MAVSIMNET is a simulation framework for the OMNeT++ discrete event simulator based on Ardupilot's Software In The Loop (SITL) simulator. It allows you to enrich OMNeT++ and INET's simulations with realistic mobility models for the mobile nodes in your network. It works by spawning SITL instances that provide a physical simulation of the vehicle's behaviour and connecting them to the mobility classes in your simulation.
More information can be found on the project's official documentation