While preparing to run a 25 acre boundary last week I accidentally opened the Collimation & Trunnion axis tilt routine on my S7 rather than the Autolock collimation routine that I was looking for.?ÿ I thought that I canceled out before any changes were stored but the busted traverse says otherwise.?ÿ I checked all the rods, prisms, etc over the weekend with no surprises then took the instrument to the shop this week.?ÿ It seems that I managed to put a unnecessary 6" horizontal collimation "correction" into the S7.
We turned three sets forward and reverse with several cross-ties criss-crossing the traverse.?ÿ We ran it clockwise and the bust was a gap rather than an overlap.?ÿ The raw traverse closure was 31"?ÿ horizontal with 17 stations over 5000' with a bust of 0.4'.
I plan to rerun the traverse but I'd like to figure out if there is a way in Trimble Business Center or Carlson to back out a goof like this.?ÿ I've tried Adjust Traverse and Adjust Network in TBC and both insist on tweeking the distances by as much as a tenth. It seems that it should be possible to adjust the angles while leaving the distances alone but I just can't figure out where to the enter the Bonehead Correction Factor.
6" should have shown up as 12" +/- closure error on each set of turns but should have come out in the wash when meaned. 31" in 17 turns is less than 2" a turn, which is within the range of the S7. If you do anything, you use least squares on the network. I would suggest you have someone look at your raw data sets as I doubt it is as bad as you think. 0.4'/5,000 = 1/12,500. You may just have a blunder in one of the setups.
Paul in PA
Mixup of prism and prismless shots.
Mixup of prism and prismless shots.
No, we were mixing prism types (360's and Flats) bet we consistently kept the 360 on foresight?ÿ and the flat glass on the backsight.?ÿ Backsight distances checked within thousandths at every station.?ÿ I trust the distances over the angles on this one.?ÿ
I may be getting mixed up on terminology but a 6" correction on collimation would not have a 6" effect on a shot that had a backsight and foresight that were close to level. Not sure what is meant by "?ÿ?ÿ 6" Horizontal Collimation?ÿ correction ?ÿ?ÿ ".
I know what I think it means, not sure what trimble thinks it means.
James
If you think you have a systematic error in your angles, you can use Carlson's Raw File Editor. Under the Edit pull down menu is the Modify Measurements command.
Should have cancelled out if you were doing both faces. Yku would just see a larger split.
Even if only one face all ha measurements would be equally affected so no effect on the survey??ÿ
I must be missing something?ÿ
?ÿ
I thought the rounds should've cancelled the error as well.?ÿ I wasn't running the instrument so it's possible that the instrument man blundered a couple of setups.
I just had the instrument calibrated and I'll be re-running the traverse alone so I'll find the goofs wherever they are.
One thing I'd?ÿcheck into?ÿis the offset between autolock centering and visually centering on a target. Just a hunch but it might not have anything to do with the collimation at all. A simple three legged traverse using just the passive and then the active prisms might reveal something. What usually gets me in trouble on this type of thing are relatively short backsights and with 17 setups I'd suspect there'd be?ÿa few.
Just because I'm paranoid, doesn't mean they aren't out to get me.
I keep my active prisms set to semi-active for just that reason. Semi-active tracking will track in active mode until you take a shot then switch to passive while taking the shot.
There were two or three places where we had short legs followed by long legs. I may start by re-runnig those legs prior to redoing the entire traverse.