Cannot Arm in any GPS mode: 16 sats, .7 HDOP 3D Fix = Error: No 3D Fix

ArduCopter Copter 4.0
22

Do tell us how that turns out for you.

Please post here, three months from now, how does PX4 compares to ArduPilot. Thanks.

1 Like
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I have never used PX4 but I have been using arducopter for many years now. Have not had so many problems and ā€œknown bugsā€ until this year. Itā€™s just not working for me anymore. I will let you know. Final straw was my copter resetting all itā€™s parameters to default after a week of troubleshooting.

24

If youā€™ve got a very new flight controller (like Cube Orange) you need to do the bootloader update and be on latest stable to avoid the param reset/memory issue.
Iā€™ve never had your exact GPS issues, althrough some days are different to others, depending on North Korean missile threats. The FENCE_ENABLE param is the only one you need to change.
In fact the best option is to leave the fence enabled and this forces the wait for good 3D fix. The only reason for you NOT to be able to arm (set home) is poor GPS position/acuracy and speed.
As far as Iā€™ve noticed there was no major changes in AC v4 that affect this stuff.
Iā€™ll try checking you logs

25

I did the bootloader update to ā€œfixā€ the cube orange problem last year. Recently on the Cube forums they said it is still a known bug and fixed in 4.1.0 beta. Not good enough.

How do I get a better fix than 17 sats and .7 hdop with an RTK station??? Iā€™m all ears!!!

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Discussion on Cube forums regarding parameter reset bug that still exists: https://discuss.cubepilot.org/t/loosing-parameters-on-cube-orange/4438/30

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In the log I looked at the horizontal and vertical accuracy arenā€™t ideal, and HDOP and VDOP actually got worse by a little bit over time - but they werenā€™t all that bad.

Iā€™d be interested to see how it goes with
GPS_GNSS_MODE,65
to limit the number of constellations in use. I find I get a faster more accurate fix when ignoring Beidou. I note that the manual says it should be ignored by default, but Iā€™ve found otherwise, especially with recent firmware updates that try to use all available constellations.

Have you checked in this doco and used the UBLOX and MissionPlanner RTK tools to see whatā€™s really going on? The Here v2 might not be your exact unit, but that doco is useful.
https://docs.cubepilot.org/user-guides/here+/here+v2-user-manual