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==GLONASS Availability== | ==GLONASS Availability== | ||
[[File:GLONASSavailability.jpg|Integral availability of GLONASS navigation (PDOP≤6) during the 24 hours period (mask angle ≥5 deg) Date: 25.04.2011|300px|thumb|right]] | |||
At the moment of this publication (April 2011) there are 27 GLONASS satellites in orbit although only 23 of them are operational. Availability performance (calculated as the percentage of time during which the condition PDOP ≤ 6 is valid at mask angles ≥ 5 deg) obtained with the current constellation is shown in the right figure. | At the moment of this publication (April 2011) there are 27 GLONASS satellites in orbit although only 23 of them are operational. Availability performance (calculated as the percentage of time during which the condition PDOP ≤ 6 is valid at mask angles ≥ 5 deg) obtained with the current constellation is shown in the right figure. | ||
{| class="wikitable" | {| class="wikitable" | ||
!rowspan="1"|Date | !rowspan="1"|Date | ||
Revision as of 13:17, 7 July 2011
| GLONASS | |
|---|---|
| Title | GLONASS Performances |
| Author(s) | GMV |
| Level | Basic |
| Year of Publication | 2011 |
One of the main objectives of the Global Navigation System (GNS) is to ensure GLONASS performance similar to GPS by the end of 2011. GLONASS traditional poorer performance was the culmination of several factors:[1]
- poorer on-board atomic clocks
- less stability and predictability in the satellite orbits (and therefore less accuracy in GLONASS broadcast ephemerides)
- fewer satellites providing signals
- operational control and ground monitoring segment limited to Russian territory.
The improvements carried out on the space, ground-based and user equipment segments have paid off, increasing the accuracy of GLONASS by 5 times in the last years[2] and providing 100% availability in the Russia territorry and practically global coverage.
GLONASS Availability
At the moment of this publication (April 2011) there are 27 GLONASS satellites in orbit although only 23 of them are operational. Availability performance (calculated as the percentage of time during which the condition PDOP ≤ 6 is valid at mask angles ≥ 5 deg) obtained with the current constellation is shown in the right figure.
| Date | Operational Satellites in constellation | Integral Availability Global | Integral Availability on Russian territory |
|---|---|---|---|
| 2011/07/06 | 23 | 99.5 % | 100 % |
| 2011/01/01 | 22 | 99 % | 100 % |
| 2010/01/01 | 15 | 73.6 % | 85.3 % |
| 2009/01/01 | 16 | 87.4 % | 96.6 % |
| 2008/01/01 | 12 | 48 % | 57.6 % |
| 2007/01/01 | 9 | 19.2 % | 26.3 % |
GLONASS accuracy
According to Revnivykh,[2] deputy director of the Russian space agency’s Mission Control Cente, GLONASS accuracy has five times improved in the last years. As it is shown in the figure on the right, in 2006 GLONASS Signal In Space Range Error (SISRE) at 1 sigma was in the order of 25 m. At the moment of this publication, July 2011, the accuracy of GLONASS is 6-7 metres, the same order as GPS.
As Anatoly Shilov said at the 5th international forum on satellite navigation yesterday, the accuracy of the Russian navigation system would have to be improved to 2-3 metres in the following years.