Emlid

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Base Mode Manual - Elipsoid high vs. Geoid high


#1

Hello,

i have a question about the manual mode for the Base Station.
I use 2 Reach RS+, one as Base and one as Rover.

I mainly work in Austria and Germany.
For the Base i know the coordinates in my local coordinate system (like Gaus-Krüger) and the high (geoid high above Adria or above normal null).
For the manual mode i have to transform my Gaus-Krüger coordinates into WGS84. This is pretty straight forward and simple. And I assume it is also accurat enough (i transform the coordinates with QGIS).

But the high transformation is not that simple, i did not manage to do it rigth.

So my question is: If i imput the base coordiantes in WGS but did not transfom the high an imput the high of my local coordinate system will i get correct high data from the rover (relative do the Base high)? The distance to the rover will be not more then 5 to 10 km.

Thank you for your help.
Benni


(Michael Lambert) #3

Last time I did this it reported my base height correctly from the GEOID value I input, but the rest of the shots I took were relative to that point per the ellipsoid model. You might try this site. It was close for me, but we use local benchmarks so it still wasn’t what we needed.

https://www.unavco.org/software/geodetic-utilities/geoid-height-calculator/geoid-height-calculator.html


(Andrew Yushkevich) #4

Hi @geoscience.WiB,

What problem did you face while transforming height?

It’s better to have all coordinates in WGS84 to have an accurate result.

Overall, did @chascoadmin link help you?


#6

Hello Michael, Hello Lambert,

thank you for your response.
I am just not sure about the right hight transformation. IN Austria and Germany there are many different reference altitudes (older ones and newer). So it is not always clear wich reference altidude is the correct. So i wanted reduce the transformation steps.

For my current project i decided t use NTRIP without my own base. As i can tell this worked well.

I have do try the setup with my one base another time.

Thank you for your help.

Benjamin


(Marlon Guaman Jaramillo) #7

I had a concern very similar to this, only that in my case calculate the height of the ellipsoid from the ortometrical height, I have not had problems, there are programs for that on the web. My query is more about which Geoide model can be used in EMLID, in my country they use the EGM96 and EGM08. I can place my base in a known coordinate using these geoids or I must necessarily use the geoid EGM84.

Tenia un inquietud muy parecida a esta, solo que en mi caso calcular la altura del elipsoidal a partir de la altura ortometrica, no he tenido problemas, hay programas para eso en la web. Mi consulta es mas acerca de que modelo de Geoide se puede usar en EMLID, en mi país usan el EGM96 y EGM08. Puedo colocar mi base en una coordenada conocida usando estos geoides o necesariamente debo usar el geoide EGM84.


(Andrew Yushkevich) #9

Hi @marlonfgj,

At the moment, ReachView uses EGM96 model for the base coordinate height value.
So, you can use your known base coordinates without any issues.


(Hunter) #10

In the survey export files wouldn’t the height be based on the EGM96 model then?