS with GLONASS satellites transmit all with the same code ( pseudo-random noise, PRN for English pseudo- random noise), but at different frequencies ( FDMA) in the decimeter range. Send antipodal satellites with the same channel number and thus identical frequencies. Each satellite used by GLONASS transmits signals on two frequencies:
- L1 = 1602 MHz k · 562.5 kHz
- L2 = 1246 MHz k · 437.5 kHz, where k denotes the channel number
When all GPS satellites use the same frequencies and are using code division multiple access ( CDMA) and inserted therein distinguished Gold sequences. CDMA is based in GLONASS, unlike GPS, on Kasami sequences and is used from the GLONASS -K satellite generation.
How GPS GLONASS required for normal operation nearly 24 satellites, so can be guaranteed that always at least four of which are visible in one place. By 2011, the number of operational satellites for enough not always, so that enough satellites were available for the determination of position is not always at every location on the Earth's surface. With a known location then only a determination of time is possible. If three satellites are visible, three parameters can be derived from the signals, eg by known height ( ship at sea ) the place (geographic latitude and geog. Length ) and time. To the time, relatively high demands are made on the accuracy, as a timing error of one microsecond already leads to a location error of the order of 300 meters. Mobile receiver therefore need the exact time, a fourth satellite signals are required for their determination for a full localization ( latitude, longitude, altitude above sea level) as the fourth parameter.
System Architecture
Satellite constellation ( space segment )
The first Uragan test satellite Cosmos 1413 was launched in October 1982 along with two Uragan dummies in its orbit. Originally, the system should include 21 satellites for normal operation and three spare satellites. The new plan provides for 30 satellites, which are spread over three orbits of eight satellites each, and two spare satellites.
After the collapse of the Soviet Union were to the year 1995, more satellites will be launched, which had been well completed even during Soviet times, so that in 1995 had a system of 25 satellites functioning. In 1998 the number was, however, already dropped to 13 and decreased to 2001 only seven satellites. As of 2002, the number of functioning satellites began to rise again. The problem was the high failure rate due to the very short lifetime of the individual Uragan satellites of only three years.
Since 2001 also improved Uragan -M satellites will be used with a service life of seven years. The new generation of lower -off mass and a lifetime of ten years is called Uragan - K; the first launch took place on February 26, 2011. Uragan and Uragan -M (both 1415 kg ) are often started in a triple with heavy Proton rockets, but sometimes also as the lighter Uragan - K with a significantly lower Sojus-2/Fregat.
The end of 2005 three more GLONASS satellites (two Uragan -M and a Uragan ) were launched by a Proton rocket, the end of 2006 was followed by another proton - start with three Uragan - M satellite; in October 2007, December 2007, September 2008, December 2008, December 2009, March 2010 and September 2010, three satellites were launched. Three satellites you had a false start in December 2010 lost three more in early July 2013.
The start date refers to the Coordinated Universal Time ( UTC), the commissioning of the Moscow time zone.
Ground stations
Ground stations, called the Control segment, are located in Moscow ( Krasnoznamensk and Schtscholkowo ), in Komsomolsk -on-Amur, near St. Petersburg, in Yenisejsk (all on the territory of the Russian Federation ) and in Ternopil (Ukraine).
User segment (user segment)
In 2008 there were the first civilian commercially used devices that support GLONASS. The system is thus in direct competition with the American GPS, the European Galileo system and China's Beidou.
Specially designed navigation devices can obtain data from both the GLONASS as well as receive GPS satellite signals and by evaluating both better coverage. Even when a system fails, or as protection against manipulation ( see GPS Jammer ) this application has advantages.
In 2009, the first Russian fully integrated on a single chip receiver for GLONASS (including GPS / Galileo / Compass ) has been presented. In April 2011, ZTE launched the first smartphone on the market that uses GPS and GLONASS in addition, this was followed by several smart phones from different manufacturers.
Extensions
To improve the accuracy, especially by correcting the varying influences of the ionosphere on the signal propagation times, with SDCM for GLONASS Satellite Based Augmentation System in a building.
The ERA GLONASS project (Russian экстренного реагирования при авариях, extrennowo reagirowanija pri awarijach; German emergency response in case of accidents ) provides for devices which automatically settle in traffic accidents, an alarm message, which also contains the site. The system will be compatible with the European eCall.