1 David Le Goff Soldata Asia – General Manager April 2017 Automatic Deformation Monitoring System
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David Le Goff
Soldata Asia – General Manager
April 2017
Automatic Deformation Monitoring System
o Soldata designed and developed in 1997 their “real time” theodolite system and software as a partnership with the French Institut Geographique National (IGN) (UK Ordnance Survey)
o The Amsterdam (North South Line) challenge in early 2000 :
The first “city scale” real time theodolite system with around 75 total station to cover 3.7 km of tunnel and
deep station.
o Currently in the world more than 400 ADMS are managed by Soldata, 75 of them in Hong Kong.
A monitoring system designed by surveyors
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Remote Monitoring using RTS3
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o Easy installation
o Wide coverage area, and easily extendable
o 3D data at each monitoring point.
o Easy calculation of various parameter between multiple monitoring targets.
Advantage of the ADMS solution
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Complete understanding of structure movement
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o Easy installation
o Wide coverage area, and easily extendable
o 3D data at each monitoring point.
o Easy calculation of various parameter between multiple point.
o Precision/Repeatability (usually +/-1mm at 100m distance)
Advantage of the ADMS solution
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Accuracy and Precision7
o Accuracy: correctness with which a measured value represent the true value
o Precision: closeness of agreement between independent test results
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o Easy installation
o Wide coverage area, and easily extendable
o 3D data at each monitoring point.
o Easy calculation of various parameter between multiple point.
o Precision/Repeatability (usually +/-1mm at 100m distance)
o Near real time monitoring
o Low maintenance
Advantage of the ADMS solution
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Working Principle: Taking readings
• Raw readings taken on all the targets.
• TS aimed in general direction of target
• ATR of the TS position locked the center of targets (ATR=Automatic Target Recognition)
• Reading taken, and move to the next target
« Shoot files »
Polar coordinates (Hz, V, D) of each target
Pro
cess L
ocatio
n: T
ota
l Sta
tion
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Working Principle: from Polar to Cartesian Coordinates
• Least Square calculation to determine position of the TS• Recursive calculation =>best fit solution which comply with the survey network requirement
• Reference targets. Target whose position is known and stable (local or HK grid)
• Position of the monitoring targets calculated.• Basic Polar to Cartesian transformation
X, Y, Z of every target (Northing, Easting, Elevation) available
Pro
cess L
ocatio
n: B
ack O
ffice
Data CalculationTrigger CheckData Storage
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o Structure/Building monitoring
o Track/Tunnel monitoring
Typical Application
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o Number and location of reference targets
o Recommend 10 reference targets for one Total Station
o As much as possible evenly located around the Total Station
o Precision of the system strongly dependant of this factor
o Problem of tunnel monitoring
o 1 shot two face as a minimum
o Eliminate internal error of the instrument
o From experience can be done at end of cycle.
o Weather data compensation on raw readings
o Temperature and Pressure affect the distance measurement
o No correction on Hz and V readings
Key Factor of a successful ADMS monitoring
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o Baseline period
o Better understanding and assessment of the system
o Temperature/seasonal movement assessment
o Appropriate AAA level determination
o Automatic but need to be monitored/maintained
o Many quality factor are tracked in real time
o Levelling of the Total Station (compensator limit)
o Reference targets adjustement.
Key Factor of a successful ADMS monitoring
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o Number of targets
o Assumption of the least square calculation is the TS does not move during one measurement cycle=>cycle can not last too long.
o For a 30mns cycle, we can monitor up to 60 targets
o Line of sight issue
o Optical system need a clear line of sight between TS and target
o Issue in heavy rain environment
o Precision of the system drop with distance
o Although possible to monitor at long distance, the precision is directly affected
o Affect the monitoring targets and the reference targets
Limitation of ADMS system
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o Use data from multiple ADMS in one single group calculation
o Extend the monitoring area
o Goes around line of sight obstruction
o One referential system
• Introducing the “share targets”
• Target seen by multiple ADMS
• Create a link between multiple ADMS
Improved ADMS : the Group of ADMS
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Design optimisation: A key for a performing system
KEY POINTS for a good design and reliable system:
• A “sufficient” number of stable reference prism for the all group
• A sufficient number of “sharing” prisms between Cyclops.• The “azimuth” repartition of the reference and sharing prisms.
• Sufficient redundancy (occasional interruption of “line of sight” is unavoidable”)
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o One referential system
o X,Y and Z axis is global to the group => possible to compare data of different ADMS
o Improve accuracy by better spreading of reference targets
o Monitoring of very large area
o ADMS with no direct access to reference target is possible.
o Goes around line of sight issue
Advantage of Group of ADMS
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Typical Application of Group of ADMS in HK – SCL 1112
• Around 70 ADMS split in multiple group (group of 15)
• More than 2500 targets monitor every 30mns
• More than 10,000 data point every 30mns
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Typical Application of Group of ADMS in HK – SCL 1121
• 22 ADMS to monitor CHT westbound tunnel (from Kowloon to HK)
• Very challenging project due to reference layout and temperature effect
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o Monitoring of large scale tunnel project in urban environment
o Amsterdam North South Line
o Barcelone Line 9
o Toulon Highway Tunnel
o London Crossrail Project
o Seattle Alaskan Highway
• Still remain one issue: need to install a target
Typical Application of Group of ADMS
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• RRTS = Robotic Total Station + Reflectorless capacities
• No ATR (Automatic Target Recognition)
• No intrusion
• Performance related to:
�Range
� Incidence angle
�Weather conditions
�Surface material and roughness
�Surface homogeneity and slope
�Traffic (vehicles, pedestrians, trains, trees leaves, etc..)
αααα
R
Reflectorless Monitoring - Centaur
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Reflectorless Monitoring - Principle
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• Multi-point:
+ Robust
�Very accurate
�Constant interpolated XY
�Tolerates temporary obstructions
- Heavy and slow
�Lower spatial and temporal resolutions
“n” measure points with suitable repartition
1 interpolated point with constant XY
Two Technics available: 1. the mesh method
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• Mono-point:
+ Fast
�More points � Better spatial resolution � Better temporal resolution
- No redundancy
�More noise
�More readings discarded
�XY potentially variable
Two Technics available: 2. Mono point version
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• Pavement, roads, highways, utilities
Centaure Application
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• Vertical walls: shafts, portals, cliffs
Centaure Application
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Typical Application of Reflectorless ADMS in HK – SCL 1109
• 1 ADMS
• Combine system standard target monitoring and reflectorless
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Typical Application of Reflectorless ADMS in HK – HY/2011/03
• 4 ADMS in group
• Combine system standard target monitoring and reflectorless
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+Silent instrument
+Minimal maintenance
+3D monitoring of objects
+Easily interpretable
+CENTAURE avoid human intrusion on road ways
+Coverage of large areas (with groups eventually)
ADMS and Centaure Application – Added Value
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- Create (minor) damages to structures
- Require power source
- Visible to General Public
- Not real-time monitoring
- Optical readings: obstacles, weather, etc..
- Wireless communication: coverage and interference
- Vandalism and theft
Centaure Application – Inconvenients
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Other Improvements of ADMS system
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� For large distances monitoring (1, 2, 4 km), when the ATR does not work.
Recent improvements : “Signal intensity centering”
Position courante de la lunette
Champ de vision de la lunette de station totale
Prisme déjà à peu près centré
�
�
�
� �
Lunette centrée sur le prisme
Mesure de la distance
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� Linux equipment piloting total station
Recent improvements: NOMAD – Low power CYCLOPS
Power Consumption in Ah
parameters: cycle of 30min with 60
cibles
Current ADMS NOMADCYCLOPS + Modem
(pas de backup local)
24h/24 40 17 22
6 h/24
(1h every 4h)33 10 19
3 h /2432 8 19
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� Soldata’s monitoring systems have always been designed to reject poor quality calculation (if for example not enough reference targets or sharing targets available
due to obstruction of line of sight or theodolite malfunction) � Full Quality Mode
� From discussion with some clients.. Availability of data is sometimes more critical
than accuracy.
� Soldata have developed and implemented the “full availability” or “degraded mode”
to provide values when part of the system is “not so good” � subgroups, etc…
Recent improvements: “full availability” and “full quality”
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� GPS Solution� 3D Data at every point
� No Reference point or only one reference point
� Need power source at every monitoring point
� Bulky
� Accuracy not as good as ADMS
� Cost
� LiDAR or point cloud monitoring� 100% reflectroless
� Infinite number of points
� Mapping, 3D Model tool
� Processing power
� Cost
The futur of ADMS
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THANK YOU
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