Servers by jDrones

Auto Grid Following Problem

We are using pixhawk cube for mapping and we deploy the auto grid mission in it and we are using song alpha 6000 for capturing images. During the auto survey grid mission plane follows the straight line exactly as we have given but on the verge of turning it overshoots and come back to the straight line. We just want to know what may be the factor that allows the plane to overshoot.
pls, help us.
Thanks in advance
Telemetry log.
https://drive.google.com/open?id=1bHbMBqDkMkM0hNdSf0E7EwZkQW02unjx

Servers by jDrones