MavLink UDP connections

I've written some C# software to listen to the RS-232 telemetry feed from the Taranis RC transmitter, sent by Frsky SmartPort sensors, and decode it on the PC.  For each telemetry value, like battery voltage, GPS location, etc., I update a ViewModel that can be bound to any UI on Windows that supports the INotifyPropertyChanged interface (Winforms, WPF, Windows Store apps). That GitHub project is here:

Now, I want to take that decoded telemetry and produce MavLink packets to send to Mission Planner and QGroundControl via UDP on port 14550.  Every second, I produce a Heartbeat and System Status packet and send that to the Mission Planner UDP port.   On Mission Planner, I select UDP and Port 14550, but nothing ever happens. 

The log says the VerifyConnected() generates a System.Exception: The socket/serialproxy is closed.  I'm not running Mission Planner in a debugger, I'm using the downloaded release edition from the website.

Any immediate insight here?  Next, I'm going to try this with QGroundControl, and then try Mission Planner again, hopefully in the debugger, but I thought I'd ask here first.

Thanks in advance,


Seattle, WA  USA

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  • Too late for a reply... but just to record I believe the solution is described here


    You should be listening form messages on port 14550 on your computer. When you get a UDP packet, inspect it to see where it came from (should be and which port. Then send your message to that 'return port', the port wiil not be 14550.

  • Ok, so after a little tweaking of the socket code, I can connect to both QGroundControl and Mission Planner, although the Mission Planner connection eventually times out on getting params.  But, Mavlink does work.

    Now, it's a matter of sending the correct Mavlink packets when the telemetry is updated.  I should have this working shortly.

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Dec 3, 2020