Prism Constants!
Something that I have had to address lately. The importance of understanding what a prism constant is. When and how to use this when mixing different manufacturers total stations or robots and even different prisms. We are pretty much a Trimble shop. So running the S 5 with the MT1000 and the Trimble Traverse kits of -35mm. We have crews in different states that do not have these and have an assortment of topcon, seco and other brands of prisms. The standard is for them to set all prisms at the 0mm offset for traversing. In most casesI have no issues but my crews don’t have that option. It causes issues when we go to a different state and things like true height vs S knotch and the -35mm pops up for someone else to QA/QC. I remember running the old stack prisms triples singles and wild prisms seco etc. We had sokkia total stations wild and topcon. A hodgepodge that we all had to understand where to place the prism constant for each piece of equipment. Sometimes that meant in the total station itself sometimes in the data collector. Sometimes we had to do math like -34.4mm for a leica was set to 0.
How does everyone else operate these days. Whats your preferred set up for traverse kits. I can remember taking a BS to a plumb bob string then stacking a natural (range pole, stake with a tack. Shiner in a tree etc.) then I would haul rump to FS while i held a pole and single prism while I man turned sets rounds. Yes BS was angles only except first distance back. Times have changed equipment has and now I can just choose the pre programmed target prism type and all the thinking is done for me. But when something changes or someone does something a little different the issue arises.
Thought this would be a place to share some wisdom for the younger folks to have for both in the field and in office . Standards are great but often can lead overtime to issues because it’s always been that way
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