Height discrepancy between laser beam and prism
Lately was asked about DiNi and robot height difference in this forum. I am having similar problem, but between the laser beam and mini prism/360 degree prism using the same instrument – Leica TS16. Target is a sticker on the wall.
What I exactly did…
I oriented my total station using the pole (height 2.0m – I remeasured it with tape measure) and 360 degree prism. Points were on the ground. I controlled the height after orientation. Everything was perfect. Then I measured the wall targets. After that, I decided to use the mini prism to do the rough control (didn’t look for the millimeter) for my wall targets. I checked the mini prism height on the point what I used for the orientation. The height difference what I got was 2 cm for the wall target which was ~40m away. The wall target which was ~150m from the total station showed 4cm difference when I did the laser beam vs mini prism check. I had one more point ~160m away from the total station showing the difference 2 cm. So, I wouldn’t say the further the worse.
I did the adjustment for the total station, still getting these results.
Any ideas? Experience? I know that using different methods – prisms and laser can give some difference, but 2-4cm is a lot. Is it possible to get so big difference with laser beam between two targets. When transferring height from one target to another in one stand. I did put the total station cross in the center of the target manually. Should I just stop doing the control with prism as it’s incorrect?
Work gives interesting research ideas every now and then 🙂
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