iphone photo gps coordinata mistake

My problem is, if my iphone is sleep a long time, and i wake up and make photos, the saved gps coordinate is sometime miss about 5-20 km

Why i can't see when perfect the gps coordinate?

Or why repair the coordinate if the iphone see i am not moveing and replace the wrong gps coordinate to the real and good coordinate?

(sorry my english is not soo good)