The issue is much more likely due to the limitations of the VPS system when dealing with a 3-dimensional mess of leaves and thin branches, rather than a simple solid surface.I believe the system failed because, regardless of the barometric pressure, the purpose of the VPS is to prevent crashes, and the sensors should recognize obstacles and halt the descent. If it indeed recognized the obstacle 5.4 meters below, there should have been enough time to stop the drone.
Observe the height on your screen when you move the drone up and down just small distances.The problem lies in the fact that the data log shows a vertical speed of zero, yet the drone was still descending.
You explained that vertical speed is calculated from barometric pressure. If the speed is based on barometric pressure and it indicates that the drone is not descending, but in reality, the drone is still descending, then the algorithm is incorrect because it relies on inaccurate or unreliable data.
It senses small changes in height quite accurately.
Your VPS data showed that it didn't pick up the vegetation until it was just 5.4 metres away.I believe that once an obstacle is recognized, the drone should come to a stop and prompt the operator for further instructions.
That's just half the distance it could read the ground after you launched.
Obstacle avoidance and VPS are not magic and cannot work perfectly in every situation.
The manual lists a number of situations that can make things difficult for the sensors.
Particularly note the last one.
The Vision Systems cannot work properly over surfaces without clear pattern variations or where the
light is too weak or too strong. The Vision Systems cannot work properly in the following situations:
a) Flying over monochrome surfaces (e.g., pure black, white, red, or green).
b) Flying over highly reflective surfaces.
c) Flying over water or transparent surfaces.
d) Flying over moving surfaces or objects.
e) Flying in an area with frequent and drastic lighting changes.
f) Flying over extremely dark (< 10 lux) or bright (> 40,000 lux) surfaces.
g) Flying over surfaces that strongly reflect or absorb infrared waves (e.g., mirrors).
h) Flying over surfaces without clear patterns or texture (e.g., power poles).
i) Flying over surfaces with repeating identical patterns or texture (e.g., tiles with the same design).
j) Flying over obstacles with small surface areas (e.g., tree branches