This document provides an introduction and overview of Glonass, the Russian global navigation satellite system. It discusses the history and development of Glonass, the system components including satellites and ground control segment, orbital characteristics, signals and navigation message, augmentation system for differential corrections, modernization plans, and examples of current and potential performance when using Glonass in combination with GPS.

1. Introduction to Glonass
Kees de Jong, Fugro Intersite B.V., Leidschendam
March 2009
www.fugro.com

2. Contents
Global’naya Navigatsionnaya Sputnikovaya Sistema
Global Navigation Satellite System
• History
• System
• Signals
• Augmentation
• Performance
www.fugro.com

3. History
• Development started by Soviet Union in 1960’s-1970’s
• Successor of Tsikada
• First launch 1982
• Full constellation (24 satellites) in 1996
Tsikada satellite
www.fugro.com

4. History
United States
• Development started by Soviet Union in 1960’s-1970’s
• Successor to Tsikada Transit
• First launch 1982 1978
• Full constellation (24 satellites) in 1996 1994
Transit
Tsikada satellite
www.fugro.com

5. Glonass system components
Ground control Orbit
Launchers
segment constellation
Spacecraft
Glonass Proton
control
Orbit
Glonass-M Soyuz
determination
Time
Glonass-K
synchronization
www.fugro.com

6. Ground control segment
SCC System Control Center
TT&C Telemetry, Tracking & Commanding station
ULS Uplink Station
MS Monitoring Station
CC Central Clock
SLR Satellite Laser Ranging station
www.fugro.com

7. Satellites
• Glonass (one operational satellite)
• Glonass-M (19 operational satellites)
• Glonass-K (from 2010 onwards)
Status March 2009
www.fugro.com

8. Satellite launches
• Recent
– September 2008
– December 2008
• Near future
– September 2009
– December 2009
Three satellites per launch
www.fugro.com

9. Constellation age
70
60
50
Age (months)
40
30
20
10
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Satellite
Glonass Glonass-M
Status March 2009
www.fugro.com

10. Satellite constellation
120° 120°
135° 6 14 22
- Not available
- Available
90° 7 15 23
45° 8 16 24
0° 1 9 17
315° 2 10 18
270° 3 11 19
225° 4 12 20
64.8° 64.8° 64.8°
180° 5 13 21
Latitude Plane I Plane II Plane III
Status March 2009
www.fugro.com

11. Orbital characteristics
System Glonass GPS
Number of satellites 24 30+
Number of orbital planes 3 6
Semi-major axis 25500 km 26550 km
Eccentricity < 0.01 < 0.01
Inclination 64.8° 55°
Period of revolution 11h16m 11h58m
Repeat period 8 days 1 day
www.fugro.com

12. Satellite orbits (1)
Glonass
Glonass GPS
GPS
North North
0 0
30 30
60 60
West East West East
90 60 30 0 90 60 30 0
South South
One satellite, eight consecutive days
www.fugro.com

13. Satellite orbits (2)
Glonass
Glonass
North
0
30
60
West East
90 60 30 0
South
Two adjacent satellites, three consecutive days
www.fugro.com

14. Signals – carriers
• Nominal carrier frequencies
– L1: 1602 MHz (GPS: 1575.42 MHz)
– L2: 1246 MHz (GPS: 1227.60 MHz)
• Satellite specific frequencies
– L1k = L1 + k×0.5625 MHz
k = -7…13
– L2k = L2 + k×0.4375 MHz
Note: L1k/ L2k = 9/7 for all k
www.fugro.com

15. GNSS spectrum
Glonass
Galileo
GPS
(L3) L2 L1
E5a E5b E6 E1
L5 L2 L1
Frequency (MHz)
16
15
12
12
11
12
12
02
75
78
46
76
27
07
.4
.7
.4
.6
.1
2
5
5
4
www.fugro.com

16. Signals – codes
Glonass GPS
C/A code
Frequency 0.511 MHz 1.023 MHz
Chip length 587 m 293 m
P-code
Frequency 5.11 MHz 10.23 MHz
Chip length 59 m 29 m
Modulation scheme FDMA CDMA
FDMA - Frequency Division Multiple Access (Glonass: same
code for all satellites, different frequencies)
CDMA - Code Division Multiple Access (GPS: different codes
for all satellites, same frequencies)
www.fugro.com

17. Signals – navigation message
Glonass GPS
Orbit Position, velocity, Keplerian elements
acceleration at and corrections
at reference time at reference time
Clock Clock offset and Clock offset, drift
drift at reference and drift rate at
time reference time
Update period 30 minutes Two hours
Almanac Keplerian elements Keplerian elements
www.fugro.com

18. Differential corrections and integrity
• SDCM
– System of Differential Correction and Monitoring
• Similar to
– WAAS (USA)
– EGNOS (Europe)
– MSAS (Japan)
– GAGAN (India)
www.fugro.com

19. SDCM – principle of operation
www.fugro.com

20. SDCM – characteristics
• Service area
– Russian Federation
• Real-time differential positioning
– Code
• Horizontal positioning accuracy 1-1.5 m
• Vertical positioning accuracy 2-3 m
– Carrier
• Horizontal positioning accuracy 0.01-0.02 m
• Vertical positioning accuracy 0.04-0.06 m
• GNSS monitoring
– Real-time integrity monitoring
– A posteriori system performance evaluation
• Two geostationary satellites
www.fugro.com

21. SDCM – reference stations
www.fugro.com

22. Modernization
• New (Glonass-K) satellites (from 2010 onwards)
• More satellites (30, probably not before 2015)
• Improved accuracy
• Modernized ground control segment
• New signals:
– L3 (1201-1212 MHz, to be defined
(Galileo E5b 1207.14 MHz))
– CDMA (on first Glonass-K
demonstration satellite in 2010)
• Interoperability with GPS and Galileo
Glonass-K satellite
www.fugro.com

23. Availability of signals
L1OF – L1 Open FDMA
L2OF – L2 Open FDMA
www.fugro.com

24. Recent accomplishments
• New geodetic datum
– Change from PZ90 to PZ90.02 in September 2007
– PZ90.02, differences with ITRS less than 0.5 m
• User range accuracy
– ICD 3.7 m
– Actual 1.8
• Clock stability
– 10-13 s/s
ICD – Interface Control Document
www.fugro.com

25. Example of current geometry
PDOP
www.fugro.com

26. GPS/Glonass reference stations
Fugro’s G2 network, 40+ GPS/Glonass reference stations
www.fugro.com

27. Fugro G2 GPS/Glonass positioning service
• Real-time GPS/Glonass orbit and clock corrections
– Accuracy better than 0.15 m
• Precise Point Positioning (PPP)
– Global accuracy 0.1 – 0.2 m
• Combined GPS/Glonass solution
– Improved reliability
– Increased availability
www.fugro.com

28. www.fugro.com
Number of satellites
0
5
10
15
20
25
0:00:00.0
1:00:00.0
2:00:00.0
3:00:00.0
4:00:00.0
5:00:00.0
6:00:00.0
7:00:00.0
8:00:00.0
9:00:00.0
10:00:00.0
11:00:00.0
GPS
12:00:00.0
13:00:00.0
14:00:00.0
Glonass
15:00:00.0
16:00:00.0
17:00:00.0
18:00:00.0
19:00:00.0
Delft, Netherlands, March 2009
20:00:00.0
21:00:00.0
22:00:00.0
23:00:00.0
Increased availability

29. Error (m)
-5
-4
-3
-2
-1
0
1
2
3
4
10:30:00.0 5
10:45:00.0
Z
Y
X
11:00:00.0
www.fugro.com
11:15:00.0
Clock
11:30:00.0
Satellite 2
11:45:00.0
12:00:00.0
-0.3
4.9
0.1
-2.4
12:15:00.0
12:30:00.0
Mean (m)
Clock
12:45:00.0
X
13:00:00.0
13:15:00.0
Y
5.8
1.4
3.6
3.0
13:30:00.0
Z
13:45:00.0
RMS (m)
14:00:00.0
14:15:00.0
14:30:00.0
Error (m) 14:45:00.0
-15
-12
-9
-6
-3
0
3
6
9
12
15
15:00:00.0
10:30:00.0
15:15:00.0
10:45:00.0
11:00:00.0
11:15:00.0
11:30:00.0
Z
Y
X
11:45:00.0
12:00:00.0
Clock
12:15:00.0
12:30:00.0
Clock
12:45:00.0
-3.1
0.9
-2.6
1.5
X
13:00:00.0
13:15:00.0
Mean (m)
Y
13:30:00.0
Z
13:45:00.0
14:00:00.0
1.6
0.7
0.7
0.5
14:15:00.0
RMS (m)
14:30:00.0
14:45:00.0
15:00:00.0
Broadcast clock and orbit errors
Satellite 24
15:15:00.0

30. G2 PPP GPS only
www.fugro.com

31. G2 PPP GPS and Glonass
www.fugro.com

32. G2 PPP Glonass only
www.fugro.com

33. Resources
• Russian Space Agency, status and ICD
– http://www.glonass-ianc.rsa.ru
• Trimble GPS/Glonass almanacs
– ftp://ftp.trimble.com/pub/eph/almanac.alm
• University of New Brunswick, constellation
– http://gge.unb.ca/Resources/GLONASSConstellationStatus.txt
• Wikipedia, general information
– http://en.wikipedia.org/wiki/Glonass
www.fugro.com