I am attempting flights that are originating from a locale rich in magnetic interference. I cannot avoid the environs and the source of the metal is a lot of rebar in concrete and steel plating (a simulated ship deck). All of it is at, or below ground level.

I can find a gravel area off to the side to calibrate the compass, but when I relocate to my desired base of operations and homepoint, I'm in the thick of it..... at least at ground level. When the P3 is held about 4 or 5 feet above the ground, my GPS locks in and everything looks great.

I have a workaround for my landings. I have practiced a  catch-retrieval with colleague.... so once airborne, the P3 will never  get closer than 8 to 10 feet from the ground.

My question is... so long as I achieve a good compass calibration and maintain a safe altitude above the ground, should my GPS and navigation be trustworthy?

The metal in the concrete will not have any effect on the GPS signal, the only effect is upon the compass. If you achieve a good compass calibration well away from the concrete or any other metal, it will be OK to fly with.

Geebax Posted at 2016-4-21 19:42
The metal in the concrete will not have any effect on the GPS signal, the only effect is upon the co ...

Thanks Geebax.... that was my guess. I appreciate the feedback.