Magnetic Field Interference

[FlyingBusman]

Today I was over a corn field in an area with no hills or obstructions for 2 miles in every direction and not near any buildings. I got three warnings in one minute for weak GPS and then a Magnetic Field Interference warning and my Phantom started flying in a very unstable way. Thankfully I was able to get it down without a crash but had I been next to buildings or people I’m afraid of what might have happened. My drone is an Obsidian Phantom 4 Pro +. I’m not sure if it needs to be sent in for repairs or what to do. I’m definitely reluctant to put it back into the air. I have never had any gps problems here and I had been flying for about 20 minutes before the incident occurred. Hopefully you guys can help me out. Thank you

 

[FlyingBusman]

I have had similar strange behaviour flying in certain locations. Whilst certain atmospheric conditions can cause temporary GPS loss I have found that flying in areas with rich iron ore deposits can really screw with the compass and GPS. My simple solution was to fly for the short piece of footage I wanted in non GPS mode. Not the ideal for many but I consider myself a pretty competent pilot so I wasn’t overly concerned. Try flying in a new location some distance away and see how you go. I feel you may just have had a one off event.

 

[Meta4]

Whilst certain atmospheric conditions can cause temporary GPS loss

GPS is designed to be an all-weather navigation system.
Weather conditions would have to be cataclysmic to cause GPS loss.
I suspect the actual cause of what you observed was something else.

I have found that flying in areas with rich iron ore deposits can really screw with the compass and GPS.

While in the sky, it's unlikely that what was in the ground had any impact on your drone.
It sounds like compass interference at your launch point was the cause.