Jeroen Zomerdijk
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Transcript of Jeroen Zomerdijk
GLONASS: Wat brengt het ons?
Leica Geosystems b.v.Jeroen Zomerdijk
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Content
� GLONASS benefits in position /
height improvement
� Hardware Biases of GLONASS
� System 1200+ GNSS
� Corporate
� Conclusions
GLONASS: Benefits
4
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
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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 % !
GLONASS: Benefits
Ambiguity Resolution Nov 2007
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GLONASS: Benefits
Better Geometry Nov 2007Example 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
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10 10.5 11 11.5 12 12.5 13 13.5 14474.25
474.3
474.35
474.4
474.45
474.5
Time [h]
Height [m
]
15km Baseline
GPS
GPS+GLONASS
10 10.5 11 11.5 12 12.5 13 13.5 144
6
8
10
12
14
Time [h]
# Sats
GLONASS: BenefitsHeight Accuracy with and without GLONASS Nov 2007
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� 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
GLONASS: Benefits
Ambiguity Resolution
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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
• 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
GLONASS Benefits
Summary
Interoperability of GLONASS observations for RTK
positioning applications
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Content
� Hardware Biases
� Impact on RTK Applications
� Elimination of Hardware Biases
� Conclusion
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� 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
GLONASS
History
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Combined GPS/GLONASS Processing
Advantages
� More satellites available
� Better geometry
� Result
� More fixed epochs
� Higher Accuracy, reliability
But …
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Antenna electronics
Receiver electronicsAntenna cable
GNSS Observations
Hardware Biases
pm
pm
pm
pm tctcP εδδρ ++−=
Measurement
True distance
Receiver clock error
Satellite clock error
Noise
Satellite p
Station m
Distance ρ
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Antenna electronics
Receiver electronicsAntenna cable
Hardware Bias
pm
pm
pm
pm
pm cHtctcP εδδρ +++−=
GNSS Observations
Hardware Biases
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Zero Difference
pm
pm
pm
pm
pm cHtctcP εδδρ +++−=
GNSS Observations
Zero, Single and Double Differences
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Zero Difference
Single Difference
� Satellite clock error is eliminated
pm
pm
pm
pm
pm cHtctcP εδδρ +++−=
pnm
pnmnm
pnm
pnm cHtcP ,,,,, εδρ ++−=
m n
GNSS Observations
Zero, Single and Double Differences
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Zero Difference
Single Difference
� Satellite clock error is eliminated
Double Difference
� Receiver clock error is eliminated, Hardware bias remains
pm
pm
pm
pm
pm cHtctcP εδδρ +++−=
pnm
pnmnm
pnm
pnm cHtcP ,,,,, εδρ ++−=
pq
inm
pq
inm
pq
nm
pq
inm cHP,,,,,,,
ερ ++=
m n
p q
GNSS Observations
Zero, Single and Double Differences
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Hardware Biases
Frequency DependencyGPS
� All satellites send different code on identical frequencies (CDMA)
� Same hardware bias for all satellites
GLONASS
� All satellites send identical code on different frequencies (FDMA)
� Different hardware bias for each satelliteGLOGPS
GLOGPS HHff ≠⇒≠
qGLOpGLOqGLOpGLO HHff
,,,, ≠⇒≠
qpGPSqp HHfff =⇒==
PSD of L1 code
Frequency [MHz]
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Impact of Hardware Biases
Example: Zero-Baseline, DD Code
Time [h]
DD Code residuals [m]
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Impact of Hardware Biases
Example: Relative Measurements to 2 Satellites
Station m
� Different Hardware Bias for satellite p and q
Station n
� Different Hardware Bias for satellite p and q
m n
p q
Station m and n
� Identical Hardware Biases for all satellites if identical
hardware!
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0, =⇒= pnm
pn
pm HHH
m n
p
Impact of Hardware Biases
Example: Identical Hardware
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Time [h]
DD Code residuals [m]
Impact of Hardware Biases
Identical Hardware, Zero Baseline, DD Code
Identical Hardware
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Time [h]
DD Code residuals [m]
Impact of Hardware Biases
Identical Hardware, Zero Baseline, DD Code
Mixed Hardware
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Time [h]
DD Phase residuals [m]
Time [h]
DD Phase residuals [m]
Impact of Hardware Biases
Zero Baseline, DD Phase Observations
Mixed Hardware Identical Hardware
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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
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GLONASS Biases
Real Time Correction
Time [h]Time [h]
DD Phase residuals [m]
Mixed Hardware Identical Hardware
Time [h]
Mixed Hardware
• RTK users profits via RTCM format of
elimination of GLONASS hardware biases
• Improvement of quality
• Benefit for mixed hardware for rover users
GLONASS Benefits
Summary
System 1200+ GNSS
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2008 2015
Leica, GNSS Surveying and Future Satellite Signals
Surveying with GNSS in 2016 …
• 31 GPS and 16 Glonass
• 2 Frequencies (L1, L2)
• 26 observations per epoch on
average in open sky
• 12 observations per epoch with
obstruction
• RTK up to 30km
• 8“ typical initialisation time
• RTK accuracy ±15mm
• 32 GPS, 24 Glonass, 30 Galileo +
Compass
• 3 Frequencies (L1, L2, L5)
• >80 observations per epoch on
average in open sky
• ~30 observations per epoch with
obstruction
• RTK up to 50km
• 1“ typical initialisation time
• RTK accuracy ±10mm
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GPS L5, Galileo, Compass and Leica System....before L5 will be up there
...fully capable of GPS, GLONASS, Galileo and Compass!!
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Future Proof Most Accurate Most FlexibleProperties
• GPS L1, L2 (C/P)
• GPS L5
• GLONASS
• Galileo
• Galileo–AltBOC signal
• Compass
• Single Base
• Full Network Rover
• Open Interface OWI
• Partner–Software on Board
• Backpack Solution
• All-on-Pole
• SmartWorx
• SmartRTK+ Technology
(Highest Consistencyin Networks)
• RTCM 3.1 correction
• SmartCheck+ Technology
(Continuous Ambiguitycheck)
• SmartTrack+ Technology
(Robust Signaltracking)
• SmartPole
• SmartStation
Features
Investment holds its valueAdvantage
GPS1200+ THE ONLY FUTURE PROOF GNSS
Customer saves moneyBenefit
Leica Geosystems
- when it has to be right
Corporate
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From space to nano technology
Technology
Space Macro Micro Nano
< 100 µm < 0,3 µm< 10 Meters < 20 µm
- GPS/GNSS- Laser Scan- Laser Track- Laser Radar- Optics- Photogram
- Laser Scan- Laser Track- Laser Radar- Photogram- Optics- Tactile- PS
- 3D Tactile- 2.5D Vision
- Light- Micro Optics
< 10.000 km
Reach
Measuring Precision
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� One
point
Today’s technologies for fast, efficient data capture
� Image-based
TPS
GPS
DISTOTM
Laser Scanning
Point-cloud Management
Aircraft-based
Remote sensing
Photo-grammetry
� Millions of
points
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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.
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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.
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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
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Leica Geosystems:
Technologies for every workflow
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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 andland management
� Industrial solutions
� ….
• 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.
Leica Geosystems Benefits
Conclusions