PX4 Community Q&A: March 15, 2023

March 15, 2023

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  • Community Announcement
  • Community Q&A
  • General Discussions

:loudspeaker: Community Announcement

A.1: PX4 v1.13.3 release!

A.2 : PX4 v1.14 release process is coming

Maintainers are keeping track of release blocker issue / PRs, and once they are resolved, the release/1.4 branch will be branched out of the main branch.

Then the flight testing & bug fixes will continue.

:people_holding_hands: Community Q&A (No deep technical discussions)

:exclamation: Guideline for asking a Question

  1. Specify what you are trying to achieve
  2. Specify what environment / platform you are using
  3. Prepare a Link or Document to help understand if possible
  4. First, ask the question on Discord or create a Github Issue!
  5. If you take over 5 minutes for the question, please continue in Discord or a Github Issue.

Q.1 : Switch from Binary to XML (Data64, Ardupilot Mega MAVLink dialect) - Farhang

Question about since we switched from supporting binary to XML, how to support pre-existing case?

Check out Tunnel message:

Answer: If we want DATA64, let’s get it to a common message set in MAVLink. Also, PX4 never relyed on ardupilotmega dialect. So it’s not a release 1.14 blocker.

Q.2: QGC LAANC support - Andrew

About LAANC:

Idea: In QGC, it would be sending out LAANC request to the FAA and get approval.

If the community is interested in having this in QGC, we can have it contributed (currently planning to have it closed source).

Note: We may want to have arm authorization mechanism between FC & QGC in the implementation as well.

Integration with Airmap: We could be checking before taking off, checking mission plan and check airspace violations, and send LAANC appropriately.

Action Item: Andrew will continue in the integration effort, as no one else seems to be implementing it, and will think about the actual implementation details.

Q.3: NMEA protocol, is it supported in v1.13.3? - Sibu

Using uBlox NEO 6M model. Tried using GPS module with RTK capability, when gps status was executed in MAVLink Console, the lat/lon data were showing. But, it showed “GPS not ok”.

Action Item: Sibu will DM ramon & discuss with Julian furthermore.

Q.4: ROS2 connection & Docker image update - captain_egypt

What is this newest release actually compatible with? It’s not straightforward.

Also, using Simulation with Docker.

Answer: v1.13.3 supports MicroRTPS. But starting from v1.14, only the XRCE-DDS will be supported.

Answer: ROS2 is by default with Foxy (classic Gazebo, Ubuntu 20). But if you are starting from scratch, start with Ubuntu 22.04 & Gazebo garden.

Action Item: Beniamino will reply to docker sim question. Thread is here: Discord

Q.5: Multi vehicle simulation not working with Gazebo classic

Following: Multi-Vehicle Simulation with Gazebo Classic | PX4 User Guide, the multi vehicle sim is not working.

Answer: The RTPS part is what’s not updated.

Note: We didn’t maintain it properly so it is outdated. We should get it captured in the CI to detect if it works or not.

Note: Also, roslaunch based PX4 instance launching is broken since ROS2 adaptation - Daniel

Action Item: Along with updating the documentation, let’s put the CI support for checking if this works - Beniamino

Action Item: Figuring out support level & CI testing coverage with Hamish (Junwoo will organize meeting regarding Jenkins broken state meeting along with Daniel to discuss this)

Q.6: Swarm drone support - Aly (Captain Egypt) :pirate_flag:

For agriculture, trying to use ROS to do swarm control.

Answer: With ROS, you could technically do swarm control however you want - Beniamino

:thinking: General Discussions

D.1 : CHANGE_SPEED command discussion - Andrew

Discussion about how the ‘DO_CHANGE_SPEED’ command should apply. Does current implementation make sense?

Answer: Depending on whether you are in the mission or not should be considered. There are caveats not considered in MAVLink definition.

D.2: ADSB with QGC & Cube Orange - Sibu

Configuring ADSB in QGC isn’t working with CubeOrange (with Ardupilot it works).

Goal: Trying to receive the ADSB packets, and for pilot to have other vehicles on the QGC screen.

The tutorial followed (that didn’t work) is here:


Answer: There’s a separate PX4 (ADSB receiver onboard the drone) vs QGC (ADSB setting) usage.

Answer: Maybe you need to configure the MAVLink forwarding of the ADSB message to the ground station. It’s probably default parameter configuration issue.

Action Item: Sibu will open an issue “ADSB not working on Cube Orange” here: Issues · PX4/PX4-Autopilot · GitHub

D.3: Docker containers

This might fit in more with QGC, but is there any desire for QGC to be able to file LAANC requests?

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