HIL not working

Hello everybody, during the last days I tried to setup the HIL with my pixhawk. So far I tried:
-python HIL repo from github but I didn’t find where to get the kalman_demo app to start
-mavproxy+jsbsim, no GPS fix
-changing one parameter about GPS and HIL, no effect
-qgroundcontrol+xplane, no GPS and I can’t switch to mission mode at all.
-I used for the tests the stable version of the PX4 stack uploaded from qgroundcontrol and I have also compiled and uploaded the v1.3.3 by myself but without improvements

I always have GPS fix problems, I followed carefully the PX4 dev guide and I also tried with the qgroundcontrol procedure published online. I worked with the pixhawk connected via USB on linux.

Do you guys have any working procedure to suggest? I need to solve it. Thank you!