I don't know what "hdop" is but your comment is basically the same as what I was told by Yuneec CS back in March:After the initial calibration and library loadout of the GPS unit,...
I see no reason for this (bold). If GPS locks and hdop is good, I go.
"Please simply perform a compass calibration on your unit whenever you are preparing to fly in a new location over 200 miles from the previous flight. After this is completed and the unit states Ready in the GPS field you are good to go!" and:
"Simply perform the GPS [he obviously meant compass] calibrations following large moves (over 200 miles) or severe weather changes to be safe."
"Severe weather changes" is a new one to me.