I was catching a flight and was in the process of shutting down when I posted .. these control points are mostly on the bridge as part of the terrestrial photos - so 2mm GSD with a Canon - just happened to be at the top of the list. So even less accurate GPS on that thing. The control was shot in by survey-grade laser scanner and is typically good to about 2mm. The airborne stuff is a little looser - but not by much - we were flying about 15m. Again the control on the bridge deck was survey-grade from either scanner or total station. We were chasing some pretty tight tolerances for steel work. You can get results like these without any GPS on the UAV at all - that was the point I was trying to make - and in fact - if relying on RTK/PPK - the results would have been worse. Will probably re-run this with the new version which I see is avail for download given the new point cloud alignment functionality.
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