Hi, we’ve come across a bug which results in a number of issues with the altitude limit in the Geofence. In summary, an altitude breach violation can trigger unexpectedly, causing the drone to ascend to an inappropriate set-point. This breach violation will continuously trigger, causing the drone t…

Further inspection of the PX4 firmware shows that the vertical braking distance is calculated incorrectly. Whilst the drone is stationary, the braking distance is output as ~5m. This is what’s leading to both the Geofence being triggered prematurely (as it influences the prediction as to whether or…

Hi there, any updates on that issue? Please post that issue also at Issues · PX4/PX4-Autopilot · GitHub to get more attention. I had the same behaviour leading to a premature activation of the geofence.

I will post a link to this in Geofence issues · Issue #16679 · PX4/PX4-Autopilot · GitHub

Hey sorry I completely missed your reply, yes we went and modified the behaviour ourselves so that the geofence is triggered based on the UAV’s current position, not its predicted position (current position + calculated braking distance). This leads to the UAV still overshooting slightly past the g…

Hi, I realise this is a bit stale now, but I think I have a fairly comprehensive understanding of the issue and I’m happy to discuss it in more detail if it helps any of the dev team implement an official fix. We’ve implemented our own workaround in the meantime though so should be okay for us for …

Woudl you be able to join this weeks dev call on at UTC? I would be happy to bring this up so that we can discuss this. Or, maybe if you are inclined so, you can create a PR?

I’d be more than happy to depending on when it is, what time and date would it be? Sorry, tried to reply by email a couple days ago without realising it was from a noreply account.

FYI, it seems like the “Position * interval” math error you mentioned doesn’t exist in the codebase: PX4/PX4-Autopilot/blob/main/src/modules/navigator/GeofenceBreachAvoidance/geofence_breach_avoidance.cpp#L218-L232 float GeofenceBreachAvoidance::computeBrakingDistan…

Yeah I realised that wasn’t actually an issue but just never updated this post again! Glad you spotted it as well. I won’t be able to make this week’s dev call as we’ve got quite a lot on at the moment, but would be happy to bring this up when I’m next able to join if that still helps (although fee…

Geofence Altitude Premature Trigger and Overshoot Loop

PX4 Autopilot

junwoo0914 August 9, 2022, 5:33pm 9

Oh no, sorry! Forgot to put date and time. It will be on August 10th, 3pm UTC. The schedule is here: Weekly Community Q&A Call (Previously "Dev Call") | PX4 Guide (main)

This will be our meeting note:

Topic		Replies	Views
PX4 Sync / Q&A: Feb 26, 2025 PX4 Autopilot	6	207	February 26, 2025
PX4 Community Q&A: April 05, 2023 PX4 Autopilot	8	1923	April 6, 2023
Wiki errors for EK2_GPS_CHECK PX4 Autopilot	9	181	June 15, 2025
PX4 Dev Call: August 10, 2022 PX4 Autopilot	1	729	August 10, 2022
PX4 Sync / Q&A: Oct 02, 2024 PX4 Autopilot	0	110	September 29, 2024

Geofence Altitude Premature Trigger and Overshoot Loop

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