The thread below got me to thinking...
Instrument: Trimble 5600 series.
When going through the set up procedure, the instrument displays a coarse bubble, After you are satisfied that the instrument is as level as you can get it, the dual axis compensators kick in and measure the axis errors caused by being slightly out of level. These corrections are applied to all of the angles.
Next you enter the fine bubble and finish leveling up the instrument up.
Why wouldn't the compensators measure the out of level condition AFTER you have finished the fine leveling? It almost seems like for high accuracy requirements, robotic instruments would include the axis compensator measurement into the angle measurement process. In other words, it would measure the out of level condition immediately prior to measuring the angles to eliminate errors caused by settling/expanding/contracting tripod legs. Do the newer instruments do this or do they assume you will eliminate some of these errors by measuring in both faces and averaging the angles for high accuracy work?
EDIT: I think I answered my second question. All it would do is make your split smaller, not necessarily improve the accuracy of the averaged angle.
The Trimble S6 does something close to what you're describing, their buzzword for it is Sure Point. Once you set the backsight, if the instrument goes out of level (within the limits of the compensator) it will compensate both the angles and the pointing using data from the tilt sensors. You can set 0 on a point with an S6 and turn the leveling screws - it will still read zero and if you look through the scope it will still be aimed at the target.
Sounds pretty slick!
Another improvement I have envisioned (not related to this question), is that the gun should know when you are parallel to 2 of the tribrac screws. This way when you are leveling up, you are not fighting the bubble. Seems pretty simple. Does the S6 have this as well?
When you go to the level screen on the data collector it displays tilt values for the two axis, but it doesn't know where the screws are or drive itself to any particular orientation.
I guess the way I level a tribrac is to work the screws that are parallel to the front of the instrument together and the opposite screw on it's own. IF the gun is perfectly aligned with the two front screws, you can adjust the two axis's separately, which is a big time saver when you are doing the fine bubble and you have a separate bubble for each axis.
Seems like a simple programming trick.
You Align The Instrument To The Screws, Don' Worry About BS
Level 2 screws, turn 90°, level single screw, turn 90°, check your plummet, adjust if necessary, relevel 2 screws, turn 90°, level single screw, turn 90°, recheck plummet. ZNow you set your backsight.
By walking around the instrument you are also checking for any soft ground spots that may affect the level when you are standing there.
Paul in PA
You Align The Instrument To The Screws, Don' Worry About BS
[sarcasm]Well jeeze, I've only been doing this since the 7th grade. I think I know how to level up an instrument![/sarcasm] It does not take that long. It was just an enhancement idea.
The Trimble has a dual bubble that shows both axis on one screen, so you don't need to be tripping over the tripod legs. I check the legs when I set the tripod up BEFORE it gets leveled. Reminds me of a survey that I helped on years ago. It just looked like sub-irrigated pasture. The cows had it eaten down to the roots. You could jump up and down and feel the ground bobbing around like a boat. Don't know how we were able to traverse across that stuff, but we did.
I would even be happy if there were 2 dots you could line up on the base of the instrument. They don't even have that. I guess I could make it easier by simply making my own dots...No I will just continue doing it as I have.
