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I have done several opus solutions for points and then checked into published benchmarks in the area and are missing the published elevation by +0.5' to +0.8' consistently.  I did an opus solution on a first order, class I benchmark and still was +0.5' above published info.  It seems like a systematic error and I am not sure how to isolate or find the error.

Hi Guy,

Can you give some more detail about the workflow you are using?  What Trimble software are you using so that we can better address the question?

Thanks,

Adam

HI Adam,

I am using Trimble access (not sure how to find the build version, but it was upgraded last year) on a TSC3 data collector.  R8 Model 3 Base and Rover.  Submitted file in TBC version 5.2.

Is this what you are looking for?

Guy Bien

Eastern Sierra Land Surveys, Inc.

(760) 935-4920

What is the information for this benchmark? When was it adjusted?

How long are you static observations?  Are the heights entered into OPUS correctly to the right part of the antenna?  The most common source of error in surveying is measuring device height errors.

I don't see anything in your attached image.@Jeff Jalbrzikowski

My static observations range from 1 1/2 to 2 1/2 hours.  I have double check and the height is measured to the correct part of the antenna.   I did not attach any image.  I have emailed several files to Ben Messner from the TBC QC Group for examination.  I am not sure if I attached files to this message board.  I can email them directly to you if you wanted to take a look.

What about the information on the existing benchmark you are checking into? That could possibly be in error.  I had a similar situation that @Jeff Jalbrzikowski noticed odd information in the data sheet that might have indicated the elevation published wasn't correct. That's the conundrum with static points, is that data published correct.

I checked into 3 BM's near the site and did one OPUS solution on another and was still 0.55'-0.78' high.  So I believe the published data was correct.  I did OPUS solutions on two other BM's about 45 miles and 180 mIles away and they were close at roughly 0.10'. 

Hi Guy, I'd be happy to take a closer at this if you can share the PIDs of the BMs you're checking in to. And share any static observation files you're willing. 

If you'd prefer, you can find my NOAA NGS email on our advisors homepage here: National Geodetic Survey - Regional Geodetic Advisors

I would initially suspect a bad HI, but if you've already chased that angle there's a few other possibilities.