Height above MSL or orthometric/geoide/ellipsoide discussion

Continuing the discussion from ReachView 2 beta Suggestions/features request:
To continue the topic here…

Reach outputs ellipsoide height, but not all apply local correction data, like me with href2016b.
They apply a global EGM96, GEOID12 etc. Also found in the RTKpost under options. Is anybody working in this format? and how accurat do you need the height to be? and does it just have to be relative to the base? (if base i adjusted to correct ortho height)

Which brings me to the next question, if base i set to known height (corrected any datum i guess) ,will rover output corrected height and also adjusted for the deviation that the rover is actually not in the same place as the base? ( orthomtric height above msl/geoid is not the same when you change location)
Sorry for bad formulation. Any input on how to use RTKlib in this area is welcome

1 Like

You have a good question, unfortunately i don’t know the answer yet, so i guess the best way is to continue using local correction in postprocess if you can.

In my case (Dominican Republic) we don’t have a local geoid, we use EGM2008, today was my first flight data postprocessing in RTK LIB, and as i have experience using other postprocessing software, i was looking for geoid option, i found it, but is very vague, i tried three different geoids files format and none of then worked.

I am getting ellipsoidal heights in the .pos file, it is because the base station is configured to output ellipsoidal heights, after your question, i am confused about how corrections from base with known “elevation” works, because the “zero” elevation reference is not the same in every location, which makes me think you would still need a local geoid file loaded on your rover software controller .(?)

Anyways, i need elevations above M.S.L. which is what we get after applying the geoid correction, i don’t care if EGM2008 it is not that much accurate, because in any case, comparison will be made using GNSS recievers with data collectors which also use EGM2008 corrected elevations, so we will be all playing the same game.

I will try to get more information about that in land surveying forums and let you know.