We are monitoring a tower on a dam site under construction.?ÿ
Const company wants it all done Robotically. We have two Carlson CR2S and one Leica TS12 5" robots. One CR2 calibrated end of jan, Leica end of Nov 19.
When reading BS about 1170' away thru set and read angle direct and reverse report our residuals are very consistent and good. If we switch over to Stake screen and reshoot to store a coordinate our residuals Direct and Reverse vary 10"-15" almost every time.
When shooting targets permanently attached to tower we are having similar issues on cool cloudy days. Where our coordinates vary from a few thousandths to 3-4 hundredths.?ÿ?ÿ
Making the same measurements and seeing the same results with different instruments on different days with different personel are leading me to believe this is a software issue. Any help would be appreciated. Carlson can't seem to give us a good answer on why. We have performed field calibrations with good results. Thank you?ÿ
It could be the change in temperature, I have talked to people who work on cell phone towers and they tell me that a monopole tower will tract the sun like a sunflower.
Ed
tracttrack the sun like a sunflower.
Probably opposite of a sunflower.?ÿ Heating on the sunlit side will expand the tower on that side and push the top away from the sun, whereas a sunflower follows the sun.
Const company wants it all done Robotically.
Why do they care about methods??ÿ They should be asking for results (i.e., certification of accuracy) and let you pick the methods.
Stopped with Carlson about a year ago, but my memory is that Stake D&R isnt exactly the same as turning Sets D&R.
The best practices are to turn sets to the points that you want to monitor. This is very quick and easy with a robot in Carlson SurvCE, and you could turn 4 sets in not much more time than you turned 1.?ÿ
You could even do all the points at once.
Well, all I know is when I was using Carlson with a Topcon robot I would set a pin, leave the rod on the pin with a bi-pod, STAKE OUT the point I just stored without touching a single thing and it would still read off .03-.05-- and I was nowhere near 1100 feet away.?ÿ It would do this even after performing a field calibration (and later a formal tune-up at a shop), so maybe at some point you just have to acknowledge that maybe the equipment isn't that good...
Temperature will no doubt have an effect on a tower. I would note temperature with every report.
Additionally I'd want to use the same equipment and crew for this task.
My conclusion would be opposite. Software won't change but minor differences in technique and equipment could provide varying results.
Run the calculations (with your scientific calculator) being sure to apply c&r. - you should get same values for both storing and staking in Carlson.?ÿ Record and compare the calculations for both store and stake.
To add to the temperature mentioned above,?ÿ not sure where you are taking the readings on the tower or if the tower is steel.?ÿ If steel or some other metal?ÿ that expands and contracts with temperature, then the tower could also change relative to the expansion coefficient.?ÿ
You did not say if the coordinate value variation was horizontal or vertical.
then there is the trusted trig table book together with old Monroe calculator.?ÿ?ÿ
Raw data should show some signs of the difference.
Before you blame the software you must perform hand calcs from the raw the data.?ÿ
Suggest you rent different equipment. Also try a separate procedure. The best checks in SURVEYING are independent checks with different procedure and equipment.
It's not just steel that moves with the sun. 20 years ago we monitored a tall hotel block which was showing signs of distress - 12 storey concrete, but for some reason the owners had thought it looked good with a full coat of BLACK paint. It was twisting badly as the sun moved round and the concrete spalled off under the repetitive cycling of stresses. Eventually a number of floors had to be taken out of use and a strengthening steel frame put in (it was the middle of a town centre so demolition would have caused great problems) - and it was fully shot blasted and repainted white.
During the monitoring we had magnetic thermometers attached to various parts of bare steel, some in sunlight, some in fully shaded areas, so as to get a record of the temperature gradients.
You could get some idea of twisting if you can leave a couple of instruments set up all day aimed at one point. If each has an RO almost on line at ground level, so as to check that the instrument isn't moving, any changes in the readings during the day would confirm that movement was occurring and that it wasn't software causing the problem. If it is an effect of the sun then the movement will be cyclical and the readings will return to the same position for each morning.
Then you need to decide how to allow for that cyclic movement!
For a task such as this (monitoring steel) i personally would never rely on robotic target recognition.
Also if your processing this in Carlson on the pc end I strongly suggest that you use the direct/reverse report function under tools.
You may be surprised to see that some of your d/r angles aren't reducing properly.
Depending on your field data collection procedures.?ÿ
At some pt I would like to start a thread on carlson survce users field procedures for set collection.