Can anyone help me to integrate the PX4 flow sensor with the pixhawk running px4. On my parameter i have messed with ekf_aid and sens_rotation and I have enabled the ultrasonic sensor tab on qground control. On my analyse option i can see the movements created by the drone as well range. I am currently using the pixhawk and the Px4 flow with the ultrasonic is connected by 12c and USART. It is showing me all of this data but it cant comprehend it as it denies altitude mode without GPS and doesnt let me test it. Outdoors in altitude its giving very similar results to that of the altitude hold possible with GPS.