I little question about the reach rs+ giving height

I am testing with a reach rs + receiver as a rover.
All observations are taken when I am connected to a reference station using NTRIP in RTK mode , the longitude and latitude coordinates are ok but the ellipsoidal height give me reach rs+ is wrong,
I have been collecting data from several knowning geodesic points and they all give me an error in the heigth (only heigth because longitude and latitude is correct)
I’ve seen the forum but I have not found any answer to my problem. I would be grateful if is someone could give me the appropriate indications for the reach rs + me give the correct ellipsoidal height.

The known points might not be ellipsoid height, but some local reference?
Can you post a link to your known points documentation?


As @wizprod stated, also keep in mind that the RS+ using ReachView is providing the ellipsoid height no matter what anyways. You can use third party software (or website converters etc) such as FieldGenius, Carlson SurvCE/PC to give you real time heights for how you need. i.e. GEOID etc. There are some android apps also, Mobile Topographer, MapIt PRO GIS etc.

I will 3rd the elevation types. Ellipsoid, Geoid and Ground - and there are multiple versions of each.

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I have not used the Reach, i only have an RS2 on order…

It sounds like the GNSS height is just the raw height above ellipsoid (HAE). You will need a geoid model to generate the more conventional orthometric height above mean sea level.

If ReachView does not yet support geoid models and calculation of orthometric height on the fly you will have to use an external utility or other field software to determine the MSL heights… As mentioned…

I use the transformation utility offered by the Canadian Geomatics division. It allows you to select which vertical datum and geoid model you want. Not sure if it applicable globally.

Canada GPS-H Utility: https://www.nrcan.gc.ca/earth-sciences/geomatics/geodetic-reference-systems/tools-applications/10925#gpsh

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Someone has to have thought about this process. Interesting how there are total control conditions that can be done with a drone and not terrestrial surveying when it comes to GPS. Land surveyors use robots and levels. Terrestrial surveyors work globally. I can fly a drone with a base, ppk, tag some GCP’s! and my survey is absolutely relative to the project. I am not that versed in PPK yet, but it sure sounds like something that could be configured for? I’m sure a brainiac will chime in. This could solve about 20% of the posts in this forum, lol…

While I agree it’s a possibility, it would also take much more time to do, given that you have to run the survey, then post-process GCP’s, then post-process aerial imagery.

Btw, what is the difference between a terrestrial surveyor and a land surveyor ?

Aren’t they the same? Ground based surveying on or near the surface of the earth?

Droning was just an example so it was more about doing the survey and capturing a few locally collected “GCPs”. Then project past the native transformation to state plane to use the GCPs to account for any shift or scale factors. Effectively localizing after the fact.

Land Surveyors - Local ground
Terrestrial - GIS

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