jMAVSim with SITL
jMAVSim is a simple multirotor/Quad simulator that allows you to fly copter type vehicles running PX4 around a simulated world. It is easy to set up and can be used to test that your vehicle can take off, fly, land, and responds appropriately to various fail conditions (e.g. GPS failure).
This topic shows how to set up jMAVSim to connect with a SITL version of PX4.
jMAVSim can also be used for HITL Simulation (as shown here).
Software in the Loop Simulation runs the complete system on the host machine and simulates the autopilot. It connects via local network to the simulator. The setup looks like this:
After ensuring that the simulation prerequisites are installed on the system, just launch: The convenience make target will compile the POSIX host build and run the simulation.
make posix_sitl_default jmavsim
This will bring up the PX4 shell:
[init] shell id: 140735313310464 [init] task name: px4 ______ __ __ ___ | ___ \ \ \ / / / | | |_/ / \ V / / /| | | __/ / \ / /_| | | | / /^\ \ \___ | \_| \/ \/ |_/ Ready to fly. pxh>
It will also bring up a window showing a 3D view of the jMAVSim simulator:
Taking it to the Sky
The system will start printing status information. You will be able to start flying once you have a position lock (shortly after the console displays the message: EKF commencing GPS fusion).
To takeoff enter the following into the console:
pxh> commander takeoff
You can use QGroundControl to fly a mission or to connect to a joystick.
Set Custom Takeoff Location
The default takeoff location in can be overridden using the environment variables:
For example, to set the latitude, longitude and altitude:
export PX4_HOME_LAT=28.452386 export PX4_HOME_LON=-13.867138 export PX4_HOME_ALT=28.5 make posix_sitl_default jmavsim
Using a Joystick
Joystick and thumb-joystick support are supported through QGroundControl (setup instructions here).
Simulating a Wifi Drone
There is a special target to simulate a drone connected via Wifi on the local network:
make broadcast jmavsim
The simulator broadcasts its address on the local network as a real drone would do.
Extending and Customizing
To extend or customize the simulation interface, edit the files in the Tools/jMAVSim folder. The code can be accessed through thejMAVSim repository on Github.
The build system enforces the correct submodule to be checked out for all dependencies, including the simulator. It will not overwrite changes in files in the directory, however, when these changes are committed the submodule needs to be registered in the Firmware repo with the new commit hash. To do so,
git add Tools/jMAVSimand commit the change. This will update the GIT hash of the simulator.
Interfacing to ROS
The simulation can be interfaced to ROS the same way as onboard a real vehicle.
- The startup script is in the posix-configs/SITL/init folder and named
rcS_SIM_AIRFRAME, the default is
- The root file system (the equivalent of
/as seen by the) is located inside the build directory: