Transforming ITRF14 lat/lon/height obtained from NRCAN CSRS-PPP service to WGS-84 lat/lon/height

Hello,

Was anybody successful in transforming the ITRF14 lat/lon/height obtained from NRCAN CSRS-PPP service to WGS-84 lat/lon/height? (If I understood well, the coordinates for the base have to be in WGS-84.)

If yes, would you explain to me how you achieved this, with an example if possible?

Thanks in advance!

I cant get to it right now, must be a network issue
but use HTDP from NGS

https://www.google.com/search?q=ngs+htdp

and the coordinates for the base just have to be in latitude longitude.

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Do either of you happen to know which version of the ITRF NRCAN uses? If I can find that out, then yes you can post process with NRCAN and convert to WGS84 using htdp. From there you can convert again to state plane using NCAT (https://geodesy.noaa.gov/NCAT/). That would be a great way to finally establish a solid workflow for a point that you cant get a tie to or localize from a nearby benchmark (rural areas).

The processed files will state which ITFR version it is. Current is 2014 and Epoch will be the time of your recorded observation

try this one on http://www.epncb.oma.be/_productsservices/coord_trans/

I have used this on with NRCAN results before. Worked just fine :slight_smile:

Thanks for the replies. Before I post this question, I had tried to do the conversion using the epncb.oma.be URL. However, it requires Cartesian ITRF coordinates to work, not lat/lon ITRF:

–> Example with velocity - StationName(no space character) X[m] Y[m] Z[m] VX[m/yr] VY[m/yr] VZ[m/yr] :

StationName 4027894.006 307045.600 4919474.910 0.01 0.2 0.03

It appears it is possible to do that transformation using this URL: https://geodesy.noaa.gov/cgi-bin/HTDP/htdp.prl?f1=4&f2=1

However, there are several equivalence between ITRF and WGS-84, depending on which version of WGS-84 we want to do the transformation to:

WGS_84 original
WGS_84 G730 <–> ITRF91
WGS_84 G873 <–> ITRF94
WGS_84 G1150 <–>ITRF2000
WGS_84 G1674 <–>ITRF2008

What WGS_84 does Reach require?

Thank you Tracy!
Do you know which WGS_84 Reach require, by any chance?

Only WGS84

So, WGS_84 original?

if you log data on a point and then send your log file to NRCAN to be processed you will get a X,Y and Z value back. you will get a latitude and longitude back with a height above the ellipsoid all in in ITRF2014. you can then set you base station to those coordinates and all of your resulting rover work will be in WGS84 ITRF2014. if you want your base station coordinate to be in nad83(2011) then use something like HTDP to give you the nad83(2011) equivalent of your WGS84 ITRF2014 value. then if you use your nad83(2011) x,y,and Z values as the location for your base station, all of your resulting rover work will be in nad83(2011).

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If I understand your explanations correctly, you are suggesting me to use ITRF2014 and WGS_84 interchangeably for my base (which is what I have done last week because the targets I used as ground control points are at risk to disappear and I had to secure a measurement of their position in case it happens.

Although from my readings I understand there is not much difference between the most recent ITRF solutions and WGS_84, it remains that there can be up to a few centimetres differences, which, when those positions are used to correct and georeference UAV images, can be a problem, especially if ground sampling distance of the said imagery is less than 3 cm. Ideally, this error should be minimized so that it does increase the total error generated by the orthorectification, error which should not exceed 1 to 1.5 x GSD as per remote sensing and photogrammetric standards.

well almost, depends on your target concept of accuracy i guess

my understanding is that the current WGS84 reference frame is dictated by the ground control segment of the GPS system and that it is currently based on IGS08. if you see something contradicting this then post away.

From what i have read the difference between itrf2014/igs14 and 08 is subcentimeter. once again if you have a online source saying otherwise please post, cause i need to know.

as a side note, I havnt used NRCAN for quite awhile so i decided today to run some data through it. i have a CHC-igage receiver that is built for OPUS work. i ran the rinex from a four hour observation (northern California USA ) through NRCAN and the results were 0.0157 m off (ngs inverse) from the results from OPUS which i reran to double check. i am actually surprised its that close. i think they are using the same ITRF products in their process but that right there makes me want to know more about a pure PPP based rover system. sorry thats kinda a thread drift there.