North Carolina RTN

[Greg Flowe]

Has anyone working on the North Carolina RTN noticed any errors in the vertical? I have heard from my Leica Dealer today that has a couple of large firms using their equipment having noticed 0.2' of constant error when checking into NCGS Monuments and control over the past week. Their systems are using both GPS & Glonass. I told them that I had been only using my T1M & LS as a base & rover, but I would ask around. Thanks

 

[Adam]

I have seen errors of that order vertically on the network since I started using it in 2011

 

[Adam]

Sometimes it's ok but I wouldn't ever bet the farm on a vertical network solution. I have heard from some Javad users that have had good results most of the time with at least 8 min observations. That may be true. I really like my base and have staked sewer, water, drainage, building pads, and curb using my base and the LS. All the water and shit goes downhill and the curb stringlines look good. They were prepping for pouring the curb last time I was out there. I wouldn't do all of that with the network.

 

[Greg Flowe]

You have that right. I would not stake anything of consequence with the RTN if I have the base option. Adam Thanks

 

[James Suttles]

I ran some RTN on Thursday of last week, and ran thought the same points today, and there was about that much difference. It was very consistant also. The verticals I got today were more in line with what I got with the level before.

 

[Wes Cole]

I have also been seeing unusual differences in RTN elevation on the network over the past couple of weeks. A project last week had observations on 3 points two different days and elevations differed by around 0.25'. This has been consistent with the LS and another manufactures unit as well. I have occasionally encountered those variances on the network over the years but not consistently.

 

[Greg Flowe]

Thanks for taking the time to post the info, I will pass it along. I believe they are talking to Gary Thompson at NCGS to see if they are seeing the same thing. I will post anything I hear on my end. Thanks again

 

[James Suttles]

Just got off the phone with Bart @ Geodetic. They are not sure what is happening,but Geodetic is checking it now. They are getting calls from mostly Spectra Precision customers, but when I told them I was using the the Javad, equipment and that I had some Topcon Hiper equipment, he, Bart, realized its not a specific manufacture issue. He said they had turned on L5 and thought maybe that was the issue, so they turned it off, and the problem still existed. So its back on now. They have a crew in Mooresville checking, the Asheville office is checking some points in Waynesville, The Raleigh office is preparing to start checking and the Asheville crew will be checking some in Burke County tomorrow, so they are on it.

It looks like the vertical is giving out about 0.20 vertical error, across the State. They are not sure as to why, as they have not made any statewide changes in the system. Concord Engineering reported it first, Transit and Level has reported it, and I have reported it, so its definitely an issue.

Will update once I know more.