Hi Everyone,

I'm using the P4RTK for some time now.
My mine interrest in using it was not to place GCPs in small construction sites for a faster workflow.

Unfortunately I get Z discrepancies from 30 up to 45 metres.

I'm using Pix4d with their suggested workflow for creating my 3d maps.

Has anyone a clue, why there is such a big vertical difference and how can I take this into account to compensate withough gcps?

Greetings from bavaria

quintz

Can you explain what you mean by "Z discrepancies"? Is your entire DSM off by 30-45 m? What vertical datum are you using and how are you managing that in Pix4D?

patiam Posted at 11-12 11:00
Can you explain what you mean by "Z discrepancies"? Is your entire DSM off by 30-45 m? What vertical datum are you using and how are you managing that in Pix4D?

Sorry for the late reply!

Yes, my whole project is lifted by a given amount.

I bought my drone from droneparts.de and they have a FAQ regarding some questions other customers had about the P4RTK. The DJI Support there answered:

FAQ: Deviation of 0.96 m in X, approx. 2.6 m in Y and 47 m in Z**_ DJI support answer: Looks like the customer using an wrong coordinate system or he doing some transformations. We are using WGS 84, ellipsoid height. Customer must use the same, otherwise he get big offset deviation.

As recommended I'm using WGS 84 / UTM Zone 32N for my region.