Elevation difference Question


Reach working well, i have 2 RS+ units ( Base and Rover ), I have not issue staking out points so far. x and y value we very happy with. Howerever I have a question:

A land surveyor got a elevation on a point as 1427.13m M.S.L on a bridge nearby us.
I went to a old suveroy beacon nearby, whose cordinates I have. I got <30cm accuracy on Zaxis on that existing value.Which is acceptable.
I then to the bridge which they did a point on and I get 1424.88m M.S.L To reduce any discrepancy, I placed both base and rover directly on the curb about 1m apart. so there was no difference in height between them. I got a fix solution. So what could the difference be then?


First off, you DO NOT want to just place them directly on the ground like that in your photo!

Put them both on survey rover poles with a set height i.e. 2m rover pole is convenient. And enter the total height of pole plus thread adapter plus height to antenna (printed on bottom of RS+).

There are many posts abouts rover poles, tripods, rover pole tripods, bipods etc.

Recent post:

Hi ,

Thanks, I did place on survey pole and tipod on previous try. I just placed on floor for a test, even sub meter accuracy do as test.

Here we go again with the ellipsoid vs geiod vs survey ground coordinates… 30cm is ok?

Hi @dmterblanche,

I agree with @chascoadmin.

In the meantime, you can see only the ellipsoid height in ReachView. You can get orthometric height after post-processing, using RTKLIB. Check our GPS post-processing guide for it.

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