Hello everyone,
We have an issue where I cannot figure out how to troubleshoot or where to look to try and find the source of the issue(s).
We have 2 sets of pickups Day 1 and Day 2. Day 1 and Day 2 had the base setup over a different location. We typically lay a point out near/next to the base location to do some sanity checks, and we also pick up the point as the first point, and also the last point of the day. We always convert these to a UTM system.
On day 2, we also re-picked up 3 points from Day 1 to tie into and check against (we will call them A1,A2, B1, B2, C1, C2)This is where the troubles come in…
Day 1 and Day 2, the first and last point of the respective day line up within a couple of mm yay!
I am making the assumption that Day 1 is the one that I want to be the “truth” and Day 2 is the one that we want to adjust to line up with Day 1. I extract the 3 point from Day 1 and Day 2 to do a comparison against. Normally, when I do a different between all of the, the average of the difference is pretty good.
i.e. normally it looks something like this:
Northing: | Easting: | Elevation: |
---|---|---|
A1 - A1 = 0.456 | A1 - A2 = 1.060 | A1 - A2 = 2.560 |
B1 - B2 = 0.487 | B1 - B2 = 1.070 | B1 - B2 = 2.530 |
C1 - C2 = 0.446 | C1 - C2 = 1.050 | B1 - B2 = 2.550 |
So it is all pretty tight, consistent and I can easily do the adjustments and away we go. But this time, I got some pretty wacky numbers. More like this:
Northing: | Easting: | Elevation: |
---|---|---|
A1 - A1 = 0.326 | A1 - A2 = 0.956 | A1 - A2 = 1.560 |
B1 - B2 = 0.887 | B1 - B2 = 0.070 | B1 - B2 = 0.530 |
C1 - C2 = 0.946 | C1 - C2 = 0.578 | B1 - B2 = 0.250 |
I have also tried to post process to see if any of the results are different, the following are the main things I have tried:
Processing forwards, backwards, combined
Base station with position in header, average single position.
So, if you got these sorts of results, where would you start to look?