Drone crash due to gps switching

My quadcopter flies well initially but in mid air it starts twitching and then crases. I checked log and there was error “gps unknown” and gps2 unknown. I have only one gps in my drone. Is it that gps is switching from gps1 to gps2.

  i have added the link to logs here. Can someone have a look in logs and help me with the bug.

link: https://drive.google.com/open?id=11X1aNtBOiJ0rLK0I1IUkcF7GVFSa7mCZ
Appreciate the help.

The errors that you saw were GPS Glitch detection. It seems the GPS reception went down in flight.