Web Dpos vs NCRTN

J

James Suttles

Active Member
I have ran 2 separate projects, and I get an elevation difference of 0.375 to 0.435 difference between the NCRTN location and the Web Dpos derived location. I expect some difference between the two setups, but its never this much. I would expect a 0.10' or so, but when it us close to the APC that we had to add in our old LS to LS setup, it raises the question, could something be missing from the setup. We run an LS as a base and a LS Plus as our rover.

The procedure is to collect 3, 240 second (2) Multiconstellation verified boundary shots, using the NCRTN. We then cluster average those 3 collected points, and set the average point as our base coordinate. We then locate the all parts of the project, (ie corners, road location, etc. ). After we are back at the office we download the base file and upload it to WebDpos just to check the 3 shot average.

We are seeing the difference of 0.375 to 0.435 difference consistently on the WebDpos vs the NCRTN. The NCRTN is always higher than the WebDpos elevation. It looks like the APC is not being accounted for either in the HI of the LS when its taking the NCRTN location, or when its being reduced with WebDpos.

We even compared the results with OPUS and those results are matching the NCRTN, elevation, within less than a 0.10'.

I would upload the files but they are over 100mb each. If you need the files I can setup a Dropbox in order to download them.

@Alexey Razumovsky
 
Adam

Adam

Well-Known Member
5PLS
I suspect this is something that is particular to your LS base or web DPOS. I use the NCRTN to set my base points as well. The last 2 DPOS projects I've done have agreed within a couple hundreths of my starting NCRTN point. How did the DPOS from J-Field compare? When creating the base point and DPOS session are you doing it manually with the 3 step process or from file? I do it manually out of habit. I'm spit balling to see what is different between us. I'm sure you are up to date.
 
J

James Suttles

Active Member
I did not use the LS to DPOS the file. I downloaded the file, submitted it to WebDpos and the results differed. I just submitted the files via DropBox to Alexey.

Curious if you submit your info to WebDpos if you get back a confirmed elevation.
 
Adam

Adam

Well-Known Member
5PLS
James Suttles said:
I did not use the LS to DPOS the file. I downloaded the file, submitted it to WebDpos and the results differed. I just submitted the files via DropBox to Alexey.

Curious if you submit your info to WebDpos if you get back a confirmed elevation.
Click to expand...
I'll send one in a little bit.
 
Adam

Adam

Well-Known Member
5PLS
It matched to the elevation of the rtn and J-Field dpos within a few hundreths. When you run Web Dpos are you selecting Vertical/Slant as needed and entering in the height?
 
J

James Suttles

Active Member
I uploaded the file and submit for processing, I am not picking slant of Vertical. We measure to the bottom of the unit, no adapter. I have never had to select either of those options in the past to get the proper elevation. I have gotten the files to Alexey. Curious to see if he gets a difference.
 
J

James Suttles

Active Member
The coordinates from the NCRTN on the 1st base file are as follows:

21721Base is:
NCRTN = 618417.500 1960062.690 432.175 Base
WebDpos = 618417.474 1960062.566 431.813 Base

The NCRTN point was verified by using another surveyor on site, using a Spectra Precision GNSS receiver. They submitted their static file to OPUS and it confirmed the NCRTN elevation.

I will have to get the other NCRTN base point when the crew returns this evening.
 
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J

James Suttles

Active Member
Also in speaking about the being too Noisy part, I have been having that quiet frequently. We just thought it was something at a certain job site. Apparently its more that just that site.
 
Adam

Adam

Well-Known Member
5PLS
James Suttles said:
Also in speaking about the being too Noisy part, I have been having that quiet frequently. We just thought it was something at a certain job site. Apparently its more that just that site.
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Doug, do you have reset tracking set to 0 in the base profile, advanced, rtk settings? It is on 120 by default but should be set to 0 for LS base setup. I'm not sure that's the problem, just curious.
 
J

James Suttles

Active Member
@Alexey Razumovsky I am still having an issue, getting a file from DPOS. I sent it this AM and it uploads, but never processes. I converted the file to a RINEX to submit to OPUS, and OPUS gives and error of no ephemeris, try back in a day or two.

I have uploaded the file, to the same drop box link, check you messages for the link, to see if you can tell what maybe causing the issue.

Thanks
 
D

Dmitry Ostrikov

Active Member
JAVAD GNSS
Steve,

Main DPOS server processing engine was out of service. Now the issue is resolved. Please check your data had processed or re-submit it one more time.
 
Alexey Razumovsky

Alexey Razumovsky

Well-Known Member
JAVAD GNSS
5PLS
James Suttles said:
@Alexey Razumovsky I am still having an issue, getting a file from DPOS. I sent it this AM and it uploads, but never processes. I converted the file to a RINEX to submit to OPUS, and OPUS gives and error of no ephemeris, try back in a day or two.

I have uploaded the file, to the same drop box link, check you messages for the link, to see if you can tell what maybe causing the issue.

Thanks
Click to expand...
I expect the issue was resolved
 
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