I use CORS from TxDOT RTN to georeference DJI Phantom 4 RTK and Emlid Reach RS2. I have been using it in Corpus Christi, TX with no issues. I do Structure from Motion (SfM) in Metashape, verify the check points and the error is within my expected range (2-5 cm).
I recently travel to Weslaco, TX which is 2 hours away from here. I made sure RTN was connected successfully and GCPs where surveyed only when it has a fixed correction. I used a tripod to keep the Reach level and recorded each GCP for about 30 seconds.
For the data collected in Weslaco, reported in Metashape, I am getting an error of 1-3 meters for the check points. We resurveyed the GCPs and the same error was reported twice.
On the Reach we use vertical datum Ellipsoidal height and NAD83(2011)/Texas South as the coordinate system.
What is the source of this error and how can it be fixed? My understanding is that Reach detects automatically the closest mount point and connects to it.