We have 4 RS3s currently, and a RX - all of which are usually very accurate…however today we had a bit of a scare on a road alignment after carrying out a survey on it.
See below screenshots - you can see that the survey points for the majority of the survey tie into the proposed/built road perfectly in both XYZ, however the first 10 points of the survey have an elevation error of around 9m, and XY error of approx 2m. (yellow boundary in snapshot)
All points were recorded with a FIXED solution, and all RMS errors no more than around 30mm. PDOP & GDOP were also within tolerance - all below 2 approx
From the CSV report, I can see that the engineer recorded these points in the first few minutes of the survey - im unsure of how long he left the RS3 to bake before recording measurements. I assume he left it long enough for the rover to gain a FIXED position as per report.
I also have a few other surveyed points which are showing around 100mm-150mm difference in elevation from design surface & drone survey (drone survey has been tied into local control nails where the error in height is) again this is showing a good FIX position. (blue boundary in snapshot)
Just to add to this, I am aware of the limitations with rtk in built up areas; with multipath etc, however I would expect/hope for the rover to drop into FLOAT or have a higher RMS error which would at least give us a better understanding of what points we can rely on and what we can’t
Looks like those first points were right in between building and a set of conex boxes? How long did you let it cook before you started? Did you do a check-in shot first before doing the topo? Or did you actually just start up there and start shooting?
Hey Michael
Not sure how long it was left to bake exactly as I didn’t carry out the survey, however I would expect / hope of some indication of there being a false fix by either means of FLOAT position, or just high RMS errors at least but these shots show good results on all of these.
Obviously, I would rather my fix drop out or show high RMS errors so I can exclude these back in the office at least
I agree, something definitely should have happened. Did they pay attention to the RMS? Do they have fixed only shooting turned off? I have seen the status hang and report fixed when it was not and vice versa reporting single when it was fixed. A reboot of the app fixed it but there may be a bug. Running an iPhone 14 Pro here.
