Gazebo Jetty

In this section, we will explain how to install and setup Gazebo Jetty and PX4-Autopilot for performing simulations with pegasus. This was tested on Ubuntu 24.04.

Installing Gazebo Jetty

Follow the installation steps provided in the official Gazebo Jetty documentation: Gazebo Jetty Installation Guide, which are provided here for convenience:

# Install the necessary tools
sudo apt-get update
sudo apt-get install curl lsb-release gnupg

# Install gazebo (jetty)
sudo curl https://packages.osrfoundation.org/gazebo.gpg --output /usr/share/keyrings/pkgs-osrf-archive-keyring.gpg
echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/pkgs-osrf-archive-keyring.gpg] https://packages.osrfoundation.org/gazebo/ubuntu-stable $(lsb_release -cs) main" | sudo tee /etc/apt/sources.list.d/gazebo-stable.list > /dev/null
sudo apt-get update
sudo apt-get install gz-jetty

# Make sure multicast is enabled on your network interface
sudo ufw allow in proto udp to 224.0.0.0/4
sudo ufw allow in proto udp from 224.0.0.0/4

# Install ROS 2 Jazzy packages for Gazebo
sudo apt install ros-jazzy-ros-gz ros-jazzy-ros-gz-image
sudo ldconfig

Installing PX4-Autopilot

In this first version of the Pegasus the PX4-Autopilot is used for handling motor control and sensor integration. To install PX4-Autopilot, follow the following steps:

1. Install the dependencies (to be able to compile PX4-Autopilot):

   # Linux packages
   sudo apt install git make cmake python3-pip
   
   # Python packages
   pip install kconfiglib jinja2 empy==3.3.4 jsonschema pyros-genmsg packaging toml numpy future
   
   # GStreamer (for video streaming)
   sudo apt-get install libgstreamer-plugins-base1.0-dev gstreamer1.0-plugins-bad gstreamer1.0-plugins-base gstreamer1.0-plugins-good gstreamer1.0-plugins-ugly -y
   

2. Clone the PX4-Autopilot:

   # Option 1: With HTTPS
   git clone https://github.com/PX4/PX4-Autopilot.git
   # Option 2: With SSH (you need to setup a github account with ssh keys)
   git clone git@github.com:PX4/PX4-Autopilot.git
   

3. Checkout to the stable version 1.16.1 and compile the code for software-in-the-loop (SITL) mode:

   # Go to the PX4 directory
   cd PX4-Autopilot
   
   # Checkout to the latest stable release
   git checkout v1.16.1
   
   # Export the compilers (important if using python conda environments)
   export CXX=g++
   export CC=gcc
   
   # Compile the code in SITL mode
   make px4_sitl_default
   

4. Add the following line to your .bashrc file:

   echo "export PX4_DIR=$(pwd)" >> ~/.bashrc
   

   Note

   Adding this line to the .bashrc file is important as the Pegasus Gazebo package will need to know the location of the PX4-Autopilot directory, and the launch files will use this environment variable to find the necessary files.

Standards

When creating a new sdf world for Gazebo, make sure to follow the standard below for the world name “”simulation_world””.

<?xml version="1.0"?>
<sdf version="1.9">
    <world name="simulation_world">
        ...
    </world>
</sdf>

To avoid having to change the world name in multiple places, we standardize the world name to be always “simulation_world”. This is standard across all the pegasus worlds, because in the launch files we must speficy the world name such that PX4-Autopilot can subscribe to the gz topics correctly, and interface with the simulator.