Stabilized mode seems not stabilized

I play the UAV first time.

 I found it float up and down in stabilized didn't  level it normal? 
 Haredware is PIXHAWK V2.

Thanks very much.

Log is attached!

in stabilize mode copter should level, but not control position or altitude.
Can you send URL to full log at logmuncher, this three plots is not enough.


  Here is URL of log

 By the way,why the GPOS.Alt is stable,but the aircraft float up and down? are there something wrong with my sensor?

thanks very much

there are few thing
you have to read what fligth modes are what

in stabilize only attitude is stabilize, if you want to stabilise altitude, you have to use ALITUTE CONTROL, If you want to use GPS to maintain position, you have to use position control mode.

another thing is you have to big vibrations in your frame. You have to balance your props. If balancing not help you have to isolate flight controler from this vibrations.