Rolling prism pole

I think someone (SECO maybe?) sells a wheel for the bottom of the pole, but that wouldn't help with plumbing the pole.

Can the prism be low, close to the floor? You could mount it on some sort of cart or wagon and tow it around - just stop and take a shot.

Or mount it on one of those remote controlled cars!

How about this
http://themarksman.ca/products/rod-point-unit

Are you overthinking this a bit. A mini prism, small pole, piece of string ties to the top, walk along and lower like a plumbob over the points - if it's just for level slightly off plumb or off point wont have a significant effect if your tolerance is 2 or 3mm - that's the tolerance of the prism anyway

Why not just shoot it reflectorlessly?

If production is the priority, maybe you don't need to be perfectly plumb, so maybe a gimbal setup is not needed. At a 1.500m prism height you can be out of plumb 55mm and still be within 1mm of the 1.500m.
You wouldn't want to be dragging the prism pole point from station to station. Maybe a 3 wheel cart with the prism pole suspended by light springs would work. Roll it to position, weight the prism a little bit so the point contacts the floor, shoot it, and move on.
I hope you're a better fabricator than drawer of designs 🙂

Someone I worked with took the top off an office chair and mounted the pole on the base. He used this for levels along a road so not quite the same accuracy as you require but it sure did make it easy just to push this unit along the road and pause to take a reading as required.

The rod point unit linked above looks slick, but there is also this:
http://surveying.com/Products/Instrument-Tripod-Accessories/Tripod-Stability/90555

Combined with a mini tripod this seems like what you're looking for.

Also, I know Doug at Pacific Survey Supply in Medford, OR builds one similar to the SECO version. You could try giving him a call at (541) 772-5777.

What about this, a coupe washers and a 5/8 nut or bolt depending on your pole tip.

http://m.harborfreight.com/3-wheel-steel-dolly-62706.html

If you had a small tripod as shown in original sketch on good set of castors with a target mounted on top then theoretically that should be at a constant height above the floor.
This would be the same as taking shots on a pole.
Any small deviations in the surface are only located if you place the pole at that precise spot.
I'd imagine a series of measurements would yield accurate results.
Obviously edges of a slab would need measuring with a pole or similar.

Other option and one I'm in favour of, is a piece of reflective tape applied to a 30 - 40 mm right angle aluminum section placed right on the concrete.
No plumbing woes whatsoever.

Thanks Richard so lets assume I do a floor of 80m x 60m then I could just stick my ball prism (trimble), which I still need te confirm the constant, on my rigid suspension RC car and take shots. I usually do shots at 1m intervals so if it were sloping the Height target should remain ok? I mean the data is used for checking if puddling would occur etc. Dont do it all that much but would.to try it out if I get a chance.

Seeing as I've got all this knowledge on the forum, anyone knoe the prism.constant on the SECO 50mm ball prism? Bought it when the Leica Laser trackers ball got damaged to see if it could work but didn't so put it in the S6 toolbox,but using in anything other than bolt holes yield strange results. Faces create a problem

Thanks guys

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I would venture to guess that the prism ball has a 0 offset for prism constant. Not positive, but that would be my guess. Easy enough to test of course.

Well I also firstly assumed it should be 0 as that is what the leica sphericals for the laser tracker are but quickly saw it wasnt,and also not noted on the packaging. Did some tests and determined it should be -17 but that then only works for when the prism is in some hole. Found a german reseller last yrar that was the only site to note a prism constant and was also marked as -17. So I am confident the prism constant is correct at -17 but somehow it doesnt work as it should when surveying faces of walls,beams,cylinders etc. Will so some setups tomorrow and post results to ahow what I get. And also start a new thread

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Why don't you just put the prism at the foot of the pole ? the prism height would be less than 100mm off the ground, plumbing errors would be minute.

I have done this with a leica mini prism shooting a race track for ponding issues, worked really well.

A trimble 360 prism has a standard thread on the top, just screw on a topo shoe or boot or a prism point , and go robotic, you could pick up hundreds of shots like that.

I can send you a picture of how we set it up and do this same thing, we do it to shoot astro turf fields at 2m intervals

laser scanner registered to a few precision level points.

Or use something that doesn't need plumbed, like a spherically mounted retro-reflector SMR. They are used with laser trackers. The new ones are expensive (~$2,500). You can probably find a cheap one on ebay.

Or something like this: All Metal Prism Ball Reflector works with Leica, Topcon etc Total Station

Hi Mike. Thats the ideal solution and havr done that more often than not but sometimes the P40 is busy and doesn't justify delaying my site to wait for it. We do have the SMR for the laser tracker. Speaking under immense correction he have the Leica 20 and 40micro sphericals. Bought the 20micron about a year ago (think it was in the range of $6000). The SECO 50mm was bought to see if it would work on the tracker but it wont even lock. Kinda locks and then loses it again. Think that it isnt machined accurately enough.

The setup would be mostly be used for floors and positions only need to about 50mm accurate but heights 3mm. Will just used a magnet holder from the tracker to hold the ball with a pole on the other side and use it on ground level with 25mm height of target. Should work fine and fast enough

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When an SMR no longer works with a laser tracker, we sometimes find they still work with a total staion

I may be a little late to the thread but it seems that if you are looking for 2mm precision that a total station may be lacking a bit. I would say level away.

Gromaticus, post: 373774, member: 597 wrote: I think someone (SECO maybe?) sells a wheel for the bottom of the pole, but that wouldn't help with plumbing the pole.

That would be Loink, and their RTK Rod Wheel .

pdop 1.0, post: 374090, member: 459 wrote: Why don't you just put the prism at the foot of the pole ? the prism height would be less than 100mm off the ground, plumbing errors would be minute.

I am in agreement with this set up, have the mini prism on a small point, then a pole coming from the top to hold it from, the amount it is off level at that short a distance off the floor would be very minor. Might be worth a try at least.