My question is when I set up my Leica TS07 in the morning using a wood/fiberglass quality tripod made for total station use. As the sun is rising the TS starts moving out of level (in the black not red)
Do I re-adjust to the level on the fly and continue to shoot? Leave it in the black and shoot?
Or whenever I make adjustments to the tri-brack do I need to re-shoot my backsight?
Just looking for the best means and methods for re-leveling the TS.
Thank you
If you touch the tribrach then you need to reshoot the back site. You can let the compensator take care of anything in the black if you like. I prefer to keep my back site up and check in on a regular basis.
As for the underlying cause, I would check your tripods for tightness. This time of year, I doubt the legs are sinking into the A/C, even in Las Vegas. Fiberglass tripods tend to be more susceptible changes in conditions than good quality wood legs.
Thank you for your reply!
The tripod is part fiberglass and wood, and it has two locking mechanisms per leg. Just see slight movement when it is sitting still (staying in the black), I feel it's due to temps and sun beating on it. It was recently calibrated. It is a Leica TS07 manual station, and I'm getting a TS16 robotic with an AP20 smart pole next week. Super excited to get it and just trying to make sure my methods are dialed in. I will leave the backsight set up and check in every 5 shots or so as you suggested.
I would check all of the nuts and bolts on tripod, not just the clamps. I doubt it is the instrument. The ones that connect the legs to the head are quite important, especially with robotic instruments, and often neglected. I'm guessing a lot of what you are seeing is with the design and materials of the tripods. I stopped using Tri-Max for anything other than GNSS or radios, years ago because was constantly out on back site checks as the weather changed. The coefficient of expansion plays a lot into the issue. Not to sound like a salesman but the Leica GS120-9 legs. The Tri-Max work well if the conditions are constant.
As for back site checks, I think every five shots is a little overkill, once you have the leg issue resolved. I usually check in every 30 minutes or so for topo and construction. More often for critical work.
As for the AP20, I love mine. I'm currently working on a project that would require about 3 times the effort if I had to do it with the pole vertical.
Thanks again, Sir!
What surface are you setting up on? Here in Australia the bitumen becomes very soft during a hot day and the tripod legs start sinking in quite quickly. Maybe consider setting up on a different surface or drive something into the ground to make it more stable, like a wooden peg or spike.
Come to think of it, how come I've never seen like a setup assist peg or wedge that you can drive into soft surfaces to help you setup on soft surfaces like sand or loose dirt?
Composition materials like you describe (Trimax?) have a very high coefficient of thermal expansion. All wood tripods are better for that.
Depending on the age of your tripod those rubber grommets between the tripod top plate and bottom as well as where legs attach. They start going bad and temp changes can play havoc on them. I would also check the tribrach itself to make sure those foot screws and such are not getting loose or a bad spring on one of them. If you do as mentioned above and snug the bolts up and check later and it’s loosening up that is an indicator your rubber gaskets are bad or are going bad. A quick temp fix is to rub a little oil on them and put back together. They can dry rot over time and get brittle.
I'm setting up on hard desert land. Full weight 200 pounds stepping on leg pegs with a little bounce on it to push it in the desert. The tripod is Mountlaser brand and I attached a couple of online photos since the tripod is at work. Tomorrow I will check all the nuts and screws, it is a new tripod. The tripod is heavy about 20 pounds
It has a copper 5/8" screw for the TS tribrack.
https://www.amazon.com/Fiberglass-Surveying-Robotic-Stations-Theodolite/dp/B0B362G15C
There is a Leica Dealer in town, I can get the GS120-9, just have to convince the Project Manager to justify the purchase. I did finally convince them to get a TS16 Robotic, so it should not be too hard...
Leica GST 120-9 is an excellent choice.
Sounds like it's your tripod and not the ground. Also, if your backsight is on a tripod it can be moving. Probably not as big a deal, but you might want a second check Angle sight.
If all hardware is tight, the legs may be popping out as not enough downward weight.
Sandbags?
Surprised with that new setup INVESTMENT $$$$$$$, nobody talked the sales rep to throw the good Leica tripod in with the deal. Otherwise buy elsewhere if not.
Yes, the TS16 negotiations were done without my involvement, The Tripod I have now was bought by the supervisor stating high quality, I could only find it on Amazon. Not saying it is a bad tripod, it feels good legs seem to be of wood and the rest is fiberglass with a nice metal polished big round flat head.
I will check all the nuts and screws and go from there, if I see no improvement, I will ask to get the Leica one. And yes I do use sandbags at its feet. There could be a loose screw by the head or foot not sure, but when setting up it felt solid.
Are you pulling your instrument straight out of the case and getting surveying.
In the past I have found it can be worthwhile to let the instrument and legs acclimatise for ten or fifteen minutes before trying to do any really high accuracy work.
yeah, straight to work, this time of year in Vegas the morning temps could be 35 degrees, and afternoon like 65 70 degrees. But I'm not usually out all day, just the temps are constantly moving up.
Also, the machine and legs are in a warm trailer, pull the gear out into the cold etc...
A lot of factors going on here...............
Ideally, set up your tripod about 20 minutes before backsighting. That will give the stresses time to equalize. In practice that means checking and resetting your BS after that amount of time. Thereafter it will stay "on" for quite a long while if undisturbed.
Composite tripods are really popular here in the PNW where we work in the rain - a lot. I prefer the Leica 120-9s even so, and if I was working in the desert that would be x100.
Check out the white paper here:
https://leica-geosystems.com/en-us/products/levels/accessories/tripods
With a Total Station or and/or Robotic TS, if you re-level or make any adjustment at-all to your setup, you MUST recheck your back site. I would also mention to; re-zero, but that is no longer applicable to many modern instruments. Also be aware and determine if your instrumentation accounts for PPM adjustments, this has nothing to do with the instrument being level but it is important if your environmental temperature has changed significantly since you initially started collecting data. Someone already mentioned your back-site setup as well; never tear-down without checking and insuring your back-site setup is still plumb.
I am very familiar with the unique range of daily temperatures that can occur rapidly in southern NV . Also be aware that an instrument can still be level but if one side is constantly exposed to the sun more that the other, it will definitely influence any bubble level indicators. During your initial instrument setup, ensure you rotate the ‘gun’ after the initial leveling to ensure it looks good in all quadrants. Also no matter what tripod you use, slap the legs a few times to ensure nothing is pinching and any stress is relieved before being satisfied with your setup.
Many moons have passed since I last worked on a two man crew and a Total Station. That being said, I recall taking a ‘natural’ site on some disguisable far away object (maybe the Stratosphere Casino Tower) in the general direction the ‘gun’ is pointing at for a quick check by the Instrument Operator without having to keep turning to the back-site. At the end of the setup however the IO should shoot and record the last BS reading.
