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

Slide 4 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 5 Acquisition NOAA Processing Product Workflow

Slide 6 Pulse rate frequency (PRF) Scan frequency Scan angle Desired overlap Altitude Make sure above parameters yield an acceptable resolution Flight Planning

Slide 7 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 Acquisition Process

Slide 8 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 Ground Control

Slide 9 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. Ground Control

Slide 10 GPS Planning

Slide 11 SBET

Slide 12 ALTM Storage Download Hard Drive QC Data PosPac Extract / Decode Laser Data File Process GPS Compute Laser Points Output Laser Points Microstation Raw Laser Data IMU Information Processing Workflow

Slide 13 Calibration

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-to- peer within-the-room network –UPS on each PC Slide 14

PC specs HP800 workstations with 64 bit OSes  super modular. Single quad core CPUs  5 th 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 Slide 16 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

WV CORS

The end Slide 18