WGS84 or NAD83?

[danieljohnbarnett (Daniel Barnett)]

I am testing my reach unit for accuracy with survey/benchmark marker.
I am testing it using PPK and RINEX data from a local CORS station.

The CORS stations lists their “known location” in NAD83 format. (I just select RTKpost to obtain location from RINEX header)
The coordinates for the survey marker are in NAD83 format.

I have read the reach units do WGS84. My question is… if the CORS station known location is in NAD83 would the resulting coordinates once processed be in NAD83 and match up to the survey marker (since they are listed as NAD83 also).

Or is there some WGS84 conversion that will take place in the reach units and throw it off?

[TB_RTK]

@danieljohnbarnett

My question is… if the CORS station known location is in NAD83 would the resulting coordinates once processed be in NAD83 and match up to the survey marker.
Or is there some WGS84 conversion that will take place in the reach units and throw it off?

No, but it would probably be very close.

[danieljohnbarnett (Daniel Barnett)]

Would it be more accurate to convert the “known location” of the CORS to WGS84 and enter that into RTKpost manually? If I leave it to pull from RINEX header it’s pulling the NAD83.

And then convert whats listed for the survey marker coordinates to WGS84?

Is the reach unit doing WGS84 in the raw files also?

[TB_RTK]

@danieljohnbarnett

Would it be more accurate to convert the “known location” of the CORS to WGS84 and enter that into RTKpost manually?

I would think so yes.

@danieljohnbarnett

And then convert whats listed for the survey marker coordinates to WGS84?

Yes

@danieljohnbarnett

Is the reach unit doing WGS84 in the raw files also?

From what i understand, yes.
Edit: or in X, Y, Z ECEF coordinates

[danieljohnbarnett (Daniel Barnett)]

When converting from NAD83 to WSG84 there is several version of WSG84. Which one is best?
ITRF2000, ITRF2008, etc…

Also It asks for the input date and output date.
Input date - Try to find when they surveyed the marker/CORS site?
Output date - today?

[TB_RTK]

@danieljohnbarnett

When converting from NAD83 to WSG84 there is several version of WSG84. Which one is best?

ITRF2000, ITRF2008, etc…

I assume the one used in the refrence system. Should be well documented in their spec.

@danieljohnbarnett

Input date - Try to find when they surveyed the marker/CORS site?

Output date - today?

This one too. Should be well described either on their service page or inside det refrence file. Or as a Read me

I usually dont work with nad83. I am located on the other side of the planet

[danieljohnbarnett (Daniel Barnett)]

The reference file just says nad83 2011 epoch 2010.

The website I am using to convert from nad83 to wsg84 has like 10 versions of wgs84 to pick from.
It looks like maybe the WSG84 has different versions based on the GPS week? G1150 for example.

Just wondering which one I should pick?

[garner5]

I find that I have a difficult time obtaining FIX without transforming my NGS NAD83(2011) station to WGS84 lat long ellip.

I use WGS84(G1150) exclusively.

Then I transform all collected points back to NAD83(2011) and use GEOID12B to get ortho heights.

[garner5]

https://www.ngs.noaa.gov/PUBS_LIB/gislis96.html

https://www.ngs.noaa.gov/NGSDataExplorer/

https://www.ngs.noaa.gov/cgi-bin/GEOID_STUFF/geoid12B_prompt1.prl

https://www.ngs.noaa.gov/cgi-bin/HTDP/htdp.prl?f1=4&f2=1

https://www.ngs.noaa.gov/TOOLS/Htdp/Htdp_transform.html

If you do not want to transform back to NAD83 and want to obtain Ortho H from the WGS84 use these for your geoid H:

NGA Geomatics - WGS 84?
Online geoid calculator

[danieljohnbarnett (Daniel Barnett)]

Right now I am just playing with obtaining a “known position” using one reach unit and PPK.
I am using a north american survey marker for the rover location to test how accurately I can do this.

I am using RINEX files from a local CORS station. The CORS station known location is in NAD83 (2011) with epoch 2010.

The survey marker listed coordinates are in NAD83(2011) with epoch 2010.

garner5: So if I am trying to test how well I can obtain a known position. I place my rover right over the “survey marker” which is listed online using NAD83. The height seems to be listed as NAD83 also right?

Then I would do PPK using the CORS staition and my rover raw files. I would convert the CORS station known location to WGS84 (1150). and run the plot. But then convert that back to NAD83 to verify accuracy?

[timd1971]

Have you had any success here? I am curious also about using NAD83, State planes, Geoids, ortho heights vs. Or coming from WGS84 and Ellipsoid conversions.

Trying to get a good workflow here using all of this properly.

I am using MicroSurvey FieldGenius which requires setting a coordinate system to work in. i.e. NAD83 or a State Plane. I am looking at some apps that can use UTMs also…such as MapIt and Mobile Topographer. MapIt looks promising with the extensions of course.