Applications of Auto-Offset Location Technology
Transcript of Applications of Auto-Offset Location Technology
![Page 1: Applications of Auto-Offset Location Technology](https://reader031.fdocuments.in/reader031/viewer/2022020703/61fb3a3f2e268c58cd5bac73/html5/thumbnails/1.jpg)
Applications of Auto-Offset Location Technology
Jim WaitePresident
2011 Damage Prevention Conference, Virginia Beach
![Page 2: Applications of Auto-Offset Location Technology](https://reader031.fdocuments.in/reader031/viewer/2022020703/61fb3a3f2e268c58cd5bac73/html5/thumbnails/2.jpg)
Utility Geospatial Mapping – Current Method
• Utility location, followed by GPS position
– Locate the peak/null, then survey
• Export depth values and lat/lon/altitude
• Assign attributes
• Convert to local job site coordinates
– Determine East, North, Up (elevation)
• Update GIS database and CAD
Software can automate these tasks
![Page 3: Applications of Auto-Offset Location Technology](https://reader031.fdocuments.in/reader031/viewer/2022020703/61fb3a3f2e268c58cd5bac73/html5/thumbnails/3.jpg)
Gas Pipeline Survey – Typical Result
Each point annotated
with depth, current,
and GNSS error
xxxxxxxxx
x
x
xx
x
xx x
x
Combined locating and mapping accuracy is typically sub-meter
• GPS system reports expected accuracy
• Locating system relies on the competence of the operator
![Page 4: Applications of Auto-Offset Location Technology](https://reader031.fdocuments.in/reader031/viewer/2022020703/61fb3a3f2e268c58cd5bac73/html5/thumbnails/4.jpg)
Desired Process Improvements
• Directly survey the utility from offset positions
• Improve overall accuracy to a decimeter (4”)
• Record locate result with expected “RMS” error
• Reduce the subjectivity of the locate
• Reduce occurrences of poor GNSS signals
• Reduce incidence of non-locatable lines
![Page 5: Applications of Auto-Offset Location Technology](https://reader031.fdocuments.in/reader031/viewer/2022020703/61fb3a3f2e268c58cd5bac73/html5/thumbnails/5.jpg)
Auto-Offset Data Collection
Walk path
Pipeline Survey
![Page 6: Applications of Auto-Offset Location Technology](https://reader031.fdocuments.in/reader031/viewer/2022020703/61fb3a3f2e268c58cd5bac73/html5/thumbnails/6.jpg)
-121.967
-121.9668
-121.9666
-121.9664
-121.9662
-121.966
-121.9658
-121.9656
-121.9654 37.3797
37.3798
37.3799
37.38
37.3801
37.3802
37.3803
0
0.5
1
1.5
2
2.5
10 m N
10 m E
Latitude, o
Gas survey to Scott manhole, , ref: 37.380232oN, -121.965438oW
UTC: 11.02.27.23.09.41, Spar 050051100012
Longtitude, o
Dep
th, m
Spar
Gas pipeline
3-D Geospatial Position
Manhole
cover
Distorted field at
pipeline direction
changes
![Page 7: Applications of Auto-Offset Location Technology](https://reader031.fdocuments.in/reader031/viewer/2022020703/61fb3a3f2e268c58cd5bac73/html5/thumbnails/7.jpg)
Auto-Offset Location
• Direct geospatial mapping of the utility to
sub-decimeter accuracy
• Works from arbitrary perspectives, no
need to be at the peak/null
• Applies measured centerline and depth
offsets automatically
• Wireless networking used for accurate
deep locates
• Uses job site coordinates, not lat/lon
![Page 8: Applications of Auto-Offset Location Technology](https://reader031.fdocuments.in/reader031/viewer/2022020703/61fb3a3f2e268c58cd5bac73/html5/thumbnails/8.jpg)
Arbitrary Orientation and Perspective
Maximum range for
5% accuracy in depth
and offset = 3 meters
![Page 9: Applications of Auto-Offset Location Technology](https://reader031.fdocuments.in/reader031/viewer/2022020703/61fb3a3f2e268c58cd5bac73/html5/thumbnails/9.jpg)
Key Positioning Parameters
Utility offset and depth are merged with 3-D geospatial
position. Expected RMS error is also combined.
![Page 10: Applications of Auto-Offset Location Technology](https://reader031.fdocuments.in/reader031/viewer/2022020703/61fb3a3f2e268c58cd5bac73/html5/thumbnails/10.jpg)
1-σ, 2-σ, or 3-σ Confidence
2-σ = 95%
confidence
interval
Accuracy is proportional to the radial distance from target
![Page 11: Applications of Auto-Offset Location Technology](https://reader031.fdocuments.in/reader031/viewer/2022020703/61fb3a3f2e268c58cd5bac73/html5/thumbnails/11.jpg)
Point Positioning Under Cover
GNSS signal is improved by moving off the line, using the
measured offset for continued accurate target detection.
![Page 12: Applications of Auto-Offset Location Technology](https://reader031.fdocuments.in/reader031/viewer/2022020703/61fb3a3f2e268c58cd5bac73/html5/thumbnails/12.jpg)
Continuous Positioning
Maintain map accuracy with the use of complementary
dead-reckoning components (compass, odometer)
![Page 13: Applications of Auto-Offset Location Technology](https://reader031.fdocuments.in/reader031/viewer/2022020703/61fb3a3f2e268c58cd5bac73/html5/thumbnails/13.jpg)
Measurement Geometry Expansion
Wireless Collaboration
Maximum range for
5% accuracy in depth
and offset = 20 meters
![Page 14: Applications of Auto-Offset Location Technology](https://reader031.fdocuments.in/reader031/viewer/2022020703/61fb3a3f2e268c58cd5bac73/html5/thumbnails/14.jpg)
Underwater Utility Mapping
Above water, the dual-sensor positioning system
is affixed to a non-ferrous vessel to benefit from
the improved measurement geometry.
![Page 15: Applications of Auto-Offset Location Technology](https://reader031.fdocuments.in/reader031/viewer/2022020703/61fb3a3f2e268c58cd5bac73/html5/thumbnails/15.jpg)
Dual-sensor Mapping
(Duct, Tunnel, and Non-metallic Pipe)
Dual-sensor systems are also useful in sonde tracking
applications. Receivers operate from fixed locations.
![Page 16: Applications of Auto-Offset Location Technology](https://reader031.fdocuments.in/reader031/viewer/2022020703/61fb3a3f2e268c58cd5bac73/html5/thumbnails/16.jpg)
Tracking Range for Single and Dual
Receiver Systems
Sensor collaboration permits using the entire breadth of the
emitted field without walkover locating.
Spar 1 Spar 2
![Page 17: Applications of Auto-Offset Location Technology](https://reader031.fdocuments.in/reader031/viewer/2022020703/61fb3a3f2e268c58cd5bac73/html5/thumbnails/17.jpg)
Excavation Machine Control
![Page 18: Applications of Auto-Offset Location Technology](https://reader031.fdocuments.in/reader031/viewer/2022020703/61fb3a3f2e268c58cd5bac73/html5/thumbnails/18.jpg)
Auto-Offset Location Technology
www.optimalranging.com