Transcript New Technology Initiatives in West Virginia

2010 LiDAR Collection in West Virginia’s
Coal Fields
West Virginia GIS Conference
June 9, 2010
AOC and future mining  LiDAR
Slide 2
LiDAR collection specifications
• Horizontal postings: 1 meter
• Vertical accuracy: 15 centimeters
• Additional derived data products
include:
– ESRI elevation grid
– Hillshade
– 2 foot contours used in AML program
– Intensity image  useful in QCing LiDAR data
• ~ 2 TB of data before derived products
Slide 3
LiDAR Technology
LiDAR = Light Detection And Ranging
•Capable of emitting 100,000 pulses per
second at altitudes less than 1,100
meters
•Day or night operation
•Capable of collecting millions of
elevation points per hour
•All digital: no intermediate steps to
generate digital XYZ
•Rapid turnaround: Capable of
processing within a week
•Multiple returns per pulse
•Airborne: Easy to mobilize and
demobilize
•Non-Intrusive: capable of accessing
remote areas

Solid state Class IV laser

Swath width: Variable; 0 to
0.93 x altitude (m)

Horizontal Accuracy: 1/2000
x altitude

Elevation Accuracy: +/- 15
cm (or better)

Typical spot center spacing is
from 0.5 m to 5.0 m
Slide 4
Workflow
•Acquisition
NOAA
Processing
Product
Slide 5
Flight Planning
•Pulse rate frequency (PRF)
•Scan frequency
•Scan angle
•Desired overlap
•Altitude
•Make sure above parameters yield
an acceptable resolution
Slide 6
Acquisition Process
•
•
•
•
Pre-Flight
– Check aviation weather
– Review day’s mission with pilots and ground crew
In Airplane
– Check system
– Power up
– Communicate with ground control operator
– Initialize GPS/IMU
In Flight
– Transit to project area
– Begin collection
– Constantly monitor conditions during collection
– Keep flight log
Post Flight
– Final initialization on GPS/IMU
– Power down
– Retrieve removable hard drives for data decoding and processing
Slide 7
Ground Control
Two Topcon Hiper dual frequency static GPS
receivers equipped w/ FC-100 controllers.
20 channel integrated GPS receiver
Signals Tracked – L1/L2 C/A Code and P Code
(dual frequency)
76 mb of Memory
Advanced Multipath Reduction
Logging Intervals of up to 20 times per second
(20Hz)
Horizontal – 3mm + 0.5ppm
Vertical – 5mm + 0.5ppm
Cold Start - < 60 sec
Warm Start - < 10 sec
Reacquisition - < 1 sec
Slide 8
Ground Control
Ground GPS Requirements
• Base station must be within 30 km (18 miles) from airborne laser.
• Use dual frequency GPS receivers.
• Use two highly accurate published geodetic control points during
airborne data collection to provide redundancy.
• PDOP of 4 or less, optimal 3 or less.
• Data collected from at least 6 satellites at 1 second epochs.
• Base stations must have a clear view of the sky with limited
mulitpath.
Slide 9
GPS Planning
Slide 10
SBET
Slide 11
Processing Workflow
ALTM
Storage
Download
Hard Drive
QC Data
Extract / Decode
Laser Data File
Process GPS
IMU
Information
Raw Laser
Data
PosPac
Compute
Laser Points
Output
Laser Points
Microstation
Slide 12
Calibration
Slide 13
Building an ICI (=isolated computing island)
• Isolates one or more VERY high
performance computers from central IT
C&C during VERY long compute jobs:
– No pushes of server OS upgrades
– … followed by the requisite reboots
– Isolate from dependence for TIPS licenses
via pool of WVDEP licenses  network
outages
– Enough local storage to create a peer-topeer within-the-room network
– UPS on each PC
Slide 14
PC specs
• HP800 workstations with 64 bit OSes 
super modular.
• Single quad core CPUs  5th fastest on
the planet when we purchased the boxes
• 16 GB RAM & 6 TB each local storage
• 4 megapixel displays + CUDA card
• Isolated peer-2-peer network when
working off the net
• Gigabit network connections for on Net
• Local licenses of all core apps
Slide 15
Qcing LiDAR and LiDAR software
• QCing LiDAR deliverables
– 2003 Statewide GCPs file
– Multiple LiDAR datasets that overlap 
difference grid calculation
– Trimble R8 GNSS receivers for spot
checks
– Outsource via FEMA monies
• Software  64 bit, use multicores
– Virtual Geomatics
– Applied Imagery’s Quick Terrain Modeler
Slide 16
WV
CORS
The end
Slide 18