Position hold and Qgroundcontrol

Hello all, I am newbie… Now I am facing a problem.

Details of hardware : pixhawk 4 , It’s gps. Frame size 650mm … No canopy used or no cover is used to cover pixhawk…

  1. Problem : when I put it into position hold… It hold that position for few seconds after that it suddenly rise and suddenly down and move side ways without my input. No of connection of satellite 11 . Precision about 0.9m ( GHDOP).

And also there is another problem too. When I arm drone through QGC it automatically started to ascend … And again suddenly rise and down and same problem above… (Problem 1).

I add log file in this… Why my drone is not hold its position.

Log file

https://drive.google.com/file/d/17aogvs6CkEE57higRPfjs5KlIrkeLsDD/view?usp=drivesdk

Hope you understand… If any doubt in my question please ask…