[mavros_posix_sitl.launch] is neither a launch file in package [px4] nor is [px4] a launch file name

[AlexWUrobot]

When running

roslaunch px4 mavros_posix_sitl.launch

MAVROS Offboard control example (Python) | PX4 User Guide

It cannot find the px4

However, the tutorial told us to add the .bashrc file

I notice the newest PX4-Autopilot change the setup_gazebo.bash into the folder gazebo-classic/

Thus, you have to manually change the path to gazebo/ to gazebo-classic/ like the below picture
you can just use bash, instead of zsh. The reason why I use zsh is just for recording commands

Although changed the source and export, it can find px4 but still cannot find other source

Then, I try to add the below line into .zshrc file

export ROS_PACKAGE_PATH=$ROS_PACKAGE_PATH:~/Firmware/Tools/sitl_gazebo

Resource not found: The following package was not found in <arg default="$(find mavlink_sitl_gazebo)/worlds/empty.world" name="world"/>: mavlink_sitl_gazebo

Then, it can run roslaunch px4 mavros_posix_sitl.launch but shows an error

Some people have the similar issue and cannot find the source

Unable to launch script

https://answers.gazebosim.org//question/24761/ros1gazebo-2-segfault-for-exit-code-139/

[AlexWUrobot]

Last, I find an solution by source file , according to this ROS with Gazebo Simulation | PX4 User Guide

but I need to do some modification to run it , like below screenshot
The reason is the latest PX4-autopilot change its gazebo folder name into gazebo-classic

source Tools/simulation/gazebo-classic/setup_gazebo.bash $(pwd) $(pwd)/build/px4_sitl_default
export ROS_PACKAGE_PATH=$ROS_PACKAGE_PATH:$(pwd)
export ROS_PACKAGE_PATH=$ROS_PACKAGE_PATH:$(pwd)/Tools/simulation/gazebo-classic/sitl_gazebo-classic

My platform is ubuntu 18.04 and python version is 3.6.9

[AlexWUrobot]

Then, I can successfully run

roslaunch px4 mavros_posix_sitl.launch

and

rostopic echo /mavros/imu/data

[AlexWUrobot]

roslaunch px4 mavros_posix_sitl.launch

follows 2 small error.
One is Error [Converter.cc:151] Unable to convert from SDF version 1.7 to 1.6

https://answers.gazebosim.org//question/7691/unable-to-convert-from-sdf-version-15-to-14/

I solved it by editing sdf file version from 1.7 to 1.6

The other error is

[ERROR] [1674526819.464722103, 51.024000000]: TM : Time jump detected. Resetting time synchroniser.

TM : Time jump detected. Resetting time synchroniser

Mavlink Time sync

Hi, I’m looking for guidance on how time sync with mavlink message are handle. I’m running gazebo sitl with mavros and I’m getting alot of these messages: ERROR [mavlink] [timesync] Time jump detected. Resetting time synchroniser. in the px4 console.

There is warning about too many subscription

WARN  [logger] Too many subscriptions, failed to add: estimator_aid_src_ev_vel 5

Logger complains about too many subscriptions