PX4 SITL Drone Not Climbing Above 0.1m During Takeoff

PX4 Autopilot
1

I am running PX4 SITL with Gazebo using the x500 model, but my drone does not climb above 0.1m when executing a takeoff command. The takeoff is detected, but the altitude remains stuck at 0.1m, and the drone does not ascend further.

Here’s what I’ve checked and tried so far:
1. Takeoff Altitude Parameter (MIS_TAKEOFF_ALT)
• Set to 2.5m (param set MIS_TAKEOFF_ALT 2.5)
• Verified with param show MIS_TAKEOFF_ALT
2. EKF2 Status (ekf2 status)
• local position: 1
• global position: 1
• terrain: 1
• However, Preflight Fail: height estimate not stable warning occurs.
3. Sensor Data (listener sensor_combined)
• IMU and accelerometer values appear normal.
• Gyro readings are active.
• However, dist_bottom_valid: False in vehicle_local_position.
• Set to 0 (Barometer) → No improvement.
5. Motor Outputs (listener actuator_outputs)
• Motors are receiving signals and spinning.
• However, thrust does not seem to increase above hover level.
6. Gazebo Physics & Gravity
• gz physics -p confirms gravity is 9.81 m/s².
• gz topic -e /gazebo/default/x500_1/actuators shows actuator commands are being published.
7. Force Manual Climb in Altitude Mode
• commander mode altitude
• commander arm
• commander throttle up
• The drone still does not climb above 0.1m.
8. PX4 Logs & Additional Tests
• PX4 logs show Takeoff detected.
• The drone remains in the “taking off” state but does not exceed 0.1m.

⸻

Question:
• Why is the drone not climbing above 0.1m despite a correct takeoff command?
• How can I resolve the “Preflight Fail: height estimate not stable” warning?
• Could this be a Gazebo-PX4 synchronization issue or a terrain-following problem?

Any insights or debugging suggestions would be greatly appreciated! :rocket:

⸻

Environment:
• PX4 Version: Latest master branch
• OS: Ubuntu 22.04 (WSL2)
• Gazebo Version: Garden
• Simulator Model: x500
• EKF2 Parameters: Default, with some modifications as mentioned above

2

Which x500 model? Which world? What parameters did you change?

I just tested it and it works. Try a clean build (rm -rf build) and run again

make px4_sitl gz_x500

And either takeoff in QGC or nsh command line

commander takeoff
3

Thanks for the response!

I’m using the x500 model in Gazebo, and I’ve made some modifications to the world settings. Here’s what I’ve done so far:
1. Gazebo World Modifications:

•	Configured SIM_GZ_HOME_ALT to 0 to prevent altitude mismatch issues.

2.	Spawned Two x500 Drones at Different Locations:
model://x500 x500_1 0 1 0.2 0 0 0 model://x500 x500_2 5 5 0.2 0 0 0 
3.	Start Command for Each Drone:

PX4_SYS_AUTOSTART=4001 PX4_GZ_MODEL_NAME=“x500_1” PX4_GZ_MODEL_POSE=“0,1,0.2” PX4_SIM_MODEL=x500 ./build/px4_sitl_default/bin/px4 -i 1
PX4_SYS_AUTOSTART=4001 PX4_GZ_MODEL_NAME=“x500_2” PX4_GZ_MODEL_POSE=“5,5,0.2” PX4_SIM_MODEL=x500 ./build/px4_sitl_default/bin/px4 -i 2 &

4.	Issue:
•	The drone detects takeoff but does not climb above 0.1m.
•	Preflight Fail: height estimate not stable warning appears.
•	listener vehicle_local_position shows dist_bottom_valid: False.

Would really appreciate any insights on why the takeoff is limited to 0.1m and how to stabilize height estimation

1 Like
4

You’re not launching the sim correctly, please see the docs

Also the default branch is main not master so make sure you’re using main.