SITL with JSON interface asynchronous

Hello guys,

I am trying to communicate with ardupilot in sitl using JSON interface, I have my own physics backend.
My main issue is that my physics solver isn’t fast enough to work with ardupilot in real time so ideally I would have an asynchronous simulation (I think). I think I am sending everything correctly to ardupilot and I manage to pass some of the pre arm checks up to a point where I have home set and everything. However sometimes it appears link 1 down so I am never able to arm…
Is there a way to change the ardupilot code in order to make it wait for my new input through JSON interface without it disconnecting? If you guys could point me where and how to do it it would be great.
If you guys think of a better solution to my problem I would also be able to explore it.

Thank you in advance