So I have a VRS subscription to a statewide VRS network but it is in NAD83(2011). My LiDAR and Camera setup needs to be in WGS84. So I elected to set up my RS2 and via the VRS get a known point and leave it connected for a FIX. Then I did the corrections output to the emlid caster. My drone’s RTK has a cellular modem and thus connects to the emlid caster and RS2 for its FIX. My question is, by leaving the RS2 connected to the VRS subscription and continuing to refine its point, does that in turn relay to the emlid caster, or does it only rely on the base mode and 2-minute observation that I did to get the known point? I’m trying to determine if over time, the VRS FIX the RS2 is getting will improve any rovers that are connected through the emlid caster.

As I understels your setup, your known point will be in nad

If you have VRS access do a good 30-second RTK shot to generate that base point and you are about as accurate as you are going to be without much more extensive processing. While you had a NAD83(2011) point it still has a WGS84 lat/lon associated with it and that is what the rover(drone) will use.

That begs the question though why not just use the VRS for the drone?


My understanding is that reachview provides both NAD and WGS. Given that in the base mode, it collects as WGS, that is what I need.

Going directly through the VRS from the drone pushes me to NAD. For all parts to match, I need WGS.

The RS2 does nothing to transform. It doesn’t know what it is receiving.
What it gets is what it transmits. So, feed it nad, and you resulting coordinates will be in nad.

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Oh. So your service doesn’t provide different mount points?

When I look at the CSV that I export, it shows the state plane and the WGS84… Is that done within ReachView? Also when I look at the point in base mode, it shows as a WGS84 point when I average for a 2 minute observation to set the manual base point.

Ive got an email into them asking.

Ohio has 6 or 7 mount points but they are all NAD83.

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I’m confused on how RV2 pulls WGS84 for base mode when connected to an ntrip is in NAD83. It has to be converting it in the app.

Where do you see WGS83? The base coordinates in decimal are the same as you input in the base mode.
ReachView 2 or the RS2 itself does not support transformation on its own.
As mentioned before, the base simply doesn’t know what input system you feeding it, and there is no way currently to defining for the base.
And within knowing your input, you can’t transform your output either.
So, whatever your VRS is in, your resulting positions will also be in, even with RV3.

Great, now I’m confused. I checked our RTKNET and both of the mountpoints they gave us are technically NAD83 but we have been using them to correct our RS2’s and our drones. I haven’t seen any discrepancies so what am I supposed to be seeing?

You guys are dealing with post processing. This creates more of an issue. Glad I have the “simple side” of GPS :wink:

Discrepancy between the drone and the RS2 or how do you mean?

I would say post-processing is much less of a black box, as you have all components under your control :smiley: With RTK VRS there is so much black box going on that it is easy to be confused, if the NTRIP provider has not been pretty explicit about what is being transmitted.

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Did you leave them as the coordinates out of The RS2 or did you convert them?

The GCP’s via the RS2, the drone map as exported to our local State Plane into CAD and the Drone map as exported to WGS84 brought into a WGS84 QGIS project. I am new to the whole CORS via NTRIP thing so if I don’t see any discrepancies when pulling my data into different sources then I don’t know that something is wrong. I have seen that the difference between WGS84 and NAD83 can be a meter but I thought that was a direct coordinate transformation and separate from the math of the corrections?

If you imported correctly into QGIS, then the transformation should happen there.

Maybe explain your 2 sources of input? As I understand it, you have GCP’s, and you have drone images with geotags?
But haven’t you used the same base correction for both?

Ok so QGIS could automatically be transforming from NAD83 to WGS84… I think the drone data fits because my GCP’s are shot and uploaded to processing in a NAD83(2011) SPCS so whether you are transforming from NAD83 or WGS84 out of processing to State Plane it ends up at the same place. Or processing with GCP’s just fixes that meter or whatever it was. :face_with_raised_eyebrow: