SITL with Simulink Interface

Hi guys,

Just a quick question about where to find SITL interfaces with a simulink model? e.g. I want to use the control law inside arduplane codes so the AP interfaces sends servo channel pwm/control surfaces commands/throttle command so that I can feed them into simulink aerodynamics/ plant model to send states back to SITL. Essenstially where can I find defintion and determine what command is being sent into the json interface with the simulink model?

Thanks in advance.

I follow this link, but is says that, waiting for connection
MATLAB Simulation — Dev documentation (ardupilot.org)