We recently bought a Phantom RTK UAV. After processing of data, the Z values are significantly different from the control points captured with a GNSS.
What is the procedure to use RTK data in ContextCapture?
I would prefer to not use control points as this is part of the reason for getting the RTK Drone.
At first try to do a calibration if you process only Nadir flights. Also make sure that you use unprocessed(distorted) images and not undistorted(maybe actually could try with undistorted also for test). Undistorted images from RTK are already flattened using factory calibration(DewarpData) so could try to reuse the fixed calibration.
https://communities.bentley.com/products/3d_imaging_and_point_cloud_software/f/contextcapture-descartes-pointools-forum/176371/dji-phantom-4-rtk-ntrip-processing/510761#510761
So basically what is needed for RTK processing:
1. Create local coordinate system with your locally used geoid which was used for GCPs.
2. Import images and set "GPS Altitude reference" to WGS84. At least for me it seems that DJI for RTK uses WGS84 for GPS altitudes whereas in non-RTK products the GPS altitude tag contains barometric altitude.
3. Reuse precalibration parameters.
Other method if launch altitude is known we could do aerotriangulation 2x times, first to get the wrong altitudes then adjust the altitudes by known difference and run aerotriangulation again.
Also seems that CC is too relax even when using accurate metadata setting so need to fix rtk positions by using aerotriangulation setting orientation-keep. Honestly aerotriangulation will not improve results if rtk positions are actually accurate.
In aerotriangulation settings try modifying position/rotation estimation policies as shown in image attached. You can try also put keep in position but i suggest use adjust with a bit of tollerance.
It should work good. Let me know something when you try with your dataset. I'm waiting for feedback.
Yes it seems until CC can use RTK accuracy for each photo until then there is need to set adjust with tolerance where tolerance is maximum deviation. But I had seen that even with adjust it moves photo in unrealistic positions. Contextcapture is not RTK ready yet(edit: resolved in U15). RTK Input:Result with accurate metadata(block type nadir, structured,generic,orbit doesn't care):
Result with keep positions:
did you tried with accurate metadata and then in at setting adjust poition 0.05 tollerance and rotation adjust?