The document discusses the benefits of using GLONASS satellites in addition to GPS satellites. It notes that combining GPS and GLONASS provides more satellites which results in better positioning accuracy and reliability. Specifically, the addition of GLONASS leads to 15% better performance. It also discusses how hardware biases between different satellite systems must be accounted for in combined GPS/GLONASS processing. Finally, it promotes the Leica 1200+ system as being able to support current and future GNSS constellations like Galileo and Compass.

1. GLONASS: Wat brengt het ons?
Leica Geosystems b.v.
Jeroen Zomerdijk
Content
GLONASS benefits in position /
height improvement
Hardware Biases of GLONASS
System 1200+ GNSS
Corporate
Conclusions
2

2. GLONASS: Benefits
GLONASS: Benefits
General Characteristics – Availability Nov 2007
• 17 operating satellites
• At least 7 satellites GPS+GLONASS all the time with cut off 10°
• GPS only has minimum of 5 satellites needed for ambiguity fixing RTK
4

3. GLONASS: Benefits
Ambiguity Resolution Nov 2007
GPS only
At least 5 GPS satellites are necessary to get a high accuracy
(fixed) solution.
Combined GPS and GLONASS
At least 5 GPS or 4 GPS + 2 GLONASS satellites are necessary
to get a high accuracy (fixed) solution.
Benefit of GPS + GLONASS on a statistical basis (open sky
environment, urban canyons, tree environment, kinematic data,
long static baseline)
Approx. 15 % !
5
GLONASS: Benefits
Better Geometry Nov 2007
Example Vertical Dilution of Precession (VDOP)
• VDOP is indicator for achievable height accuracy. Large VDOP low
height accuracy
• GPS only VDOP goes up to 4
• Combined GPS/GLONASS: VDOP always below 2.5
6

4. GLONASS: Benefits
Height Accuracy with and without GLONASS Nov 2007
15km Baseline
474.5
GPS
474.45 GPS+GLONASS
Height [m]
474.4
474.35
474.3
474.25
10 10.5 11 11.5 12 12.5 13 13.5 14
Time [h]
14
12
10
# Sats
8
6
4
10 10.5 11 11.5 12 12.5 13 13.5 14
Time [h]
7
GLONASS: Benefits
Ambiguity Resolution
Percentage Ambiguity-Resolution
(continuous re-initialisation)
Project BL Length (m) GPS [%] GPS/GLONASS [%]
IGS Stations 149,152 53.31 61.76
Train 30 55.89 90.49
Tree 19,874 72.73 100
Static 2,053 97.06 99.22
8

5. GLONASS: Benefits
General Characteristics – Availability Now
• Currently 20 operating satellites (March 27, 2009)
• At least 12 satellites GPS+GLONASS all the time with cut off 10°
• GPS only has minimum of 7 satellites
9
GLONASS Benefits
Summary
• Larger number of satellites yields higher
accuracy
• GLONASS stabilizes GPS geometry => higher
accuracy
• Combined GPS/GLONASS more satellites
available for reliable ambiguity fixing in RTK
• Performance enhancement about 15%
compared to GPS only operation

6. Interoperability of GLONASS observations for RTK
positioning applications
Content
Hardware Biases
Impact on RTK Applications
Elimination of Hardware Biases
Conclusion
12

7. GLONASS
History
1982: Launch of 1st satellite
1995: Full Constellation
End of 90s:
Financial problems
Problems with satellite lifetime
2001: Only 7 satellites available
Since 2006: Financing secured
Since 2007: Number of yearly
satellite launches increased to 6
13
Combined GPS/GLONASS Processing
Advantages
More satellites available
Better geometry
Result
More fixed epochs
Higher Accuracy, reliability
But …
14

8. GNSS Observations
Hardware Biases Satellite p
Pm = ρ m − cδtm + cδt p + ε m
p p p
Noise
Satellite clock error
Distance ρ
Antenna electronics
Receiver clock error
True distance Station m
Antenna cable Receiver electronics
Measurement
15
GNSS Observations
Hardware Biases
Pm = ρ m − cδtm + cδt p + cH m + ε m
p p p p
Hardware Bias
Antenna electronics
Antenna cable Receiver electronics
16

9. GNSS Observations
Zero, Single and Double Differences
Zero Difference
Pm = ρ m − cδt m + cδt p + cH m + ε m
p p p p
17
GNSS Observations
Zero, Single and Double Differences
Zero Difference
Pm = ρ m − cδt m + cδt p + cH m + ε m
p p p p
Single Difference
Satellite clock error is eliminated
p p p p
Pm,n = ρ m,n − cδtm,n + cH m,n + ε m,n
m n
18

10. GNSS Observations
Zero, Single and Double Differences
Zero Difference
Pm = ρ m − cδt m + cδt p + cH m + ε m
p p p p
Single Difference
Satellite clock error is eliminated
p p p p
Pm,n = ρ m,n − cδtm,n + cH m,n + ε m,n
Double Difference m n
Receiver clock error is eliminated, Hardware bias remains
Pmpq ,i = ρ m ,n + cH m ,n ,i + ε m ,n ,i
,n
pq pq pq
p q
19
Hardware Biases
Frequency Dependency
GPS
All satellites send different code on identical frequencies (CDMA)
Same hardware bias for all satellites f p = f q = f GPS ⇒ H p = Hq
GLONASS
All satellites send identical code on different frequencies (FDMA)
Different hardware bias for each satellite f GPS ≠ f GLO ⇒ H GPS ≠ H GLO
PSD of L1 code f GLO , p ≠ f GLO ,q ⇒ H GLO , p ≠ H GLO ,q
20
Frequency [MHz]

11. Impact of Hardware Biases
Example: Zero-Baseline, DD Code
DD Code residuals [m]
Time [h]
21
Impact of Hardware Biases
Example: Relative Measurements to 2 Satellites
p q
Station m
Different Hardware Bias for satellite p and q
Station n
Different Hardware Bias for satellite p and q
Station m and n
Identical Hardware Biases for all satellites if identical
m n
hardware!
22

12. Impact of Hardware Biases
Example: Identical Hardware
p
p p p
H m = H n ⇒ H m ,n = 0
23
m n
Impact of Hardware Biases
Identical Hardware, Zero Baseline, DD Code
Identical Hardware
DD Code residuals [m]
Time [h]
24

13. Impact of Hardware Biases
Identical Hardware, Zero Baseline, DD Code
Mixed Hardware
DD Code residuals [m]
Time [h]
25
Impact of Hardware Biases
Zero Baseline, DD Phase Observations
Mixed Hardware Identical Hardware
DD Phase residuals [m]
DD Phase residuals [m]
Time [h] Time [h]
26

14. GLONASS Biases
Calibration and Correction in Real Time
Preface
Reference receiver type transmitted in various correction formats like RTCM 3
Implementation
Rover detects reference receiver type and corrects reference observations in real
time
Alternatively: reference receiver type is set manually on the rover. Again the rover
corrects reference observations in real time
since version 7.0
27
GLONASS Biases
Real Time Correction
Mixed Hardware Mixed Hardware Identical Hardware
DD Phase residuals [m]
Time [h] Time [h] Time [h]
28

15. GLONASS Benefits
Summary
• RTK users profits via RTCM format of
elimination of GLONASS hardware biases
• Improvement of quality
• Benefit for mixed hardware for rover users
System 1200+ GNSS

16. Leica, GNSS Surveying and Future Satellite Signals
Surveying with GNSS in 2016 …
2008 2015
• 31 GPS and 16 Glonass • 32 GPS, 24 Glonass, 30 Galileo +
Compass
• 2 Frequencies (L1, L2) • 3 Frequencies (L1, L2, L5)
• 26 observations per epoch on • >80 observations per epoch on
average in open sky average in open sky
• 12 observations per epoch with • ~30 observations per epoch with
obstruction obstruction
• RTK up to 30km • RTK up to 50km
• 8“ typical initialisation time • 1“ typical initialisation time
• RTK accuracy ±15mm • RTK accuracy ±10mm
31
GPS L5, Galileo, Compass and Leica System
....before L5 will be up there
...fully capable of GPS, GLONASS, Galileo and Compass!!
32

17. GPS1200+ THE ONLY FUTURE PROOF GNSS
Properties Future Proof Most Accurate Most Flexible
Features • GPS L1, L2 (C/P) • SmartRTK+ Technology • Single Base
(Highest Consistencyin Networks)
• GPS L5 • Full Network Rover
• RTCM 3.1 correction
• GLONASS • Open Interface OWI
• SmartCheck+ Technology
• Galileo • Partner–Software on Board
(Continuous Ambiguitycheck)
• Galileo–AltBOC signal • Backpack Solution
• SmartTrack+ Technology
• Compass (Robust Signaltracking) • All-on-Pole
• SmartPole • SmartWorx
• SmartStation
Advantage Investment holds its value
Benefit Customer saves money
33
Leica Geosystems
- when it has to be right
Corporate

18. From space to nano technology
Measuring Precision
< 10.000 km < 10 Meters < 100 µm < 20 µm < 0,3 µm
Reach
Space Macro Micro Nano
Technology - GPS/GNSS - Laser Scan - 3D Tactile - Light
- Laser Scan - Laser Track - 2.5D Vision - Micro Optics
- Laser Track - Laser Radar
- Laser Radar - Photogram
- Optics - Optics
- Photogram - Tactile
- PS
35
Today’s technologies
for fast, efficient data capture
One Millions of Image-based
point points
TPS Aircraft-based
Laser Scanning
GPS Remote sensing
Point-cloud Management
Photo-
DISTOTM grammetry
36

19. We measure our success by yours:
customers define the world we live in
Building the tallest bridge in the world
With pylons reaching 343 meters (1,115
feet) in height, the Viaduct de Millau near
Montpellier in southern France is the
tallest bridge in the world – 19 meters
(62 feet) taller than the Eiffel Tower.
Leica Geosystems TotalStations with
integrated GPS positioning were used in its
construction, and for the continuous post-
construction monitoring of this record-
breaking structure.
37
We measure our success by yours:
customers define the world we live in
The “Eighth Wonder of the World” gives up
its secret
For 1500 years, the Hagia Sofia in Istanbul
has confounded expert analysis of its
design. Its enormous dome is 56 meters
(184 feet) high and 34 (111 feet) meters
wide, supported on just four pillars.
Now, Leica Geosystems high definition laser
surveying equipment has revealed the elegant
and ingenious design behind the structure’s
astonishing stability.
38

20. We measure our success by yours:
customers define the world we live in
Monitoring Burj Dubai, tallest building in
the world
Leica Geosystems’ solutions deliver
accurate positioning data for construction
set out at the top level of the formwork
Leica Geosystems Instruments and
Software:
Network of Leica NIVEL220
Leica GRX1200 Pro Reference Stations
Leica GX1220 as Rover equipment
Leica TPS1205
Leica GPS Spider and GNSS QC software
Leica Geo Office processing software
39
Leica Geosystems:
Technologies for every workflow
40

21. Pioneer and market leader
with the most comprehensive range of solutions
Surveying
Civil engineering
Monitoring
Construction
Machine control
Mobile mapping
Mining and extraction
Real estate
Agriculture, forestry and
land management
Industrial solutions
….
41
Leica Geosystems Benefits
Conclusions
• Larger number of satellites yields higher
accuracy. -> even more valid with full GNSS
systems; GPS L5, Glonass, Galileo and
Compass.
• Hardware biases correctly handled between
different satellite systems or receiver types
• 1200+ receivers tracks all these GNSS satellite
systems, now and future
• Leica Geosystems dedicated global company
for broad range of precise measurements, all
types of solutions and workflows.