Hi Is any one using the mini prism with rebotic total station and how it's work should I use the bipod if any one know s
I have used a mini prism with my Topcon GPT8005A when laying out very tight tolerances. It worked well, very well.
I will say that on my project, the distance from my instrument to my layout points was never more than 100-125 feet. I was using the mini prism on the holder, and not a prism pole. The points I was laying out were about chest high or so.
> Hi Is any one using the mini prism with rebotic total station and how it's work should I use the bipod if any one know s
I use Leica mini-prisms most of the time with my TCRA1102plus. The pointing error spec is 1mm, and they're small and light. I've gotten excellent results with them.
With all mini prisms it's worth checking them against a quality full size prism. Over the years I've found significant (up to 1/2") variations in the prism constants - even with prisms of the same type.
The only annoying thing about using a mini-prism with a robotic total station is when you place the prism down to hammer in a peg/nail and it looses lock and you have to walk all the way over to the instrument. I'm certain there are ways around this, like turning off search or pausing the tracking but i did not use this too long to be much of an issue.
They work very well with the Trimble robots. Most of the times I use only the prism without holder.(prism const and Target heigt both = 0)
I pay attention where I turn my prisma away from the gun (loose lock), that's where I put the prism back and turn again towards the gun to gain lock again, this has worked very well for me.
Chr.
mini prism with robotic total station
Except for topo, I almost always use a seco mini prism with my robotic S6. There is more potential error in a 360° prism than a regular prism (mainly due to pointing errors and the fact that often none of the prisms in a 360° are pointed directly at the gun. The seco mini can be set at -30 or 0 offset. There is much more error due to misalignment at the 0 mm offset than the -30 mm offset.
Hi Christ,
I don't understand target height = 0. Even without the use of the holder, wouldn't the target height be the distance from the surveyed point to the center of the prism (whatever the external radius of mini prism is, example 1.5-2cm's) as opposed to 0?
mini prism with robotic total station
I think the reason some people prefer 0 offset is to reduce risk of errors with the use of various prisms types and sizes. If I recall, the constant on Trimble 360 prism is +2mm, as you mentioned, Seco's can be selected at 0mm. Wrong prism seleted inadvertently for tight layout? Damage ~2mm instead of somewhere around 3 cm's. You are correct though, a 0 offset does increase pointing error risks.
I used Leica mini prisms myself, I like them, they consistently give reliable returns.
James,
your correct,
but I use the miniprism for points on facades where the height of the point to measure is actually behind the mirror (in the vertical plane) and not the point on the floor. And to place/check nails on wooden stakes when doing construction work, no elevations needed then.
Chr.
