You could look at some of your other traverses and see what kind of difference you get in face one vs. face two.?ÿ Are they always the same angle as each other?
I have used many different brand/models of robots over the last 20 years and almost all of them required a D&R to get good results, especially for elevation work. However I bought a Trimble S3 about six years ago and have come to the conclusion that a D&R with this gun does not improve the results over a direct shot. This conclusion was made from a lot of testing and comparison over the last six years and I can find no difference, even on longer shots. I still turn a D&R on some of my longer control shots, just because I feel like I should.
I'm not sure what to attribute this to, but feel it must be the applied /stored collimation. I typically run the gun through the collimation routine at the change of seasons and hardly ever see a change in the stored values, which are also always very small. With robots I've used in the past the values were always much larger and I could run the routine back to back and get different results every time, which never gave me much confidence.
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All that being said, check your rod and tripod. Winter time temps always seems to loosen my tripod head screws.
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Sounds like you've got a good one!
I do 4 sets' doesn't take very long because it's automatic.
You use Leica I believe Dave? Do you use measure sets application?
It could be a bit more streamlined. I see a Traverse application but have never used it. I wonder if it allow multiple sets and how streamlined the process is.
I seem to remember the Trimble would turn to a known point in "Measure topo". So if you just had 2 or 3 points it could be quicker than configuring measure sets/rounds application.
We use Trimble S7 with Access.
i did have a 1203 with TDS Ranger but that was 5 or 6 years ago when we switched?ÿ
Our Terrestrial scanners are Leica instruments. (C10 and a P40)
At 100' +/- you should be able to do better than a 1mm pointing with a 30x power scope. But then i'm not sure where that published 1mm in the specs, actually resides.?ÿ
The Traverse application is very nice, when you shoot sets you can assign number of sets, prism type, ATR on/off etc to each FS and it will auto point and remember the settings, if ATR on it will shoot if off you fine sight and shoot and it turns to the next.?ÿ
I don't see how centering the instrument and/target over the nail can be an issue for all the stations for getting good traverse accuracy. Say you have a 5 station closed loop traverse. Your first setup is over SNT2, backsighting STN1 and foresighting STN3. You go round leapfrogging the gear. For stations STN3, STN4 andSTN5 it wouldn't matter if you weren't set over the nail. Accurately centering over the nail would only be important for the first backsight (SNT1) and first station (STN2) setup positions as the gear gets removed and must be accurately placed back over the nail. STN1 will be the last set over station and STN 2 will become a foresight for it.
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The assumption with centering over a point is that upon occupation any error in the tripod/tribrach is assessed and corrected for, if you are leapfrogging the glass and gun through the tribrachs without correcting that is a special approach called forced centering.?ÿ People often have strong feelings one way or the other about which is the appropriate approach.
The other centering brought up earlier in the thread is the centering error in the prism itself, nothing is pure, there is error in the prism grinding and machining of the mechanical assembly that houses it, the adapter and the tribrachs are also not perfect.?ÿ
I do 4 sets' doesn't take very long because it's automatic.
You use Leica I believe Dave? Do you use measure sets application?
It could be a bit more streamlined. I see a Traverse application but have never used it. I wonder if it allow multiple sets and how streamlined the process is.
I seem to remember the Trimble would turn to a known point in "Measure topo". So if you just had 2 or 3 points it could be quicker than configuring measure sets/rounds application.
Squowse,
The traverse routine is very limiting as I recall.?ÿ While it does reduce the traverse in the field you have to work in a very specific workflow.?ÿ Control needs to be occupied in order and while you can have side ties to stub control or monuments, you can not have cross ties to other point in a traverse.?ÿ I have found that the sets of angles routine is a better bang for the buck in my network oriented work flow.
At 100' +/- you should be able to do better than a 1mm pointing with a 30x power scope. But then i'm not sure where that published 1mm in the specs, actually resides.?ÿ
The 1mm is the centering error for what I would assume is manufacturing.?ÿ Growing up in around foundries and manufactures in my family's business I would say 0.0033 feet (a little over 1/32") is pretty tight for mass production.?ÿ For the standard circular prism you are looking at 3 parts.?ÿ If you require tighter specs you can pay out around 2K and get the GHP1P with its .3mm centering error.
In the traverse application you can cross ties or whatever you like. You may need to open another traverse, rather than running all the data in one but that is okay with me. I have not used the sets routine and all my experience is with Smartworx so things may be clunkier in more recent iterations.
One thing it does not do is provide the opportunity to adjust the occupation elevation using the BS vertical observation, which would be nice but is easy enough to do by hand.?ÿ
Hi guys
I have a 3 second Trimble S7.......I read in the manual that when the machine is auto-calibrated any errors in vertical and horizontal collimation and trunion axis are taken into account in the calibration and "adjusted out" and so won't affect the accuracy of measurements if only done in one face.
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Allow me to take another crack at communicating my meaning ...
The 3 second spec of your gun is for a single pointing. So, when your instrument is perfectly collimated you should get 3 second accuracy in your pointings?ÿ (notwithstanding the many other sources of error present in the system) without doubling and averaging ,etc.?ÿ Because that is how the precision spec is defined. So that statement in the manual is true.?ÿ
What the manual doesn't say is that the averaging?ÿ multiple FR/FL readings gets you better and better angles. Up to a point, in practice.?ÿ And it tends to moderate the effects of some other sources of error in the system.?ÿ So you still want to do the doubling for best results.
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Thanks Mark for the explanation
Hi,
Keep in mind that a calibration in the field does not compensate for tripod torsion.. even if direct/reverse shots are being taken.
S0 having a robotic instrument.. I assume you're using a heavyweight wooden tripod which according to ISO12858 can still have a maximum residual torsion of 3".
(And on lightweight wooden tripod this can even be 10"..)
So if you perform a calibration, make sure to do this on a concrete base to make sure no tripod torsion is in there.
You would still have tripod torsion in the field.. but at least this torsion will not be in the calibration values...
Greetz,
Floris.
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