The document summarizes the process of collecting and processing LiDAR data from aircraft for geospatial applications. Key steps include planning flights to cover a project area, flying the aircraft equipped with a laser scanner and GPS, processing raw laser and GPS data to determine point locations, extracting useful data, ensuring accuracy by inspecting overlaps between flight lines, and delivering the final data products to clients.

1. Making Lasers Useful

3.  Small but growing company, ~ 35 office
employees plus flight staff
 Located in Fredericton, N.B.
 Fly projects throughout North America, largely
focusing on Eastern Canada and the U.S.
 Process LiDAR data and create products for
clients: DEMs, DSMs, etc.
Aircraft

4.  Get a project through bidding or other contract
talks
 Create a planned flightpath based on the project
area
 Fly the project, sometimes spanning several flights
on multiple days. This can occasionally require
more than one plane
 Process the trajectory and information from the
laser system to determine where the plane was and
where the points are in 3d space
 Create a digital product based on client
specifications
1pt/m² 6pt/m²

5.  Largely, I take the raw data from the plane and
create LAS files that can then be used by
different GIS software (Arc, Global Mapper,
etc) to create the products
 This processing includes determining the
accurate position of the plane in 3d space, and
then processing the raw laser data into
something more useful

6.  A system on board the plane uses a high
quality GPS and IMU to determine where the
plane is at that moment in time
 By having a measurement every second, we
can process these into a single trajectory that is
useful for later processing

7. POSPac showing base stations located around a study area

8.  I do!
 Knowing what the plane was
doing is incredibly important
 The information from the laser
only tells us how far the point
was from the plane, it has no
geographic information
associated
 We need to use the information
from where the plane was to
associate the returns with a
geographic coordinate

9.  Comes a full
waveform data –
multiple possible
returns to be used
 These returns need
to be extracted to be
used as points
 Done with software

10.  MTA – Depending
on altitude and pulse
rate, more than one
pulse can be in the
air at one time
 Need to determine
which Zone you are
in to ensure the
software interprets
returns correctly

11.  We know where the LiDAR sensor was based
on the trajectory processed earlier
 We know how far the returns are from the
aircraft based on the already processed raw
waveform data
 Bringing these together allows us to place them
on the earth, with a projection if required

12.  Hopefully at this point, nothing went wrong
 More than likely, something did
 Visual inspections are made to see whether the
different flight lines are “tight” to one another
 If they aren’t, some adjustments can be made
 If these adjustments won’t work, a better
trajectory may help fix some of the issues
 If the data is unrecoverable, the flight needs to
be done again – an expensive proposition

15.  Create LAS files to further QC data
 Use points collected by survey to see whether
or not the data agrees with where the ground is
 If points agree with reality, and the final area
covered by the LAS fits with the area
determined by the client, I’m done!

16.  Quite well
 Although we never covered how to do this
type of work, the ideas behind the process were
explained well enough that I feel after a little
training I am already able to be useful

17.  COGS
 Leading Edge Geomatics