Mocap Issue with Taranis Transmitter and WiFi

Hi there,

This is not entirely specific to the PX4, but it might be worth mentioning in the documentation as it is an issue with the recommended hardware. The Taranis X9D and X7 have a very wide and strong emission at 2.4GHz. They tend to cause issues with nearby wifi routers. The result is a random high ping (2000ms+) from the mocap system to the companion computer (Raspberry Pi). This can and has caused crashes.

Therefore, I would strongly recommend using a joystick for all indoor control. We will be updating the documentation of our mocap system to suggest a PS4 controller, it works great. I suggest to update the PX4 offboard page but I might be a good idea to obtain independant confirmation. In addition to my own tests, I already have a confirmation of this problem from two clients.

@charles-blouin Is this using the onboard WiFi on the raspberry pi? (which raspberry pi are you using?).

I had a external wifi module and this was not a issue for me. Moreover, using 5.8GHz might help

This is using the onboard wifi on the Raspberry Pi 3 b. This issue does not happen all the time, it seems to be dependant on the room geometry and material. We had been flying for many months using the Taranis in our lab, but some people had weird issues much more consistently. I was able to confirm that the issue is repeatable: the ping increases significantly with the Taranis controller on. However, the disturbance is sometimes not enough to cause noticeable issues. Given how critical the wifi link is, I think it is better to not take chances, but you are right that an external wifi dongle should help.