GLONASS
What is GLONASS?
- GLONASS is the acronym for the Global Navigation Satellite System operated for the Russian government by the Russian Aerospace Defense Forces.
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GLONASS provides the only alternative to the United States Global Positioning System offering global coverage and comparable precision.
GLONASS Operation
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GLONASS is a global satellite navigation system, providing real time position and velocity determination for military and civilian users.
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GLONASS satellites transmit two types of signals; A standard precision (SP) signal and an obfuscated
high precision (HP) signal.
- L1 Signal: 1598.0625 - 1609.3125 MHz
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At peak efficiency, the SP signal offers:
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Horizontal positioning accuracy within 5–10 meters
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Vertical positioning within 15 meters
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A
velocity vector measuring within 10 cm/s.
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The more accurate HP signal is only available for authorized users, such as the Russian military.
GLONASS Coverage
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The constellation operates in three orbital planes, with 8 evenly spaced satellites on each.
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Satellites orbit at
11,868 miles (19,100 km) altitude with a 64.8 degree inclination and a period of 11 hours and 15 minutes.
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GLONASS' orbit makes it especially suited for usage in high latitudes (north or south), where getting a GPS
signal can be problematic.
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A fully operational constellation with global coverage consists of 24 satellites, while 18 satellites are necessary for covering the territory of Russia.
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To get a position fix, the receiver must be in the range of at least four satellites, three of which will be used to determine the user's location and the fourth to synchronize clocks of the receiver and the three other spacecraft.
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Current
GLONASS constellation configuration identified by Slot Number:
Slot |
NMEA |
|
Slot |
NMEA |
|
Slot |
NMEA |
1 |
65 |
9 |
73 |
17 |
81 |
2 |
66 |
10 |
74 |
18 |
82 |
3 |
67 |
11 |
75 |
19 |
83 |
4 |
68 |
12 |
76 |
20 |
84 |
5 |
69 |
13 |
77 |
21 |
85 |
6 |
70 |
14 |
78 |
22 |
86 |
7 |
71 |
15 |
79 |
23 |
87 |
8 |
72 |
16 |
80 |
24 |
88 |
GLONASS Availability
Do I Need GLONASS?
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Many modern
GPS receivers (GPSr) are able to use both GLONASS and GPS satellites simultaneously.
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GPS + GLONASS can provide improved coverage and quicker time to fix due to
having twice as many satellites available.
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For indoor, urban, canyon or mountainous areas, accuracy can be improved over using GPS alone.