This repo hosts gazebo worlds for various drone scenarios and various drone configurations. This Repo is specifically designed to work with the Ardupilot control system, and utilizes the ardupilot gazebo plugin to allow the ardupilot control software to interface and control the model drone in gazebo.
take a look at these tutorials to setup ardupilot, gazebo and the ardupilot gazebo plugin
Installing Ardupilot and MAVProxy
Installing Gazebo and ArduPilot Plugin
Installing x-term is recommended as it allows the ardupilot sitl interface to run in a terminal that will cleanly close when closing you sitl instance
sudo apt install x-term
Recently I have been experimenting with Ardurover for controlling an autonomous boat. Bellow shows the steps for installing for boat simulation. If you have already installed for quadcopter simulation, then most of the boat installation should already be completed.
First terminal
roslaunch iq_sim boat.launch
second terminal
sim_vehicle.py -v APMrover2 -f gazebo-rover -m --mav10 --console -L Viridian