Hello,

I have got a new Phantom 4 RTK with D-RTK 2 Mobile station. I have done the starting set-up and was testing for the values I am getting.
The Lattitude and the Longitude values are correct for my location but the Altitude value I am getting is 17meters. Whereas, I am located at an altitude of 69 meters above mean sea level.

Please share your ideas related to this which can be helpful to solve my issue.

Thanks

Your altitude is going to be relative to the WGS84 ellispoid (HAE or Height Above Ellipsoid), not MSL. Sounds like the difference between MSL and the ellipsoid in your location is about 52 meters....

patiam Posted at 3-25 08:40
Your altitude is going to be relative to the WGS84 ellispoid (HAE or Height Above Ellipsoid), not MSL. Sounds like the difference between MSL and the ellipsoid in your location is about 52 meters....

Thanks for your quick response.

Okay.

My MSL is 53 meters and the top of my building from the ground is 15 meters. So, overall the output should be 68 to 70 meters approx.

What are the settings need to be done in Drone/ D-RTK Mobile station in order to get the altitude in terms of Above Sea Level?

hardrone Posted at 3-25 21:00
Thanks for your quick response.

Okay.

GPS coordinates are (usually) generated as geographic (Lat/Lon) values relative the the WGS1984 datum for XY, and in Height Above Ellipsoid for Z.
When you enter the coordinates for your  D-RTK 2 base station location you should be entering them as such.
If you want your Z to be in MSL then find the difference between HAE and MSL using EGM96, or another model.
If none of this makes sense then you should learn about geodesy before you expect to use precision GPS gear to generate accurate survey results.

Hello again,

I got your that point.

The other issue I forgot to mention is, I am getting altitude variation even according to HAE. Once it shows 10m, then 12m and later it was showing 15 meters.
Each time there was connection between RC, Drone and RTK-2 Mobile Station.
The setup location of RTK -2 Mobile Station was same for all the time.  

If it is due to firmware issue or what, I do not understand that.

Even there is something wrong with the firmware up-gradation. It is not even showing me the current firmware version when connecting D-RTK through USB C with RC. It is not showing any firmware to upgrade - in display app. and I am not able to upgrade it using DJI Assistant 2.

Please let me know if someone has gone through this issue.