Mathematics?
> ANYWAY, this is a mathematics thread, NOT a land surveying thread.
Well, considering that the science of measurement is central to land surveying, it definitely is more closely related to land surveying than to mathematics.
It's a bit silly to think that land surveying has no connection to the equipment with which measurements are made or to the methods of computation used to produce a number of essential results, including estimates of uncertainty. That would be mortgage surveying you probably have in mind, not land surveying. :>
Similar to the thoughts I posited a few posts above.
> Similar to the thoughts I posited a few posts above.
I'm still puzzling over the period of the error after reading the description of the circle reading system.
I wonder if perhaps I've misunderstood some element of the test procedure. Just to confirm: the target array you measured directions to consisted of more than fifty fixed targets and the directions to them were measured on different parts of the circle by rotating the instrument by reinserting it in the tribrach or by rotating the tribrach and calculating the relative coordinates of the new instrument center by resection?
> I wonder if perhaps I've misunderstood some element of the test procedure. Just to confirm: the target array you measured directions to consisted of more than fifty fixed targets and the directions to them were measured on different parts of the circle by rotating the instrument by reinserting it in the tribrach or by rotating the tribrach and calculating the relative coordinates of the new instrument center by resection?
Yep, once the three tribrach positions were used up I moved the tripod & instrument to a new position in the network and did it again to change the geometry that the instrument saw, and hit new relative positions on the circle, and to try to eliminate effects that might be peculiar to the one setup position.
> Yep, once the three tribrach positions were used up I moved the tripod & instrument to a new position in the network and did it again to change the geometry that the instrument saw, and hit new relative positions on the circle, and to try to eliminate effects that might be peculiar to the one setup position.
But when you rotated the tribrach, you used the resection to determine the coordinates of the new instrument center, right? Over how large a sector of the circle were the targets observed from any setup distributed?
> But when you rotated the tribrach, you used the resection to determine the coordinates of the new instrument center, right? Over how large a sector of the circle were the targets observed from any setup distributed?
Yep, resections for every time the instrument was physically moved in any way. Here is a plot of how the circle 'saw' the network on the last and second setup:
> > TS30 white paper
> >
>
> The key bit may be this on Page 6 of the above report:
>
> "By using two encoders for the angle measurements, the periodic error of the eccentricity of the coded glass circle compared to the standing axis of the total station is eliminated. Another two encoders remove further minor pi-periodic errors which are determined by the system"
Where are the Leica Engineers? Or at least the marketing folks? Is the subject of this thread coming so close to proprietary designs, that their best course of action is to stay mum? I'd think they'd make hay, jumping in, if only to explain why Leica is better than other manufacturers.
Or could it be that Conrad has stumbled on to the secret sauce: SOFTWARE? If all it takes to make a 10" instrument into a 1" instrument is a little "adjustment" to the code, we'll be reading threads about hacking the software!
In any case, I'm just curious why manufacturers don't participate here more than they do (unless some of you are them and we just don't know it.B-)
Hello rfc,
I've been a member at another forum, discussing motor oils of all things, and they have several members from the pointy end of the industry posting. If I remember correctly one may have been a chemist who formulated engine oil additive packages. Some are retired and were directly involved in R&D and are hyper-knowledgeable. Some were current. They also did some big Q&A's with the major oil companies like Castrol and Mobil and the answers they received were predictably anywhere between informative to very guarded. Also predictably the forum responses ranged from grateful to ungrateful.
I think representation from instrument companies could be informative. As long it was an engineer/designer and not your typical marketing/sales person. I've already stated that I'd be happy to learn my ideas don't represent reality because I'd be better off.
Keep trying to learn broski.
rfc, If You Do Not Understand Your Tools,
you do not understand your job.
Paul in PA
rfc, If You Do Not Understand Your Tools,
:good: :good: :good:
> > But when you rotated the tribrach, you used the resection to determine the coordinates of the new instrument center, right? Over how large a sector of the circle were the targets observed from any setup distributed?
>
> Yep, resections for every time the instrument was physically moved in any way. Here is a plot of how the circle 'saw' the network on the last and second setup:
>
>
When you adjusted the observations, were the coordinates of the instrument setup basically recomputed from all of the observations to targets or were just four or five targets used for the resection and the coordinates of the instrument center derived from them (either fixed or with uncertainties) used to adjust the directions?
Not to be argumentative...
but my 5" Total Station doesn't suck...
McMillimeter
Sorry.
Discussions like this always make me think of Keith and what he considered the most critical aspects of land surveying.
Like him or not, he was right about a lot of things.
Not everything, but a lot of things.
Don
McMillimeter
> Like him or not, he was right about a lot of things.
> Not everything, but a lot of things.
What is the most important thing that comes to mind that you think he was correct about?
McMillimeter
> What is the most important thing that comes to mind that you think he was correct about?
I think he usually had his name spelled correctly...
:clap:
McMillimeter
> > What is the most important thing that comes to mind that you think he was correct about?
>
> I think he usually had his name spelled correctly...
And he seemed to be a proficient wood worker, too.
> The key bit may be this on Page 6 of the above report:
>
> "By using two encoders for the angle measurements, the periodic error of the eccentricity of the coded glass circle compared to the standing axis of the total station is eliminated. Another two encoders remove further minor pi-periodic errors which are determined by the system"
There's another clue from this description of the Leica TPS1100 series angle reading system on Pg. 3 of the manual linked below which sounds similar to the 1200 series.
>"Unlike most absolute angle-measuring systems on the market, where the position has to be decoded from several parallel tracks, the circle carries only one graduation track, the code of which continually alters and contains all of the positional information."
What I get out of that is that the graduation track is not uniform, but has some additional pattern from which the coarse reading of angles is made. That may well be the source of the periodic error in the fine reading.
The Leica Patent
And here is what I think is the patent that describes the circle reading system in Conrad's 1200-series instrument:
> ... representation from instrument companies could be informative. As long it was an engineer/designer and not your typical marketing/sales person.....
It would be great to have some of the engineers chime in. But there are a couple of sales reps who contribute here who have been very helpful. Mark Williams, who posts regularly as "surveythemark", comes to mind.
Yeah, neither of my total stations suck either.....
It's pretty funny that the standard instrument of the past, the K&E paragon 20" instrument was pretty good, too.
I reckon it all lies in the output. I had one party chief INSIST on recording his notes in meters because the instrument read to 3 decimal places and when in foot mode only two decimal places.
When I start machine placement then I will worry about my 5 second gun. It's running fine now, 13 sided traverse, 13" of error in the angles and a 1/47,000 closure works for me.
