We just started to use the OF camera (https://pixhawk.org/modules/px4flow).
We have successfully installed all the packages needed to run it on ROS (px4flow_node - ROS Wiki). Though the camera works OK, we can see actual video, it seems that the ultrasound sensor does not (“ground_distance: 0.0”). I got this message after displaying the topic: rostopic echo /px4flow/opt_flow. I have tried to figure out a solution, but when we use a second camera, we get the same result. Because of this, the velocity is also zero (“velocity_x” and “velocity_y” messages).
Could you kindly advise us a solution? thank you very much indeed.