We have been testing a quadcopter in the offboard mode indoors and outdoors with the following configuration:
Flight controller: Pixhawk v2 with PX4 in NuttX configuration.
Off-board Machine: Ubuntu Intel i7 Laptop with ROS kinetic (connected with Flight controller by telemetry 915MHz)
HW arch: PX4FMU_V2
FW git-hash: f7f47fe6b26d95d811279cf0b416be29912aa33b
FW version: v1.5.1-5-gf7f47fe (1.5.1 0), 17105152
OS version: 6.27 (100796415)
Build datetime: Dec 18 2016 12:12:06
Toolchain: 4.9.3 20150529 (release) [ARM/embedded-4_9-branch revision 227977]
MCU: STM32F42x, rev. 3
Right now, we are just testing the z movement of the drone by using mavros setpoint local position pose. So basically we just ask it to go to a desired height of say 2-3 m and loiter there. While indoors, i.e. without GPS, it works fine.
When outdoors the drone goes completely haywire every once in a while. It drifts really fast and uncontrollably.
We also noticed, during post flight analysis, that every time this has happened, the drone modes changed to either position control or altitude control on its own from offboard mode.
What could be the possible reasons for this? Shouldn’t the flight be more reliable in GPS enabled environment?
Please find the charts and logs on the below links: