GPR Surveying and Terrain Following

Hi,

I’m looking for a solution for flight planning and using basemaps for terrain following. Are such applications possible with Pixhawk?

I also want to fly very low as I’ll using a GPR attachment which will require this. Is there a lower limit on altitude in the App?

Also, do I need to purchase a hardware unit for the drone to make all of this possible?

Looking forward to a response.

Best,

Niall

Does no-one have experience with this? I would like to do this too.
If one wants to fly at 1m, what rangefinder setting(s) do we need to work with to make this possible?