Tip of the Week #29 - Sources of Default Standard Errors

By Joseph Blecha posted 02-23-2018 12:54

  

Network adjustments are all about detecting, managing, and distributing errors throughout your data.  Beginning the adjustment with accurate initial estimates of your total station, leveling, and GNSS errors assists the least-squares routine in the network adjustment workflow.  Where does TBC get these initial estimates?  Read on…

In the TBC Project Settings, there is a Default Standard Errors header that, not surprisingly, contains the settings that the Network Adjustment routine uses for the initial error estimates.

The default for total station data is set from the imported file, like a *.job or *.jxl.  These settings are likely set in the field software like Trimble Access and the accuracy of the instrument should be considered to establish a proper estimate.

The default for level data is set by the Level Editor, launched when you import a *.dat from a Trimble DiNi, for example:

The default for GNSS data is the result of processing the baselines.  These results are reported at the conclusion of the processing in the Baseline Processing Report:

These default settings can be changed by selecting a different source from the drop-down menu:

The Project Settings options can be set in the corresponding sub-header.  For example, if you set the Total Station source for standard errors to Project Settings, click on the Total Station sub-header to manually set the errors to use in the adjustment.

Now, armed with the knowledge of where the Network Adjustment routine takes it initial error estimates, adjust your network confidently!

 

Trimble Business Center - Field to Finish with Confidence

22 comments
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Comments

03-07-2019 15:43

Indeed these values should be filled automatically from the total station measurements and BS closure to be used in the network adjustment during the surveys

03-06-2019 08:03

Quite a few versions ago, I tested that and as I recall it was all zeroes.  Yikes!  But I always set the defaults in Access for actual work.

03-04-2019 09:39

Hi Alex, I am sending you an email to see if we can fix this for you.

03-01-2019 12:35

I wonder what Total Station precision/default standard error value is imported from a job file if you don't set it manually by ticking the Instrument Precision tick box in an Access Survey Style. 

03-01-2019 11:34

Confirmed. I am using TBC Advanced V5.0 and I do see the default standard errors for total stations. I use them on every network adjustment. 

03-01-2019 11:08

Hey Roger, regarding that, we also have a network licence that is Advanced, and we are still unable to change the default errors for a total station.

 

Just to confirm 100%, is everyone else running TBCv5, and are able to change the default standard errors for a total station?

 

Thanks,

Alex Cook

03-01-2019 05:39

There is your answer. Need to be on Survey Intermediate to have Network Adjustment.

02-27-2019 18:09

TBC Base

 

Thanks,

 

Alex Cook    I    Surveyor

 

 

 

 

P: 07 4637 9790   M: 0437 384 860 E: alexc@minstaffsurvey.com<mailto:alexc@minstaffsurvey.com>

319 Margaret Street, Toowoomba  I   PO Box 974, Toowoomba QLD 4350

www.minstaffsurvey.com<http://www.minstaffsurvey.com/>

 

 

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02-27-2019 18:07

And by version I meant Advanced, Basic etc.

02-27-2019 18:06

Interesting. Do you mind if I ask which version of TBC you are running?

02-27-2019 18:02

Hey Mark,

 

Yes I did, the GNSS and Levelling DFE options returned after the restart, but there is still no option for Total Station

 

Thanks,

 

Alex Cook    I    Surveyor

 

 

 

 

P: 07 4637 9790   M: 0437 384 860 E: alexc@minstaffsurvey.com<mailto:alexc@minstaffsurvey.com>

319 Margaret Street, Toowoomba  I   PO Box 974, Toowoomba QLD 4350

www.minstaffsurvey.com<http://www.minstaffsurvey.com/>

 

 

This email (including all attachments) is the sole property of Minstaff Survey Pty Ltd and may be confidential. If you are not the intended recipient, you must not use or forward the information contained in it. This message may not be reproduced or otherwise republished without the written consent of the sender. If you have received this message in error, please delete the e-mail and notify the sender.

02-27-2019 17:54

Alex, 

Did you restart the program after getting the license issue worked out? The changes only take effect on restart.

Mark

02-27-2019 17:23

Hi Mark,

 

You were right, and my licence hardware wasn’t being recognised, but even with that fixed, the option to edit the standard default errors for Total Station data has been removed.

 

 

Thanks,

 

Alex Cook    I    Surveyor

 

 

 

 

P: 07 4637 9790   M: 0437 384 860 E: alexc@minstaffsurvey.com<mailto:alexc@minstaffsurvey.com>

319 Margaret Street, Toowoomba  I   PO Box 974, Toowoomba QLD 4350

www.minstaffsurvey.com<http://www.minstaffsurvey.com/>

 

 

This email (including all attachments) is the sole property of Minstaff Survey Pty Ltd and may be confidential. If you are not the intended recipient, you must not use or forward the information contained in it. This message may not be reproduced or otherwise republished without the written consent of the sender. If you have received this message in error, please delete the e-mail and notify the sender.

02-27-2019 16:26

Alex, 

You might want to verify your hardware lock is in or that it is set to network (or whatever your situation is). I have 5.0 and the options are in there just like the screen shot. The last time I noticed nothing was showing up in settings  I also noticed I forgot to put my hardware key in for the scanning module and when I updated to 5.0 the settings reverted to hardware from the network option.

02-27-2019 15:31

Hey matt,

 

That option and image is correct for TBC v4, but we recently updated to v5 (5.0.6893.26272 is what I am currently running) and those options have been removed (see below screenshot).

 

 

 

Thanks,

 

Alex Cook    I    Surveyor

 

 

 

 

P: 07 4637 9790   M: 0437 384 860 E: alexc@minstaffsurvey.com<mailto:alexc@minstaffsurvey.com>

319 Margaret Street, Toowoomba  I   PO Box 974, Toowoomba QLD 4350

www.minstaffsurvey.com<http://www.minstaffsurvey.com/>

 

 

This email (including all attachments) is the sole property of Minstaff Survey Pty Ltd and may be confidential. If you are not the intended recipient, you must not use or forward the information contained in it. This message may not be reproduced or otherwise republished without the written consent of the sender. If you have received this message in error, please delete the e-mail and notify the sender.

02-27-2019 14:54

Hi Alex,

 

Default Standard Errors can be changed in Project Settings, Default Standard Errors, Total Station and Levelling, and those entered errors can be selected to take priority over imported files from the root DSE menu as shown by the arrows on the right. Does that answer your question or is something else going on?

 

Cheers,

Matt

02-13-2019 23:02

Hi Team, we have just updated to TBC V5 and the ability to set the default standard errors for Total Station and Digital Level data seems to have been removed.

Is there a way to enable this again? Or another way to edit the default standards errors?

Cheers, Alex Cook

03-02-2018 03:41

It would help if TBC collects and includes in the reports, the total station/digital calibration calibration constants and environmental values used to compute the EDM's PPM factor applied to each shot taken and show it both in RAW data editor and network adjustment with Least Square/Montecarlo standarized methods by ISO in TBC.   

 

Also related as input and editing of total stations and GNSS measurements and their residuals prior and after instrument calibraton and Least Square Adjustment are defined by ISO https://www.iso.org/obp/ui/#iso:std:iso:17123:-5:ed-3:v1:en 

https://www.fig.net/resources/proceedings/fig_proceedings/korea/full-papers/pdf/ws_com5_3/zeiske.pdf 

03-01-2018 11:34

You will also want to include instrument and backsight centering error and height error or you may fail the chi squared on the high side because your a priori will be unrealistically optimistic.. A good centering error is 0.005' (CalTrans standard I believe) and depending on whether you always use a stationary backsight you may wish to increase it depending on the rod bubble you use. I agree that least squares is an awesome tool for finding blunders. Rod busts and prism constant errors jump right out at you and you can isolate the vectors where the error is coming from really easily so you know right where to look.

02-28-2018 14:26

Thanks for the feedback. This is something that's been requested before and we are aware of.

02-27-2018 07:47

I agree Alexander. Least squares isn't just for adjusting anymore, especially with how well these instuments and technology perform, but, there's nothing like least squares to find our own mistakes to correct them quickly. Also, outputting the positional tolerance along with the resulting coordinates is not possible without least squares. I wish TBC could add those columns to the points spreadsheet, ie, Ne, Ee, and Ze, and/or add the point descriptions to the adjustment report.

02-24-2018 05:23

Excellent and much needed information on these standard errors and its values... keep on adding more details to these in TBC