"ekf2 stop" get stuck in SITL

[airopti]

Describe the bug
I am running SITL, when trying to stop the EKF by ekf2 stop, the Gazebo simulation get stuck and there is no any feedback information.

System

• Ubuntu 16.04
• ROS Kinetic
• Gazebo 9

To Reproduce
Steps to reproduce the behavior:

1. roslaunch px4 mavros_posix_sitl.launch
2. After started the Gazebo simulation, run ekf2 status, can get some feedback
3. But, when run ekf2 stop, the simulation get stuck and there is no any feedback information.

• log file
• I have tried Gazebo 7 , 8 and 9, but they all get stuck when running ekf2 stop

[dagar]

@airopti this is because by default PX4 SITL is running lockstep with the simulator, which means simulated sensor data making a round trip through the system and back out as actuator controls.
One of the mechanisms for ensuring nothing is missed is the simulator interface waiting for the estimator to run on each new IMU sample.

[airopti]

But the waiting time seems to be infinite, it just get stuck there, is it normal?

[julianoes]

@airopti yes that's expected.

Alternatively, you can try without lockstep (see https://dev.px4.io/master/en/simulation/#disable-lockstep-simulation).

[airopti]

Thank you so much, this solved my problem.