What datum is is the Global CS ellipsoid height?

I have been attempting to determine what the vertical datum is when using Emlid’s Global CS. I am collecting GPS points using Reach view3, with the reach rs2 base and rover.

Hi @kylepaulekas,

Welcome to the community forum!

With the Global CS option, you get geographic coordinates and ellipsoidal heights related to the same datum as your base. So if you set your Reach RS2 base in NAD83, you get NAD83 coordinates and heights on your rover.


What if I am not specifying specifc coodinates for the base, but using an a 2 minte average over a single unknown position. I am using the Base and Rover for drone gound control in remote locations. When I set up the base I use the average single with a 2 minute accumulation time. Then when I set up the rover I am using the Global CS option for the project.

Then you are in WGS84.
Single mode puts you in WGS84 datum. So the ellipsoid height in that case is the height above the WGS84 ellipsoid. Funny thing is WGS84 name is used both for the datum and the related ellipsoid.


Here’s a great resource for info

There are several different flavors of WGS84…


Hi @kylepaulekas,

Yeah, I can second Florian’s thought: Average Single provides you with WGS84 coordinates. So if you use them as a base position in RTK, Global CS option on the rover will mean WGS84 as well.

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