Setting up SITL on Linux

This page describes how to setup the SITL (Software In The Loop) on Linux. The specific commands were tested on Ubuntu from 12.10 to 16.04.

Overview

The SITL simulator allows you to run Plane, Copter or Rover without any hardware. It is a build of the autopilot code using an ordinary C++ compiler, giving you a native executable that allows you to test the behaviour of the code without hardware.

SITL runs natively on Linux and Windows. See the separate windows installation page for a windows install.

../_images/SITL_Linux.jpg

Install steps

Please follow the instructions in Setting up the Build Environment (Linux/Ubuntu) to set up the full environment, including SITL.

There is also a linked video below showing how to do the setup.

Warning

The video hasn’t been updated according to the text. Please read the written instructions in case of error. For example the video speak about sim_vehicle.sh where it is sim_vehicle.py now.

Start SITL simulator

To start the simulator first change directory to the vehicle directory. For example, for the multicopter code change to ardupilot/ArduCopter:

cd ardupilot/ArduCopter

Then start the simulator using sim_vehicle.py. The first time you run it you should use the -w option to wipe the virtual EEPROM and load the right default parameters for your vehicle.

sim_vehicle.py -w

After the default parameters are loaded you can start the simulator normally. First kill the sim_vehicle.py you are running using Ctrl-C. Then:

sim_vehicle.py --console --map

Tip

sim_vehicle.py has many useful options, ranging from setting the simulation speed through to choosing the initial vehicle location. These can be listed by calling it with the -h flag (and some are demonstrated in Using SITL for ArduPilot Testing).

Tip

If the map titles don’t load, you can temporary change the map provider in the map window by clicking View/Service. To keep the new map service between launch, add the following lines to the end of your “.bashrc” (change MicrosoftHyb by the provider you want):

export MAP_SERVICE="MicrosoftHyb"

Learn MAVProxy

To get the most out of SITL you really need to learn to use MAVProxy. Have a read of the MAVProxy documentation. Enjoy flying!

Using JSBSim

For ArduPlane you can choose several possible simulators. A popular choice is JSBSim, which you can enable with the -f jsbsim option to SITL.

JSBSim is a sophisticated flight simulator that is used as the core flight dynamics system for several well known flight simulation systems.

In the past ArduPilot required a special version of JSBSim. As of December 2018 that is no longer the case, and we can use the standard JSBSim releases.

In order to build JSBSIM, you need Cmake, install it with :

sudo apt-get install cmake

In the same directory (your home directory) run these commands:

git clone git://github.com/JSBSim-Team/jsbsim.git
cd jsbsim
mkdir build
cd build
cmake -DCMAKE_CXX_FLAGS_RELEASE="-O3 -march=native -mtune=native" -DCMAKE_C_FLAGS_RELEASE="-O3 -march=native -mtune=native" -DCMAKE_BUILD_TYPE=Release ..
make -j2

If using the JSBSim plane simulator you can specify a different JSBSim model than the default Rascal110 by specifying the model name using the -f parameter to sim_vehicle.py, like this:

sim_vehicle.py -v ArduPlane -f jsbsim:MyModel --console --map

the model should be in the Tools/autotest/aircraft/ directory.

FlightGear 3D View (Optional)

Developers can optionally install the FlightGear Flight Simulator and use it (in view-only mode) to display a 3D simulation of the vehicle and its surroundings. This provides a much better visualization than the 2D maps and HUD flight displays provided by MAVProxy and Mission Planner.

../_images/flightgear_copter_windows.jpg

FlightGear:Simulated Copter at KSFO (click for larger view).

SITL outputs FlightGear compatible state information on UDP port 5503. We highly recommend you start FlightGear before starting SITL (although this is not a requirement, it has been found to improve stability in some systems).

The main steps (tested on Ubuntu Linux 14.04 LTS) are:

  1. Install FlightGear from the terminal:

    sudo apt-get install flightgear
    
  2. Open a new command prompt and run the appropriate shell file for your vehicle in /ardupilot/Tools/autotest/: fg_plane_view.sh (Plane) and fg_quad_view.sh (Copter).

    This will start FlightGear.

  3. Start SITL in the terminal in the normal way. In this case we’re specifying the start location as San Francisco airport (KSFO) as this is an interesting airport with lots to see:

    sim_vehicle.py -L KSFO
    

    Note

    FlightGear will always initially start by loading scenery at KSFO (this is hard-coded into the batch file) but will switch to the scenery for the simulated location once SITL is started.

Tip

If the vehicle appear to be hovering in space (no
scenery) then FlightGear does not have any scenery files for the selected location. Choose a new location!

You can now takeoff and fly the vehicle as normal for Copter or Plane, observing the vehicle movement including pitch, yaw and roll.

Next steps

After installation, see Using SITL for ArduPilot Testing for guidance on flying and testing with SITL.