I've custom built drone, controlled by Pixhawk (board version 2.8.4), firmware 1.7.3_v3, and I have an issue with hold mode. When drone is take off it automatically enters to hold mode and hovers about launch point. It hovers about 30-40 seconds normally and after that starting moving by expanding spiral which increasing a diameter by every loop. I've tried different types of GPS receiver but it doesn't help.
Can anyone help me?