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Mobile Laser Calibration
Calibration Guidelines for Mobile Laser Calibrations
1. Establish approximate Roll, Pitch and Yaw C-Os based on
mechanical drawings
2. Establish accurate Offsets between INS/MRU and the GNSS
antenna3. In case ofmultiple scanners, make sure the measured
surface directly below the
scanners shows identical profiles for the Z
4. In case ofmultiple scanners, calibrate each scanner
individually
5. Calibration order: Roll Pitch Yaw Latency
6. Verify the absolute X, Y and Z by placing known reference
objects inside the
calibration area7. Verify zero timing latency by slow and fast
run
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Mobile Laser Calibration
Run 1Run 2
Run 3
+/- 50 m
Pitch Calibration ObjectYaw Calibration Object
Roll Calibration Objects
+/- 150 m
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Mobile Laser Calibration
Run 2
Run 3
+/- 50 m
Run 1
Pitch Calibration Object
Yaw Calibration Object
Roll Calibration Object
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Mobile Laser Calibration
Pitch Calibration Object
Yaw Calibration Object
Roll Calibration Object
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Mobile Laser Calibration
Roll Calibration
1. Method A - No correction for GNSS Z variation between
opposite runs
Laser origin run 2
a
b
Laser origin run 1
2. Method B - Correct for GNSS Z variation between opposite
runs
Laser origin run 1+2
c
d
Height variation between run 1 and 2
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Mobile Laser Calibration
Before Roll Calibration
After Roll Calibration
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Mobile Laser Calibration
a
b
Pitch Calibration
Run 1Run 2
a
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Mobile Laser Calibration
Before Pitch Calibration
After Pitch Calibration
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Mobile Laser Calibration
Yaw Calibration
Run 1
Run 3
Laser origin run 3
Laser origin run 1
b
a
d
c
+/- 50 m
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Mobile Laser Calibration
Timing Verification
Run 1 approx 2 knots
Timing run approx 8 knots
1. With zero latency both objects line up
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Mobile Laser Calibration
Car based laser calibrations
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Mobile Laser CalibrationPitch Calibration Object
Yaw Calibration Object
Roll Calibration Objects
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Mobile Laser Calibration
Use Swath View for Roll Calibration
Define Scroll Line
Perpendicular to Scanner
Roll Calibration
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Mobile Laser Calibration
Use Profile View for Pitch Calibration
Define Scroll Line
Perpendicular to Scanner
Pitch Calibration
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Mobile Laser Calibration
Use Swath View for Roll Calibration
Define Scroll Line
Perpendicular to Scanner
Yaw Calibration
Use Profile View for Yaw Calibration
Define Scroll LinePerpendicular to Scanner
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Mobile Laser Calibration
Pitch Calibration Object Yaw Calibration Object
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Mobile Laser Calibration
Timing Verification
1. With zero latency both objects line up
Run 1 5 km/hr
Latency Run 40 km/hr
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Mobile Laser Calibration
Left Scanner Right Scanner
INS
CoGGNSS
Driving Direction
Scan Origin
Left Scanner
Roll offset = - 90 degreesPitch offset = - 35 degrees
Heading offset = + 30 degrees
X offset = - 0.335 m *
Y offset = - 0.200 m **Z offset = - 0.144 m ***
* To the right of the car is +
** To the front of the car is +
*** Below CoG is -
Right Scanner
Roll offset = + 90 degreesPitch offset = - 35 degrees
Heading offset = - 30 degrees
X offset = + 0.335 m *
Y offset = - 0.200 m **Z offset = - 0.144 m ***
Example : Riegl VMX250
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Mobile Laser Calibration
INS
CoG
GNSS
Scan Origin
Example : Leica HDS6000
Scanner
Roll offset = - 180 degrees
Pitch offset = 0 degrees
Heading offset = 0 degrees
X offset = - 0.000 m *
Y offset = - 0.380 m **Z offset = - 0.044 m ***
* To the right of the car is +
** To the front of the car is +*** Below CoG is -
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Mobile Laser Calibration
Example : Riegl VQ250
GNSS Sailing DirectionScan OriginScanner
Roll offset = 0 degrees
Pitch offset = 0 degrees
Heading offset = + 180 degrees
