Thanks very much for your input.
I will give this a try.
Note though that I generally fly at about 8-9 m/s and get very good data at this speed.
I know that there may be some issues that derive out of the rolling shutter on the camera, but that should be individual warping of the image and blur.
The GPS accuracy for the UBLOX tends to be extremely good in general, and relative to it’s own reference it stays very very stable. (sub 0.3 m error over the course of a 20 minute flight) (drone will land within 0.3 of where it took off over 90% of the time, barring heavy wind)
I will try bringing the gps-accuracy down to 5 and see what it does.
I am curious though, do you think this is the issue why it is detecting point cloud values above the surface? It may be that at this point the drone caught a gust of wind and had a rapid movement / shift.
It is very likely that the camera maintained it’s 5 deg off nadir attitude, but it is possible that the drone jumped in altitude / orientation very quickly.
The images are snapped at 1 second intervals. There is also the case that this occurred close to the edge of the field in the over-fly area, where there are more images that average due to slowing, turning and accelerating.
I will follow your steps and see what I get.