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Network Adjustment Work on field
Posted by DanielJ on July 24, 2023 at 8:03 amHi folks,
Does anyone have or know where to find a general manual, protocol or report for field work procedure that is needed for network adjustment measurements.
Much appreciated.
Norman_Oklahoma replied 1 year, 1 month ago 6 Members · 12 Replies -
12 Replies
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What are the accuracies needed and what equipment will the network be established with? Those 2 answers will have a major impact on necessary procedures.
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As usual, I find myself reading the OP differently. To me, he seems interested in network design rather than adjustments in general.
With that in mind, I suggest the following books:
Dr. Shanlong Kuang’s text is out-of-print but may be available from resellers.
https://link.springer.com/book/10.1007/978-3-642-70659-2
On the general issues related to standards and specifications (pre-GPS) see: https://www.ngs.noaa.gov/FGCS/tech_pub/1984-stds-specs-geodetic-control-networks.pdf
An old document with a gentle introduction to designing networks with GPS see: https://geodesy.noaa.gov/PUBS_LIB/GeomGeod.pdf
Hope this contributes.
BTW, I like Dr Ghilani’s text on adjustment computations. A lot of pirated copies seem to be available for download. I contacted him about this.
He wrote a series of very useful articles including those on adjustments for Professional Surveyor magazine which may be online somewhere.
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To me, he seems interested in network design rather than adjustments in general.
Would you think that the principles that apply to a continental scale geodetic network also apply to a common development site survey?
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Dr. Shanlong Kuang’s text is out-of-print but may be available from resellers.
I will offer this book(1996 copyright) for the Fundraiser.
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@norman-oklahoma I have personally been experimenting with some of this on jobs usRTK base and rover and some terrestrial equipment. I have followed some of the “Wagon Wheel” approach es tha the NGS used or pushed in design for static networks. I have even used this on jobs where small baselines like one i have now is a 1 acre lot. We still run traverse around and done some cross ties with robots and i have independently enabled and disabled the different types of data to test results. Of course when i use all data more redundancy it shows how important that is. But to answer your question in my opinion redundancy and shape are key. Along with keeping that strength of figure in mind for adjustments. Now my crews doing this didn’t have to to observe control points for all the corners and control but they were in recon stage and it just worked out that away on one. So after playing with tge results i said why not i can always disable a vector tgat is not needed.
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@norman-oklahoma
from the original post: “…field work procedure that is needed for network adjustment measurements.”
As he does not specify what he plans to do, what standards he must satisfy nor other details my reply was intended to respond to issues of network design and specifications.
Having encountered folks who think they can perform geodetic work like they do their standard positioning projects, I hope to highlight the many differences and concerns.
One of Dr Shannon Kuang’s points is that you can waste time and money over-observing as well as not meeting standards by under-observing.
Does this answer your question?
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@geeoddmike that’s the thing that concerns me, i don’t want to be doing some adjustment performance that in my personal judgment is ok, but in fact does not follow a standard procedure or technical reference.
Maybe me question was “too general”, but the main point, having in mind to achieve the max accuracy despite the instrument that is to be used is this: what is the step by step procedure from going to the site to collecting the data.
-how we plan set up the instrument to take the shots if we have strong points from one benchmark to another, etc ?
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@norman-oklahoma large scale networks may take in consideration many parameters and factors for the adjustment, my question is simply for site development, step by step procedure for instrument set up and organization of shots.
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@danielj You could also look at the old ngs guidelines and standards specifications this was mainly for terrestrial observations but to achieve a certain order or class for field procedures example 1 second angle accuracy to achieve a 3rd survey you needed to turn so many direct and reverse angles. If a half second then less angles. This also provides you with intermediate direct reverses numbers that need to be met. Then DR. Gh. Has a article that i read years ago. And you can find that information and say you have a 5” angle gun. You can figure out how many angles direct and reverse to achieve a mean angle accuracy that is needed for a project. For rtk. There is william be nings classical rtk guidelines base and rover . Now some of this is out dated as our gnss is much better now. But still you can use those principles and solve for what is needed. For you to achieve. I use not to the tee but all those old examples and apply that to my field procedures. For my crews. Now i am not doing geodetic work but each project i know what is the minimum standard i need to achieve. I reverse engineer to get to that. I would say for typical if equipment is in good working order 4 direct and reverse angles should get you to where you need without worries for everyday work with no issues. If you have a bust something else is wrong. Someone didn’t plumb over point correctly or equipment is not in adjustment. Also field procedures change or can change if doing least squares for a traverse. You if your software can handle it now perform cross ties and multiple observation to a point from others and you do not necessarily have to run a loop like you need for compass rule. Thats a call for the PLS. When you are getting down to brass tacks. You need to understand your equipment specifications based on din or iso. Because that starts that 5” angle accuracy one total station thats 5” might be 5” after 2 direct and reverse readings. Another 5” total station might be 1 direct and reverse for example. Then the edm specs. Tribrach specs for centering. Rtk rod etc etc. having that understanding and the requirements you are trying to achieve will dictate what all field procedures are needed. I hope this helps.
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Amongst other things continental scale geodetic networks would be accomplished exclusively with GNSS, whereas the total station is far more likely to be used, at least in part, for site control.
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