I just purchased an H520 E and was about to conduct a maiden flight and got this error message also. I know how the H520 is so temperamental and have had 2 mishaps with it. I abandoned the flight and packed it back up. Can anyone tell me what this means and how to ensure i have enough GPS to fly in angle mode. I am flying near a cell tower would that cause this issue with controls? The weather was cold and cloudy today.