Steve AuCoin & James Thompson's presentation at Geomatics Atlantic 2012 (www.geomaticsatlantic.com) in Halifax, June 2012. More session details at http://lanyrd.com/2012/geomaticsatlantic2012/sryrx/ .

1. Geographic Sciences Diploma – Remote Term Project: Jan – May
Sensing 2012
Development of an
Open-Source Based
Direct
Georeferencing
Thermal Camera
Team DGATS: Led by:
James Thompson & Steven System Trevor Milne the Mastermind
AuCoin

2. What is Direct Georeferencing?
Source: UNB Geodesy and Geomatics Engineering Lecture Notes; Guide to GPS Positioning (1999).

3. Positional Information is post-
processed to acquire full benefit
from Carrier Phase GNSS
The Inertial Measurement Unit
and GPS system (PosAV) creates
a very accurate path known as
Smooth Best Estimate of
Trajectory (sbet)

4. Sensors Used
FLIR A615 Thermal Canon Rebel RGB
Camera Camera
• FOV = ~45° • FOV = 43-°
• Focal length = 13.1 mm • Focal length = 28 mm
• Sensor = 8.11 x 10.82 • Sensor = 14.8 x 22.2 mm
mm
• Spectral range = 7.5 – 13
µm

5. Positioning Equipment
Applanix Position and Orientation System for
Airborne Vehicles (POS AV)
2
1. PCS 1
2. GNSS antenna
3
3. IMU

6. Power Requirements
Device Amperage Voltage
POS AV 2.5 A 24 V
Network Hub 1.2 A 12 V
Pilot Display 1.5 A 12 V
FLIR 2A 12 V
RGB 2A 8V
Batteries Amp Hours Voltage
2 x 12 VDC 55 A.H. @ 20Hr 24 V
1 x 12 VDC (gel) 51 A.H. @ 20Hr 12 V

7. Circuitry
• All equipment powered
with three 12V batteries
• Two 12V batteries wired in
series for the POS AV,
stored in box 1
• Gel-cell 12V battery used
in box 2 for remaining
equipment
• 12V converted to 8V for
the RGB camera

8. Box 1 - Schematic

9. Box 2 - Schematic

10. Software Development Kits
System Requirements: C language interface that
An IDE which understands recommends using Microsoft
ActiveX components eg. Visual Studio for Development
Visual Basic, Visual C# projects
etc.

11. Position and Timing
We need to use the POS’s User Datagram
Protocol stream to make decisions and to
update the Pilot’s onboard display
DGATS receives UDP updates once per
second
IMU records platform attitude 200x per
second
IMU speed and accuracy are important because the plane speed averages
above 50 m/s. GPS signal restrains IMU from ‘drifting’ and gives real world
coordinates.
The ‘datagrams’ are binary packages of information that require restructuring
in DGATS before being used for processing. The information is constantly
varying in length and data types.
This functionality could not interfere with the user-driven interface, but
how?

12. A Complex Event Driven Program

13. User Interface for a complex event driven
program
Show picture of
DGATS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!

14. Planning a Flight
Lots of preflight planning and information had to
be compiled and either integrated into DGATS
or the flight maps.
We
needed:
Sensor specifications:
- Sensor size and focal length to calculate image footprints and airbase to
ensure correct overlap for our flying height
- Equation: fl/ss = H/D
Survey specifics and terrain details:
- Subject area was the Middleton Transect
- AGRG provided LiDAR data for DEM and post-processing
Flight details:
- Weather and timing were essential.
- Expected the morning flight to have best thermal information.

15. Middleton
Transect Planning
Map
This was distributed to all the parties
involved in the flight. It indicates the
primary subject area as well as the
lines required (indicative of time). The
elevations seen in the DEM overlay
posed the next problem.
Our system processes and records
information in the GPS standard
WGS84 datum. Photogrammetric
accuracy and the DGATS decisions
require height above ground level
(AGL) to be used.

16. Pilot Display

17. Lever Arm Offsets
GNSS – IMU IMU – RGB
• Initial X, Y, Z • X, Y, Z
-5 cm, 0 cm, -87.5 cm 2.5 cm, 0 cm, 37 cm
• Calibrated X, Y, Z IMU – FLIR
-5 cm, 2.8 cm, -91 cm • X, Y, Z
-1.5 cm, 10.5 cm, 37 cm

18. Installation
Cessna 172
• Single engine
• Fixed-wing
• Maximum altitude
of 14 000 ft.
• Maximum speed of
124 ktas

19. Installation
Mount supports both sensors and the IMU

20. Installation
Vertically oriented cameras
All equipment installed in cargo

21. Preliminary Results
No electrical
malfunctions in flight!
Plenty of power!
Software functioned
flawlessly. Logs
successfully recorded
events and times.
Initial estimates indicate a potential residual of 2 metres for
RGB imagery.
This is a product of a 40 millisecond delay in the camera
events.
For context, a blink takes 300-400 milliseconds

22. Potential
Applications
& Future Projects

23. Morning
NSCC Middleton Campus
- Maximum Temp. 38 C

24. Afternoon
NSCC Middleton Campus
- Maximum Temp. 44 C

25. River Temperature
and
Sewage
Temperature

26. Acknowledgements
COGS
Trevor Milne, Paul Illsley, Bruce Hicks, Brian Pyke, Dave
MacLean, Jim Norton, Dave Wedlock
AGRG
Dr. Timothy Webster, David Colville, Suzanne Monette,
Theresa Constantine-Smith
ESET
Scott Henderson, Dennis Kingston
Greenwood Flight Center
Allen Jacob