Hey Guys,
Need a brainstorm here.
I'm working in a refinery, for this particular survey, I'm shooting pipe flanges reflectorlessly (spelling :S) . Unfortunatly Im on the top floor of a building and the floor is vibrating with reasonable movement.
Using leica 1200, the compensator is going nuts at me, after a few checks I decide the accuracy of this survey is going to be blown out to maybe 10mm ??
Has any body had expeiriance in this area, do vibration dampner pads for under the legs of the tripod exsist ? I'm really trying to open a brain storm for possible ways/materials that I can put under the legs, that won't slip, but absorb some vibration ?
o.O
Wrestling mat?
Extra info, floor is grid mesh?
If you guys need more info just ask and all ideas are greatly appreciated.
-> Holy Cow,
Thats a good idea, I know I can get magnetic feet holders I wonder if they be powerful enough to hold the mat down to prevent movement.
Anything has got to be better than what I'm doing !
Trickiest job for me was setting up over the peak of a roof on a roughly 100 year-old lumberyard building to shoot nearby roofs for elevation. Switching weight from one foot to the other was enough to throw it off. Imagine trying to get the gun level while not being able to move. Fortunately, the roof was close to flat so there was no slippage problem with the tripod legs. It was a matter of remaining as still as possible for about 45 minutes while adjusting to various locations and relative elevations.
The closest I got to something like that was setup about 20' from an active rail line. All we could figure out to do was check the backsight after every train going by. It was kind of muddy so I had to re-setup about a dozen times that day. At least we had the where with all to keep checking the backsight.
Unfortunatly I had to live with the compensator spitting chips at me, I'll be doing a little research to see what I can find. Good news is - Just compared the pipes measurements to design and it's tight to 0.5mm 😀 😀
some instruments allow you to turn off the compensator
Turn off the compensators. Check level physically before each shot.
“…it's tight to 0.5mm…”
That would be quite a good trick considering that is more accurate than the tech sheet in the Leica TPS 1200 brochure
“…Accuracy / Measurement time Reflectorless < 500 m: 2 mm + 2 ppm / typ. 3 – 6 s, max. 12 s…”
“…Thats a good idea, I know I can get magnetic feet holders I wonder if they be powerful enough to hold the mat down to prevent movement…”
That would be quite another good trick. How do you expect that a mat placed on something that is moving to stop the moving? It will only dampen your sensory perception of the movement.
You could look at different setup locations or use a Laser Scanner that would take so many shots so quickly that you could mean out the data. A total station CANNOT reasonably compete with a laser scanner in these circumstances.
A long time ago I purchased a bracket that attaches? to the vertical steel column. "Look ma no legs". Had limited turning abilities -270 degrees. It was made for laser or rotating levels. Used it to set FF marks on col's with no decking at time and also located a few overhead crane rail tracks in a steel fabricating facility. Crane was going off track and we had to re-align.
Good Luck
Steve
Somewhere on here there is a thread about doing monster high rise layout where someone posted a link to a powerpoint presentation by Leica about doing layout for the tallest building in Dubai and others around the world.
It outlines first how they use GPS but also how to operate a instrument in a environment that can not be level. If I recall they turn off the compensator and measure everything in 2 faces but there is more to it I bet.
Funny little presentation, I looked for it but could not find it. It was in a response in a Scott Zelenak thread from about a year ago if memory serves.
If it is just the floor vibrating and not the wall then a bracket would work for sure. Is it that the floor is not solid or that there is some machinery rocking about?
> “…it's tight to 0.5mm…”
>
> That would be quite a good trick considering that is more accurate than the tech sheet in the Leica TPS 1200 brochure
>
> “…Accuracy / Measurement time Reflectorless < 500 m: 2 mm + 2 ppm / typ. 3 – 6 s, max. 12 s…”
>
>
>
> “…Thats a good idea, I know I can get magnetic feet holders I wonder if they be powerful enough to hold the mat down to prevent movement…”
>
> That would be quite another good trick. How do you expect that a mat placed on something that is moving to stop the moving? It will only dampen your sensory perception of the movement.
>
>
> You could look at different setup locations or use a Laser Scanner that would take so many shots so quickly that you could mean out the data. A total station CANNOT reasonably compete with a laser scanner in these circumstances.
:good: :good:
...That would be quite a good trick considering that is more accurate than the tech sheet in the Leica TPS 1200 brochure
“…Accuracy / Measurement time Reflectorless < 500 m: 2 mm + 2 ppm / typ. 3 – 6 s, max. 12 s…”...
2mm over 500m. ... in the brochure.
All my shots were within 10m of the setup.
“...That would be quite another good trick. How do you expect that a mat placed on something that is moving to stop the moving? It will only dampen your sensory perception of the movement...”
I'm not as worried about total movement because everything 4 stories up moves together, its the uneven rises coming from the legs that are throwing the level out. If I can dampen those, I'll be alot happier. Like I said anything is better than what I was doing.
...You could look at different setup locations or use a Laser Scanner that would take so many shots so quickly that you could mean out the data. A total station CANNOT reasonably compete with a laser scanner in these circumstances....
I left the laser scanner in the office, I was only surveying 6 flanges, an hour of work tops due to vibration. I could have used the scanner and surveyed a 5mm grid at 10 meters. Then spent A full day in the office trying to proccess a 6gb file as opposed to another hour in the office working with a dwg on autocad... .. Didn;t matter where I setup, the whole floor was shaking
"...2mm over 500m. ... in the brochure.
All my shots were within 10m of the setup..."
That means
Your 500m shots have +/-2mm error +/-2ppm or .1 mm for a total of +/-2.1 mm
Your 50m shots have +/-2mm error +/-2ppm or .01 mm for a total of +/-2.01 mm
Your 10m shots have +/-2mm error +/-2ppm or .002 mm for a total of +/-2.002 mm
Your 5m shots have +/-2mm error +/-2ppm or .001 mm for a total of +/-2.001 mm
wow really?
Thanks for your help and great ideas
It is surveyors that claim that they are better than their equipment, or believe fast is better than accurate, that end up reporting bad data to their clients.
My advise would be to only take on work you are qualified to perform.
> It is surveyors that claim that they are better than their equipment, or believe fast is better than accurate, that end up reporting bad data to their clients.
>
> My advise would be to only take on work you are qualified to perform.
:good: :good: :good:
I meant to comment on this, but when someone shows up under a pseudo-name of "Float" and who's first post is wanting to see pictures of smashed up instruments, I thought twice about it.
Ralph
Thanks for your help too Ralph, your an assest to the engineering community..
I'm just having a look now for the post. Sounds very interesting. I'm already shooting all the shots at a average of 4, but switching into double face is a great idea. Thanks
:good: