Drone to DEM Methods of UAS Data Acquisition and ...€¦ · • Certificate of Waiver or...
Transcript of Drone to DEM Methods of UAS Data Acquisition and ...€¦ · • Certificate of Waiver or...
Drone to DEM Methods of UAS data acquisition
and assimilation into GIS
Robert K. Garst
Project Goals
• Capture aerial images with a model aircraft
• Create a dense point cloud of the subject area to produce the following products
• Digital Elevation Model
• Orthophoto Mosaic
UAS User Groups
• Business Users
• Apply for exemption
• Operate with FAA airworthiness certificate
• Both require COA
• Public Entities
• Certificate of Waiver or Authorization
• Recreational Users
• Hobbyist Rule
Commercial Use
• What is Commercial Use?
• Selling media recorded from UAS
• Using a UAS for contract services
• Provide professional services with UAS
• How to operate UAS with commercial purpose?
• Apply for Exception, and COA
• Obtain an FAA airworthiness certificate, and COA
Public Entities
• Governments, law enforcement, public colleges and universities
• Requires only a COA
• Processing time takes approximately 60 days
• A COA has a predetermined term
• Online application
Recreational Users
• No FAA authorization or COA required
• Cannot exceed 400 feet in altitude
• Do not fly near restricted airspace or air fields
• Yield to all other aircraft
• Join the Academy of Model Aeronautics!
UAS Components
• Aerial Platform
• Camera System
• Data Link
• Ground Control
Aerial Platform
• Multicopter design
• Vertical takeoff and landing
• Lower flight speeds
• Tight hardware and software integration with other components onboard aircraft
• Stable camera platform
http://joshanon.com
Camera System
• Small, lightweight payload
• 12MP resolution
• Standard “Fisheye” lens replaced
• Three axis gimbal mount
Lens Focal Point
35 mm Equivelant
HorizontalFOV
Stock Lens 2.92 mm 16.21 mm 123º
New Lens 5.40 mm 29.97 mm 62º
Stock Fisheye lensHFOV: 123 degrees
Replacement lensHFOV: 62 degrees
Camera System
• Small, lightweight payload
• 12MP resolution
• Standard “Fisheye” lens replaced
• Three axis gimbal mount
Lens Focal Point
35 mm Equivelant
HorizontalFOV
Stock Lens 2.92 mm 16.21 mm 123º
New Lens 5.40 mm 29.97 mm 62º
Data Link• Autonomous control
• Interface through iPad Ground Station software
• Fail safe - home coordinates and redundant radio set with traditional controller
Ground Control
• Provides horizontal and vertical control for the model
• 101 reference points collected
• 10 used to georeference model
• 91 reserved for verification
http://www.leica-geosystems.us
UAS Demonstration
Flight Plan Details
• 8 flight strips spanning the neighborhood
• Minimum 60% image overlap required
• Actual sequential overlap: 90%
• Actual flight strip overlap: 70%
• Flown 300 feet above the surface
• Flown at noon for best lighting
• 521 raw photographs
Raw Photograph Overlay
Wild HeerbruggStereo Plotter A8
http://www.officemtt.com
Agisoft Photoscan Pro Workspace
Photoscan View Points
Ground Control
• 10 points used for georeferencing the model
• 91 points reserved for verifying model
Horizontal Error Vertical Error Combined Error
Absolute Error of Point Cloud
Digital Terrain Model
Photoscan View Points
Orthophoto distortionExample #1
Orthophoto distortionExample #2
Orthophoto resolution: 1 inch per pixel
USDA
Disadvantages and Advantages
• Disadvantages
• Resource intensive
• Artifacts present at large map scales
• Advantages
• Produce three products - LAS Dataset, DEM, Orthophoto
• Inexpensive
• Quick turn around time
Acquire Photographsof Subject Area
Align Images and Create “View Points”
Build SparsePoint Cloud
Build DensePoint CloudBuild Polygonal Mesh
Register Modelinto FL East
Coordinate System
Rebuild DensePoint Cloud
Rebuild Polygonal Mesh
LAS Dataset Digital Elevation Model Orthophoto
Apply Photographs to Poly Mesh
GIS
Drone to DEM Methods of UAS data acquisition
and assimilation into GISRobert K. Garst