my spark used to get a imu needs calibrating error, but then i wait and the error goes, one day i need to try calibrating the imu and compas, but i don't know how to lol,
plus i never have a flat level surface, i know, but its true.
i figure the spark will calibrate itself during hover, it can work it out what way is north, what way is level etc etc.
thats why i got it, its got intel inside.

I keep getting the message my compass needs to be calibrated but when I go into the menu it says normal and wont let me calibrate. It's very frustrating. How do I fix this issue. Also I get no satellites but says GPS is good.

I seriously only calibrated it at the beginning. Now im using it for 1 year without any calibration and see there its working great.
Depends on how intensive you are flying

only do it when the app says I should.