Transcript of Positioning with LiDAR Lucia Scimone, 31 st May 2011 GMAT9205 – Fundamentals of Geo-Positioning...
- Slide 1
- Positioning with LiDAR Lucia Scimone, 31 st May 2011 GMAT9205
Fundamentals of Geo-Positioning School of Surveying and Spatial
Information Systems The University of New South Wales Lucia
Scimone, 31 st May 2011 GMAT9205 Fundamentals of Geo-Positioning
School of Surveying and Spatial Information Systems The University
of New South Wales
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- Aims What is LiDAR? How it is collected XYZ Positioning What
does it look like Limitations
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- Background Australian Hydrographic Office Why? - Marine
Navigation, Charting, Environmental Research, Mining /Exploration
Shallow water bathymetry, eg. Greet Barrier Reef Source:
www.fugrolads.com
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- Bathymetric Acquisition Methods Source: (left)
www.cairns.com.au (right) www.personal.psu.edu
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- LADS Hydrography Source: Australian Hydrographic Service LIDAR
- Light Detection and Ranging. Laser Airborne Depth Sounder (LADS
II) fitted in a de Havilland DASH 8 aircraft. Land Based
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- Lidar Data Collection Source: www.personal.psu.edu
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- LiDAR Data Collection Airborne LiDAR system consisting of
lasers, scanner, optics, and acquisition, electronics. Picture:
Andreas Axelsson, (2010) Rapid topographic and bathymetric
reconnaissance using airborne LiDAR, Proc. SPIE, Vol. 7835,783503
Sweden accessed online at: www.airbornehydrography.com
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- Lasers L-A-S-E-R : Light Amplification by Stimulated Emission
of Radiation two frequency beams Green laser pulse 532 nm, pulsed
(neodymium-doped yttrium aluminum garnet green laser) Red laser
pulse (near infrared beam) 1064 nm Each laser footprint is around
2.5m diameter, green beam passes through water and diverges due to
light scattering. Source: Axelsson 2010
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- Remember last weeks GMAT 9205 Lecture on GPS/INS Integration
for Geo-referencing (Week 10)? Positioning Aircraft altitude and
speed need to be considered when collecting data: Laser Time return
Sampling rate Sub-ns accuracy for timing calibration Beam
divergence Target characters
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- Positioning - xyz Vertical & Horizontal Altitude of
aircraft GPS / INS (Inertial Navigation System) Both onboard and at
a station on the ground Tides system's operating geometry
propagation induced biases wave height Source: ttp://coastalwiki.or
g/w/images/8/8b/Li dar_fig_02.jpg
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- Positioning - xyz The body frame (b-frame) is an orthogonal
frame in which the measurements of a navigation system are made. -
Origin: The centre of the navigation system - X-axis: Toward the
front end of the vehicle - Y-axis: Toward the right side -Z-axis:
Downwards and perpendicular to the X-Y plane -(Wang 2011, Lecture
10) The navigation or local level frame (n or l- frame) - Origin:
The centre of the navigation system - X-axis: Toward ellipsoidal
true north (North) - Y-axis: Toward ellipsoidal east (East) -
Z-axis: Downwards direction along the ellipsoidal normal
(Down)
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- Limitations Depth of water < 60m Conditions need to fly
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- Questions