PreArm: fence requires position

Cube Autopilot
#1

Hello Fellow Cube Pilot Friends,

I was having an erroneous Battery FailSafe isue where the copter on a fully charged 3S battery would failsafe. I found that the powerbrick that we receive with CubePilot orange has to be set as other in Sensor Type in Battery Monitor. I also checked “Add suggested settings for 4.0 and up up in Initial Parameter” window. thei enabled GeoFence. As a result, I believe I started getting “PreArm: fence requires position”. Am I correct in my assumption? Once I set Fence_enabe to 0. The preflight error “PreArm: fence requires position” disappeared. Am I correct in doing so?

Thanks in advance

#2

Correct, you can disable the fence and you will be able to arm in any mode that doesnt require a GPS fix. The issue is there is no guarantee that home position will be set for RTL.
Starting in Loiter mode will force you to wait for a 3D fix and you won’t see the pre arm failure message, but it’s open to human error.
There’s no real downside to waiting for a 3D fix with the fence enabled unless you just fly acro.

#3

Hi Shawn,

Thanks for the prompt response.

I always want to fly with one GPS mode, such as RTL, so that in case of Failsafe, the copter RTLs to Home position. I do not fly Acro, as I am thinking of creating applications based on GPS.

So if I want the copter to RTL in case of a failsafe or just because I would like to use that mode, do I need to leave the Fence_Enable to 1. If so, what would I need to do get of the Fence_Enable error which is still showing. I have 3D GPS fix

Asim Khawaja

asimkhawaja@outlook.com

416-389-1551

From: Shawn via Cubepilot noreply@discuss.cubepilot.org
Sent: Wednesday, March 9, 2022 5:00 AM
To: asimkhawaja@outlook.com asimkhawaja@outlook.com
Subject: [Cubepilot] [Cube Autopilot] PreArm: fence requires position

xfacta Shawn
March 9

Correct, you can disable the fence and you will be able to arm in any mode that doesnt require a GPS fix. The issue is there is no guarantee that home position will be set for RTL.
Starting in Loiter mode will force you to wait for a 3D fix and you won’t see the pre arm failure message, but it’s open to human error.
There’s no real downside to waiting for a 3D fix with the fence enabled unless you just fly acro.

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#4

You can probably still see the pre-arm fail while the home position cant be reliably set, even though there appears to be a 3D Fix. You might be able to see your aircraft wandering around the map, or HDOP will be up near 1.0 (lower is better).
For the sort of activities you mention it would be best to set the fence and wait until the aircraft is happy.
A .bin log file will tell us more about what’s going on, you might be able to alter the GPS_GNSS_MODE parameter to get better/quicker results. In Australia I use 65.

#5

Hi Shawn,

Thanks so much for the guidance. With my 2 jobs, I have not had the time to try your suggestions. I will look into it as solan as I find the time. Once done, I will be looking into Object avoidance. Will keep posted