6. Make sure your instruments tripod is of high quality and all fasteners are tight.
IMHO (which is 100% correct), this is #1. Every single messed up traverse I have dealt with was traced to poor support for the instrument.
Also, field checking bubbles and targeting for tribrachs is easy if you use a pass through tribrach with a total station with a plummet and carriers with a bubble and plummet for the prisms.
I like that. It’s like having a Cadillac riding on bad tires and warped rims. No matter how accurate and precise an instrument is if what it’s setting on is junk it’s all for nothing.
While I agree that a stable tripod is critical for high precision measurement I kind of object to the use of the word "tight". Because it tends to lead to "overtight". Which makes things wear out quickly . I encourage my guys to tighten these things using their fingertips only. Those screws need to be snug, but not tight.
"Fingertip tight."
That's how I was taught and I'm regularly surprised that others (apparently) didn't receive the same lesson.
The to tight and the not tight enough. I was taught when adjusting tripods that you should be able to pick it up parallel with ground and it’s slowly fall back down nice and smooth. The leg that is. To tight it just hangs in the air to lose it falls rapidly. Of course that was using all wood back then.
Speaking of to tight some like to white knuckle tighten the instrument or target down. That leads to warping the head of the tripod. Plus makes it a bear to unscrew the darn thing. I had one guy he had it torqued Dow so bad once I had to get channel locks to get it undone.
Yeah, over tightening is one of the first things I teach an apprentice when showing them how to take care of the equipment. Another big one is to always put the equipment in their cases when moving between setups. Also, is this all 360 prisms? I’ve had good luck with some as long is you have a flat face to the TS when setting the BS or shooting in a control point. The vertical is what I usually have issue with but running levels to tighten up the vertical seems to correct that.
Ditch the bi-pod. If you are truly worried about accuracy of your control, then utilize stable back sites and fore sites. And that is not a bi-pod, especially since most just rattle around in the back of the truck. Besides, using tri-pods is actually quicker, you need to set one on every point anyway, why not do it to begin with.
As tribraches and prism carriers, I'll second or fourth the recommendation carriers with the integrated plumet. It is easy in the field to determine if they are in adjustment, and just as easy to adjust. They cost about $200 more but the difference is almost made up for in the cost of the tribrach. The extra couple of bucks is well worth it.
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It's nice to work in the big country where never a traverse is heard.
I don't double all of my observations with the (expressed) intention of cancelling out any systematic error in the plummets/poles. My intent is to add redundancy. While the additional observations are done the same day, so they don't have different meteorological conditions, by resetting the tribrachs/poles they are, to some extent, independent measurements. My goal is to introduce random error so that it can then adjusted out (if that makes any sense).
I stumbled upon this practice by accident when I was in school and doing a StarNet pre-analysis on our second-year field project, a large control traverse. By copying and pasting another set of our planned observations into StarNet I saw a dramatic improvement in the confidence of our points, however this is only true, in my opinion, if all targets/instruments are reset to make the observations independent. I have been using this practice for my control ever since.
On a related note, when I am coming off of primary control, with a resection for example, if I have time, I will perform the observations twice (with targets/instrument rotated in between), the mean of the two observations is the MPV (Most Probable Value).