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Let’s be frank, there are times when your directly georeferenced airborne camera measurement
don't fit your Ground reference points. Don't panic and re-fly your mission. Don't call
the support team just yet. Let's use QAQC block procedures to find what the issue is.
QAQC (Quality Assurance Quality Control) Block procedures are needed to obtain the maximum
achievable accuracy for integrated mapping systems.
To do this, you need to have a QAQC block area. Now, this is easy: For large block projects,
you can simply extract a small sample area from it. For a corridor mapping project, you
can simply fly a small block at the beginning or end of your first or last flight line.
So, this means you should fly or extract a QAQC block for every mission as backup.
Remember that all parts of the sensor system must be working optimally for direct georeferencing.
QAQC Block procedures resolve issues at the sensor level because we want to put the best
data into production (not the proceeding level, the mapping level). You don’t want garbage
in, because its garbage out. With good input! You can truly increase productivity by producing
more maps within a given period and by reducing field crew time.
To maximize accuracy with direct georeferencing, there are 6.5 items that need to be Quality
Controlled (QC): 1. Lever arms between camera perspective center,
IMU, and GPS antenna 2. Camera to IMU Boresight angles
3. Camera Interior Orientation: Principal Point, Focal length, Lens Distortion
4. Datum transformation parameters 5. GPS Base station coordinates
6.Integrated GNSS/Inertial solution accuracy 6.5 GPS Solution accuracy in cases you're
using loosely coupled processing methods.
The next video will tell you the characteristics or what you need to have in a QAQC block area.
This is GeoErnest.