UWB Based Positioning System

ArduCopter
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Dear all,
I’m working on an UWB based indoor positioning system. I’m using an ESP32 UWB based dev board (ESP32 UWB(Ultra Wideband) | Makerfabs) and plan to attach one to the copter (tag) and the others as static anchors with known position. I’m doing this for the first time and I have some conceptual questions:

  • From each anchor I receive the tof measurement and hence the relative distance
  • Since I know the static position of the anchors, I can use triangulation to obtain an position estimate, which I could compute on the tag and send to the FCU via Mavlink (and e.g. mimic a Vicon indoor positioning system, since it should be already integrated in the EKF2/3)

That would be the simplest approach in my opinion. I assume better were if I could integrate the measurement in the EKF itself. I also could show via Simulink and Python that this works, but that would mean I need to operate at the heart of Ardupilot and I wont feel confident enough for this atm.

I thought as approach between those two, I could run a separate EKF on the tag (the ESP32 has enough computational power for this) with a constant velocity model and the UWB measurements as observation + Mavlink input from FCU with velocities. Despite the computational effort, I believe this would also enable the integration of more sensors without meddling with the Ardupilot code base. The estimate would, like in the simplest approach, send as indoor positioning message via Mavlink back to the FCU.

Can you advice any of those directions? Any thoughts would be much welcomed :). Thank you!

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The Beacon system is already integrated into the EKF. That is already doing the trilateration and location estimation

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Instead of Vicon it’s probably easier to simulate a PoZYX system, which also operates on UWB.
Unfortunately the PoZYX system is quite large (not suitable for 3" copters and below), so if you manage to make it smaller it would be a noticeable improvement

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4

Your are correct. I also looked into it. Maybe I need to be more specific on my use case. My use case is indoor inspection and the beacons/anchors can also be mobile. My understanding of the Beacon system is that these need to be fixed position. I’m able to track the motion of my anchors and can also send it to the tag. Hence the idea of a separate EKF running on the tag. Or would this still be possible with the Beacon system?

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Thanks for that hint, I was already quite focused on Vicon, but will gibe that a look, too.

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you could probably do it without extra hardware using esp32.

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