Using GuidedMode without GPS - sending velocity commands

ArduCopter
1

Hello together,

We need to send velocity commands via MAVLINK like in GUIDED mode, but without requiring a GPS Module on the copter itself. As we need the velocity commands, GuidedMode_NoGPS is not an option for us as it only accepts attitude targets.
Is they any work going into this already?
We have an OptiTrack system in our Lab which we could use to gather the copter position.

Greetings

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2

You could install a PX4FLOW sensor or pipe simulated GPS commands into the autopilot from your OptiTrack system. Then you could use GUIDED mode to control velocity.

The approach I took previously (with an OptiTrack system using Tracker) was to program our own position hold controller that ran external to the autopilot on a Raspberry Pi and leveraged STABILIZE mode and RC overrides. It works very well but required a bit of development time.

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3

Hi there,

thanks for the quick response. I think we should go towards simulating a GPS. Do you know if it is possible to send simulated GPS coordinates via MAVLINK (we have a companion computer onboard which could do that) or do we have to go the “hard” way directly to the GPS header using the NMEA protocol?

Greetings

4

I haven’t done it personally, but I’d seen some forum traffic about it and believe it can be done. This might be a good starting point.

https://discuss.ardupilot.org/t/feed-copter-gps-updates-from-companion-computer/14097

https://discuss.ardupilot.org/t/use-external-positioning-system-for-higher-accuracy/13666/10

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