I can't see OBSTACLE_DISTANCE on QGC

rogerli · 25 Feb 2024, 18:44

I only connected UART and GND, and VOXL2 is only connected to the Cube Orange+, a WiFi dongle, and a stereo camera.

I can use the "listener obstacle_distance" command on QGC's MAVLink console to obtain depth information about obstacles, and I have successfully enabled collision prevention for the drone in position mode. However, I still cannot see "obstacle_distance" on the MAVLink inspector.

Eric Katzfey · 26 Feb 2024, 16:59

@rogerli What messages do you see in mavlink inspector?

rogerli · 11 Mar 2024, 08:05

@Eric-Katzfey said in I can't see OBSTACLE_DISTANCE on QGC:

mavlink inspector

This is the messages I see in the MAVLink inspector.

Eric Katzfey · 12 Mar 2024, 02:20

@rogerli The OBSTACLE_DISTANCE Mavlink message is based on the obstacle_distance_fused topic. Can you do listener on that topic to see if it is being published?

rogerli · 18 Mar 2024, 03:51

@Eric-Katzfey said in I can't see OBSTACLE_DISTANCE on QGC:

No, I am unable to use the listener command to see the obstacle_distance_fused message. How can I enable this feature?

Eric Katzfey · 3 Apr 2025, 02:21

@rogerli What is the parameter CP_DIST set to?

Inverse AJ · 3 Apr 2025, 02:32

@Eric-Katzfey I am having a similar problem, where I can see obstacle_distance, but not obstacle_distance_fused using the listener command. When I checked CP_DIST it was set to -1 so I set it to 1 and then I could briefly see both with the listener command, and was able to see obstacle_distance using the mavlink inspector. After unplugging then replugging in my pixhawk, this was gone and I was back to only being able to see obstacle_distance with the listener command. Was there something that could've changed during my restart? I checked CP_DIST and it was still set to 1 even afterwards.

The only notable differences between my system and the original users is that my connection is across ethernet.

Eric Katzfey · 3 Apr 2025, 17:02

@Inverse-AJ A quick look at the code shows that CP_DIST has to be greater than 0 and current flight mode has to be manual position mode. What flight mode are you in?

Inverse AJ · 8 Apr 2025, 01:29

@Eric-Katzfey I was previously in "Hold" mode, but I tried in "manual" and still am not seeing the obstacle_distance_fused message. I noticed one other difference in my parameters which is that COM_OBS_AVOID doesn't exist for me.

Another question, I had previously re-flashed the Pixhawk firmware after changing the file: "PX4Autopilot/src/modules/uxrce_dds_client/dds_topics.yaml". I had added the following to the publications section:

topic: /fmu/out/obstacle_distance_fused
type: px4_msgs::msg::ObstacleDistance

However, it had no effect so I reverted back to the default px4 firmware shown on QGC. Is that change necessary to see the message or should I leave the default?

Inverse AJ · 8 Apr 2025, 02:36

@Eric-Katzfey Small update. I also tried it with the custom firmware with that additional publication added (from previous reply), and the result has not changed. obstacle_distance_fused still shows up as "never published" when using the listener. However, with the custom firmware I get warnings from QGC about missing parameters: BAT1_V_LOAD_DROP, BAT2_V_LOAD_DROP, and COM_OBS_AVOID. I pulled the most recent main branch for the PX4 Repository to build it, so maybe there's not support by QGC yet?

Eric Katzfey · 8 Apr 2025, 15:49

@Inverse-AJ Have you asked this question on PX4 forum? https://discuss.px4.io/c/px4/25

Inverse AJ · 9 Apr 2025, 20:42

@Eric-Katzfey I had not since this discussion was the closest I could find to my issue. But I have created one now: Cannot see obstacle_distance_fused on QGC