Best LS tilt compensation practice

M

Mark Wheeler

Active Member
What is the best method and calibrations to get the most precise position with Tilt Compensation on locations that cannot be done level? There are several calibration routines ( Compass, Level, Level Offset). What frequency do these calibrations need to be done and how much have you found them to improve position?
Mark
 
ken larson

ken larson

Active Member
Compass I do...most often prompted when trying to stake and I am chasing in circles. Helps greatly....should be done on your rod as you would use in field.
 
Adam Plumley

Adam Plumley

Active Member
JAVAD GNSS
Its really easy to check. In the open, take a shot leaning direction then a shot leaning the other way. If everything is calibrated correctly and the rod height is entered correctly they should agree within a tenth or less.
 
M

Mark Wheeler

Active Member
When the snow melted a little I carefully did all three calibrations. As Adam said, a steadied tipped rod location showed all less than a tenth. I tried the method John suggested of leaving the rod in the same tilt direction, and rotating the LS facing direction 90 degrees every 30 seconds (4 directions = 120 seconds). The location point was 0.02' from the level shot.
I previously would do the level offset calibration on the pole frequently, but only did the Level and Compass corrections a couple times a year. This time I went out in a an open area with no interference and used a level. Still found it a little warbly doing the compass calibration, but the results were much better than I was used to. Also, I typically did the Levels calibration on the dining room table, which was stable and level versus away from forces that could interfere with the calibration. Thanks for the advice.
Mark
 
M

Mark Wheeler

Active Member
Not so good Nate. I think John's approach of rotating the LS at equal intervals throught the collection should help, but there is so much multipathing near a building and blocked out view to the sat field that I would not rely too much on the shot. I may take the building corner shot, but also do an offset intersection or range line the building where we can get sky. Metal issue is what it is.
Mark
 
Nate The Surveyor

Nate The Surveyor

Well-Known Member
Blunt truth. Tilt uses magnetic direction.
I recently needed to stake a corner, (search for old R/R spike) in, on, near a cattle guard. The Left-Right, Foreward-Back was useless. Strictly use CTT, and DTT. Because the cattle guard threw the compass off too much. So, since my H/T (Height of Target), all the way down is 5.1', I just use 5' offset, measured with my prism pole. I don't use the tilt feature. Because where I NEED it, is in a fence. Usually, there is a fence brace there, made from lots of wire, or a big metal pipe.
I will share a trick.

You have a monument under a fence brace. Set your pole plumb, but not on the monument. Then measure to the monument, near the ground. Then, stand up, and measure to a point on the fence brace. Check direction. Then, remove the LS from the pole, and place it manually, on the temporary mark, an the cross member.
Now you have it pretty good.
Nate
 
C

Csk21

New Member
So this might be a dumb question...I typically do mostly boundary work and don't usually worry about doing a measure up on the T-3 base. I'll set up the base at a random location (fence post, top of truck cap, tripod if needed) and set control in order to use the shift function later if a return trip is needed or to set corners.

I'd like to start using the tilt corrections for shooting building corners that are not going to be dimensioned to the property lines.

I understand that the rod height needs to be correct in order to correct for tilts but does it matter that I'm not measuring the base height?

Thanks in advance.
 
You must log in or register to reply here.
Top