Working on a big site at the moment where the secondary controls (retros) are 100-200 meters away so I took my kit to the annual calibration early to make sure all good. When got the kit back I did the checks and I was not happy... The way I did the check is, that I saved a point on a fixed point/retro, then turned the TS (total station) facing me, then turned the optical vertically 180degrees (upside down), went onto the saved point and layout the point and I got 12-14mm error on 120meters, did the same on another point 70meters away and I got 5mm error. Got the other engineer on site to do the same with his ICR55 (5"!!!) kit and he only got 5mm error on the same 120meters.
I am sure the calibration could be better on my kit, I am getting in touch with the company now who did it, but I thought I ask here if anyone experienced similar before? Also, anyone know about any accuracy the calibration must be done within?
What total station? Typically you can do your own calibration. And your results seem high while the other guys seem reasonable.
In my world "calibration" is a word used when comparing measured distances to a standardized baseline. What you seem to be describing is "collimation". Collimation can be done (almost) anywhere at anytime- it will take maybe 5 minutes. It should be done every few weeks. Check your instrument's manual for specific instructions.
I have found that, once collimated, Trimble and Leica instruments will stay collimated almost indefinitely. Topcons will need to be collimated every few days to perform near specifications.
@norman-oklahoma we use exclusively Leica and check the collimation once a month in addition to having our guns cleaned, calibrated and certified by Leica once a year to be in compliance with State statutes.
we use exclusively Leica and check the collimation once a month
I bet that if you polled all the field crew party chiefs in the country you would find that 80% have never heard of it and 15% have but have never done it and don't know how.
99% of the remaining 5% claim that they do it regularly but haven't in 6 months or more.
So more power to you and your guys.
@norman-oklahoma And then there was a survey crew I had once where distances all seemed to be off, so I had them check the temperature and humidity settings. This was in the summer and the settings were from the past winter.
ps In my practice, solo, I update the settings every hour. Doesn't take a few seconds.
temperature and humidity settings
I thought the order of importance was temperature first, absolute air pressure (not the weatherman's pressure) second, and humidity only if going for extreme accuracy like certifying a CBL.
I thought the order of importance was temperature first, absolute air pressure (not the weatherman's pressure) second, and humidity only if going for extreme accuracy like certifying a CBL.
First and foremost would be prism height and prism constant. Way more f*ck ups (BTW: thats a technical term) over that than anything else.
I thought the order of importance was temperature first, absolute air pressure second, and humidity only if going for extreme accuracy
I'm sure that line of thinking works for Iowa. Pressure doesn't change much with weather - maybe 20 or 30 millibars at most (hurricanes and tornados notwithstanding)- but it does change rather dramatically with altitude. A surveyor in Oregon might be at sea level one day and over 5000', or even more, the next. In such cases the difference in station pressure will approach 200 millibars.
Okay, for some P may be more important. My point was that he left out pressure/altitude..
When I did FDOT projects in the 90s our EFB software demanded a calibration check before we began collecting at the beginning of each day. I believe that in EFB lingo calibration was synonymous with collimation.
Nowadays I use the built in collimation routine in my TS. I also use the National Weather Service to get temperature and pressure for input to my TS. It’s interesting that this input does not appear in raw data.
If he's using the ICR55, that's the Leica ICON construction series TS and software. We have a fleet of those for our carpenters. I've yet to find a collimation routine through the toughpad. We send them off, at the least, yearly. Simple for layout purposes but lack a lot of surveying functionality.
probably like the site wise Trimble stuff, don't let the monkeys running the toys do too much or the big nasty problems will emerge from your under trained under paid overworked staff.
it the American business model.
I do my calibration/collimation routine quarterly or in the event my box gets bumped more than I think it should and make sure everything is hunky dory.
I had a Supervisor once that flipped out when I was running the routine on my 6 mo old SX12, he literally nearly lost his mind....not sure what people believe these things do when they're not looking....only the vendors can do that I was told...I left that place.
use the National Weather Service to get temperature and pressure for input to my TS
In your area that's fine. At higher elevations the reported pressure has to be adjusted for the approximate elevation, to undo the weather people's adjustment to equivalent sea level pressure.
@jitterboogie You hit the nail on the head there! Not sure we would want them doing collimations etc. We're just happy when the equipment comes back to the yard in one piece and not looking like it did 10 rounds with Mike Tyson. And these are very well paid union carpenters that are usually foreman on top of that. They just want their control and layout points so they can get to building.
