installing-gazebo-ardupilot

sudo sh -c 'echo "deb http://packages.osrfoundation.org/gazebo/ubuntu-stable `lsb_release -cs` main" > /etc/apt/sources.list.d/gazebo-stable.list'
wget http://packages.osrfoundation.org/gazebo.key -O - | sudo apt-key add -
sudo apt update

The plugin we will be using works with gazebo versions 7 to 9. 
We recommend gazebo9 as the new development will append on this version. 
It isn’t available for older versions of Ubuntu though, 
so you may need to use an earlier version depending on your system.

sudo apt install gazebo9 libgazebo9-dev

check the installation by launching Gazebo.

gazebo --verbose

Plugin installation
We will be using khancyr plugin for the following exaplation. 
First clone it somewhere in your home directory.

git clone https://github.com/khancyr/ardupilot_gazebo
cd ardupilot_gazebo
mkdir build
cd build
cmake ..
make -j4

Modify the -j flag according to your processor. 
If you do not know the number of cores in your processor, 
you can find it by typing nproc.

sudo make install

echo 'source /usr/share/gazebo/setup.sh' >> ~/.bashrc

echo 'export GAZEBO_MODEL_PATH=~/ardupilot_gazebo/models' >> ~/.bashrc

. ~/.bashrc

Run Simulator
gazebo --verbose ~/ardupilot_gazebo/worlds/iris_arducopter_runway.world 

launch SITL
launch sitl in other terminal

 cd ~/ardupilot/ArduCopter/
 sim_vehicle.py -v ArduCopter -f gazebo-iris --console