OPUS Check to GNSS Solutions

Jimmy call me when you get a chance..

City Survey 901 729-2822

Clarification!!!

The City of Memphis Benchmarks check good with the OPUS results. The problem IO am having is with something I am not doing right in GNSS solutions.

WAG

"""I process all six points in GNSS solutions, and set the two city benchmarks as vertical control, and I am missing the OPUS elevations by about 6 feet.
"""

WAG; if you are missing opus by about 6', resubmit and double check your ARP ht. a two meter pole is approx 6.562'

6' is roughly 2 meters. i would guess you didn't set your rod height right in GNSS.

Thanks Guys,

That hit me a few minutes ago. Something is off by about two meters, but everything looks like it is right as far as rod heights. It is something simple, as it usually is. I'll let you know what I find out.

Thanks,
Jimmy

I am totally stumped. I have no idea what is wrong. I sent an email to Hayes, and we'll see what they have to say.

Thanks for the suggestions.

I have double checked everything, and cannot get this figured out. I have a topo that I'm working on , and need to get out the door by the end of the week.

Any suggestions would be greatly appreciated.

The rod heights are correct in GNSS Solutions, as well as Topcon Tools. The only thing that I can figure is that possibly something went awry in the rinex conversion from Tools.

We will see.

Thanks,

I don't think that the GNSS is the problem. We have problems with the data from time to time, and there are some things to check:
1) if you can upload the date sheets OPUS spits out on here so we can look at them.
2) make sure that all of the settings on your OPUS page is correct, many times the wrong antennae is chosen which causes all kinds of problems.

Do you use any editing software to filter your GPS observations?

Clarification

I meant do you use any software to edit the rinex file before submitting to opus? also, I should probably read the steps a little closer, but if opus and topcon tools checked then why would you use GNSS? as a third check on two already really good methods? Maybe I misunderstand what you are trying to do.

Clarification

C.Thompkins,

Thanks for the reply.

I currently use GNSS Solutions because I can process more than 5 points in the project. I only have the Topcon Tools Demo version, which is limited to 5 points per project. Most of my baselines are short enough that the L1 only solutions are more than adequate.

I use the OPUS as a check to make sure no blunders occur. I generally don't edit my data before submitting to OPUS, as I generally get pretty good results. This is the first time that I have ever really had any problems.

After speaking with Randy at Hayes, it seems like one of my rinex files was corrupted when I exported it from Topcon Tools. Of course, it was the main point that I was using as my check with the L1/L2, and transferring in the elevation from the two City Benchmarks.

After a fresh download from the receiver, and also using the most up to date download utilities, I was able to create a new project, and processed acceptable results. I also updated GNSS Solutions, Topcon Tools, made sure I had the latest Geoids, and also updated all the appropriate download utilities for both Topcon and Ashtech.

I generally try to run the processing through both Topcon Tools and GNSS Solutions, just to try to make sure I am getting good data.

Thanks,

Clarification

Thanks for the update. I tell ya'. GPS is great for a lot of applications, but when something as stupid as a 'corrupted rinex' file occur, it will literally drive a surveyor crazy, occupy his mind, and quite possibly cause a panic attack like the one which you just experienced.