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UAV Ops Notes

Operational notes for common bringup and troubleshooting cases.

VTOL Fixed-Wing / QGC

When launching VTOL in fixed-wing mode, make sure these PX4 parameters are set in QGC:

  • CBRK_VTOLARMING = 159753
  • FW_W_EN = 1
  • RWTO_TKOFF = 1
  • NAV_FORCE_VT = 0

If you want to make that permanent in sim, add these lines to ~/PX4-Autopilot/ROMFS/px4fmu_common/init.d-posix/airframes/4004_gz_standard_vtol:

param set-default CBRK_VTOLARMING 159753
param set-default FW_W_EN 1
param set-default RWTO_TKOFF 1
param set-default NAV_FORCE_VT 0

Troubleshooting

AprilTag missions fail immediately or no detector is available

Install the runtime Python dependencies on the machine running the vision nodes:

python3 -m pip install "pydantic>=2,<3" apriltag

auto_launch: false and the mission never starts

This is expected. The stack still launches, but the mission stays idle until /<vehicle>/mode_manager/start_mission is called. This applies to both UAV and payload missions.

ros2 service call /<vehicle>/mode_manager/start_mission std_srvs/srv/Trigger "{}"

Sim came up headless or with the wrong GUI mode

GUI is the default. Either of these forces headless mode:

  • SAE_SIM_GUI=0
  • SAE_SIM_HEADLESS=1

Payload hardware issues

For pigpiod, GPIOController, and payload hardware bringup details, use payload/README.md.