Transcript Applications of the real-time Swiss permanent GPS network 'AGNES' E. Brockmann, S.

Applications of the real-time Swiss
permanent GPS network 'AGNES'
E. Brockmann, S. Grünig, R. Hug, D. Schneider,
A.Wiget and U. Wild
[email protected]
www.swisstopo.ch
EGS Nice, April 2002
E. Brockmann
AGNES net
Geodynamics
GPS meteo
Positioning
Conclusions
Contents
• AGNES network
– History
– Stations
– Concept
• Applications
–
–
–
–
Surveying
Geodynamics
Meteorology
Positioning
• Conclusions
EGS Nice, April 2002
E. Brockmann
AGNES net
History
• 1989-1992: GPS based first order network (104 sites)
Accuracy:
0.5 - 1.0 cm horizontally
2.0 - 3.0 cm vertically
• 1995: Definition of CHTRS95 (equal ETRS89 at epoch
1993.0)
Conclusions
Positioning
GPS meteo
Geodynamics
April 2002
0 km
20 km
40 km
60 km
80 km
Swiss first
order network
(1989-1992)
100 km
EGS Nice, April 2002
E. Brockmann
• 1998: re-measuring of LV95 (CHTRF98); differences below
< 1 cm horizontally and < 3 cm vertically
AGNES net
Conclusions
Positioning
GPS meteo
Geodynamics
History (2)
• 1998: Start of the project with 8 permanent stations
• 2001: Completion with 29 permanent stations
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E. Brockmann
Conclusions
Positioning
GPS meteo
Geodynamics
AGNES net
AGNES stations
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E. Brockmann
AGNES net
Density of 50 km
29 stations
Positioning
GPS meteo
Geodynamics
AGNES network
Applications
Conclusions
• Positioning
• Reference frame
• Scientific
– GPS meteo
– Geodynamics
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E. Brockmann
AGNES net
AGNESStation 2
AGNESStation ...
AGNESStation 1
Federal Net
AGNESStation 21
KOMBV
“Daily
/hourly”
“Second”
LAN BIT
LAN SWISSTOPO
PNAC
Monitor
computer
Scientific
Applications
• Reference frame
• Geodynamics
• GPS meteo
Firewall
Communication
computer
Real-time
Positioning
Access
server
GSM
EGS Nice, April 2002
WWW server
Internet
Post-Proc.
Positioning
Public Net
Geodynamics
GPS meteo
Positioning
Conclusions
AGNES network (2)
E. Brockmann
AGNES net
Geodynamics
GPS meteo
• Trimble 4000SSi, Trimble 4700 and Leica System 530
receivers
• Different antenna types (Choke Ring, Microcentered
L1/L2, Zephyr), no radomes
• Individual antenna
calibration
(relative to “Choke”
Ring and “Geodetic”
antenna)
Conclusions
Positioning
AGNES GPS equipment
EGS Nice, April 2002
E. Brockmann
AGNES net
Geodynamics
• Advantages:
– Fewer neighboring sites to be measured (only 1 control site instead
of 3 neighboring sites)
– Better integration due to time series of the reference stations
Conclusions
Positioning
• First order network and densification campaigns are
integrated in the permanent network
GPS meteo
Surveying
EGS Nice, April 2002
E. Brockmann
AGNES net
Geodynamics
Conclusions
Positioning
GPS meteo
Surveying
CHTRF 98
CHTRF 98 Teil 1
CHTRF 98 Teil 2
CHTRF 98 Teil 3
LHN95 Emmental
LHN95 Sustenpass
Bern 99
Luzern 99
Saas Fee 99
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AGNES net
Geodynamics
• Permanent Network Analysis Center (PNAC) at the Swiss Federal
Office of Topography (swisstopo)
• Automated processing of all AGNES stations + 19 European tracking
stations (contribution to EUREF and reference frame maintenance in
Switzerland)
EUREF
EUREF
+
AGNES
Conclusions
Positioning
GPS meteo
Geodynamics
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E. Brockmann
AGNES net
Geodynamics
GPS meteo
http://www.swisstopo.ch/geoaktuell/en/pnac.htm
• Results updated daily /
weekly :
– Coordinates/Covariance
(SINEX format)
– Troposphere
parameters (SINEX
format)
– Time series, velocity
fields
Conclusions
Positioning
PNAC products
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AGNES net
Geodynamics
Time series: Zimmerwald (ZIMM)
Conclusions
Positioning
GPS meteo
2 cm
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E. Brockmann
Earthquake in Northern Italy, July 15, 2001 15:06 UTC, Magnitude: 4.8
?
2 cm
Antenna change
Conclusions
Positioning
GPS meteo
Geodynamics
AGNES net
Time series: Bolzano (BZRG)
EGS Nice, April 2002
E. Brockmann
AGNES net
Geodynamics
Time series: Samedan (SAME)
Positioning
GPS meteo
2 cm
?
Conclusions
?
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AGNES net
Conclusions
Positioning
GPS meteo
Geodynamics
Velocity field in ITRF00 (rel. ZIMM)
Velocities
for sites
with time
series
> 0.5 years
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E. Brockmann
• Collaboration of BKG, OLG, CNRS, IGN, UPAD, LPT for deriving a
dense Alpine dynamic model
AGNES net
Conclusions
Positioning
GPS meteo
Geodynamics
Alpine network
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E. Brockmann
AGNES net
Geodynamics
GPS meteo
L2 North
Microcentered
antenna
(w.r.t IGS values)
Conclusions
Positioning
Excursion: Antenna calibrations
EGS Nice, April 2002
E. Brockmann
AGNES net
Geodynamics
Microcentered
antenna
Conclusions
Positioning
Elev.-dep.
corrections
GPS meteo
Antenna calibrations (2)
EGS Nice, April 2002
E. Brockmann
AGNES net
Geodynamics
Impact of individual antenna models
Zimm:
Choke
Ring
STAB:
Zephyr
GPS meteo
2.5 mm Up
2.5 1.5
mmmm
EastEast
Positioning
-1.0 mm North
-0.5 mm North
Conclusions
-8.0 mm Up
EGS Nice, April 2002
E. Brockmann
AGNES net
Geodynamics
GPS meteo
• Partners in Switzerland:
– MeteoSwiss
– University of Berne (IAP)
– Swiss Federal Institute of Technology (ETH) Zurich
– COST 716:
Exploitation of ground-based GPS for climate and numerical
weather prediction applications
Conclusions
Positioning
GPS meteorology
EGS Nice, April 2002
E. Brockmann
AGNES net
Geodynamics
• Since Dec. 2001
• 50 sites:
– 21 EUREF
– 29 AGNES
• Near real-time results of 6
centers at KNMI:
http://www.knmi.nl/samenw/
cost716/
Conclusions
Positioning
GPS meteo
Hourly processing
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Integrated water vapor field (Sep. 10, 2001; 15:00 UTC)
Without GPS
GPS assimilated
Difference
AGNES net
Conclusions
Positioning
GPS meteo
Geodynamics
Numerical weather prediction tests
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AGNES net
Coordinate validation in NRT
24-hour average...
GPS meteo
Geodynamics
hourly ...
Conclusions
Positioning
± 1 cm
ZIMM
repeatability
in [mm]
hourly...
7 24-hours ø
[150 weeks]
North
16.0
1.0
0.9
East
45.0
4.6
0.8
Up
52.0
5.1
2.5
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E. Brockmann
AGNES net
Geodynamics
GPS meteo
• Establishing hourly processing as an operational service
(within COST 716)
• Routine validation (comparison of Swiss LM from weather
prediction with GPS)
• More assimilation tests
• Quality check of “real” real-time estimates (ZTD estimates
from RTK positioning) every 10 minutes
Conclusions
Positioning
Next steps
EGS Nice, April 2002
E. Brockmann
AGNES net
Geodynamics
GPS meteo
Positioning
Conclusions
Positioning
• Swiss Positioning Service (swipos®)
– swipos - NAV (1-5 meters)
> GPS reference station in Zurich (SRG)
> DGPS correction data (RTCM, Type 1,2 over FM/RDS or GSM)
– swipos - GIS/GEO (cm accuracy)
> RTK service over GSM (0900 - Business Number)
> Nationwide cm accuracy!
EGS Nice, April 2002
E. Brockmann
AGNES net
Geodynamics
• swipos-GIS/GEO is based on the concept of the Virtual Reference
Stations (VRS)
• The approximate position of the user is sent to the central
communication computer over GSM
Conclusions
Positioning
GPS meteo
Positioning (2)
Approx. position
Data
Firewall
Data
VRS observations
(RTCM 18,19)
Field
Communication
Server / VRS
Software
EGS Nice, April 2002
Data AGNES
sites
E. Brockmann
AGNES net
Geodynamics
GPS meteo
• 14 hours test on “swisstopo” roof
• 4 hours RAW / VRS performance test (using antenna splitter)
• Test in different areas and distances and height differences to the
AGNES network
• 2 diploma theses
• Praxis tests: determination of 73 second order points using RTK and
“classical” static GPS
Conclusions
Positioning
Positioning: Performance tests
EGS Nice, April 2002
E. Brockmann
AGNES net
Geodynamics
• Test over 14 hours on the swisstopo roof using a
Trimble 5700 receiver (with GSM)
• Registration of the RTK position every second;
new initialization every 15 minutes
2 cm
2 cm
Conclusions
Positioning
GPS meteo
Positioning: Performance
Horizontal rms: ±1.0 cm (1 σ)
Vertical rms: ±1.8 cm (1 σ)
EGS Nice, April 2002
E. Brockmann
AGNES net
Geodynamics
GPS meteo
Positioning
Conclusions
Positioning: Performance (2)
• Test over 4 hours on the swisstopo roof using 2 Trimble 5700
receiver (with 2 GSM) and 1 Zephyr antenna (+ antenna splitter)
• Registration of the RTK position every second; new initialization
every 15 minutes
2 cm
2 cm
Virtuel:
5% float
2 cm
Raw:
45% float
Horizontal rms: ± 0.7 / ± 0.8 cm (1 σ)
Vertical rms: ± 3.6 / ± 2.5 cm (1 σ)
EGS Nice, April 2002
E. Brockmann
AGNES net
Geodynamics
• 100 seconds to initialization (20 sec. GSM, 80 sec. init.)
• Horizontally 2-3 cm rms, vertically 3-4 cm rms
• VRS results do not show a smaller bias compared to RAW data of the
nearest AGNES site, but the ambiguity resolution and time to
initialization is improved (“factor of 2”)
• 5 satellite constellations for VRS critical (switch to RAW)
Conclusions
Positioning
GPS meteo
Positioning: Performance summary
EGS Nice, April 2002
E. Brockmann
AGNES net
Geodynamics
GPS meteo
• The Automated GPS Network Switzerland (AGNES) consists of
29 permanent GPS tracking stations
• AGNES is a multipurpose network:
– Reference network for the first order surveys in Switzerland
– Analysis of time series of coordinates for geodynamics
– 1-hour data processing (near real-time) for meteorological
applications (numerical weather prediction)
– swipos-GIS/GEO: RTK positioning service with nationwide
cm accuracy
Conclusions
Positioning
Conclusions
EGS Nice, April 2002
E. Brockmann