we are using the Pixhawk 4 (1.9-beta Firmware) with PX4Flow and Lidar Lite V3. We focused the lens at 1.5m.
Unfortunately, this setup works only under very specific conditions. This means, if we fly a litte higher or lower then 1.5m, all flow values become zero. Furthermore, we get only nonzero flow values if we fly over a surface with structure (see Image 1). If we fly over a flat surface with only texture, we also get no flow data. What could be the problem?
Image 1: If we fly over this surface, we get flow data, but only at 1.5m height
Image 2: If we fly over this surface, we get no flow data