Servers by jDrones

GPS Fail during Failsafe RTL


(Emiliano) #1

Good morning everyone.
I had a problem at the GPS during a flight near my home, I passed under high voltage cables and bumped a cable with the wing of my Bix3.
Right after my Frsky X7 started playing for low RSSI.
The APM went first in Failsafe Short (CIRCLE) [timeUS 818844522] and after 5 seconds in Failsafe Long (RTL) [timeUS 824018090].
Unfortunately the GPS went haywire and started to send the same position but the number of satellites drop to zero.
The plane started flying in the opposite direction to the home location for 5km until the end of the battery.
Luckily I had mount a GPS tracker and after an hour I managed to recover everything, with only some damage to the fuselage.
My question is, why if the satellite number was zero the APM did not put itself in CIRCLE?
This is a firmware bug or is a choice of software development.
The flight log is available HERE

Thank you all.


(peterbarker) #2

I had a problem at the GPS during a flight near my home, I passed under high voltage cables and bumped a cable with the wing of my Bix3.
Right after my Frsky X7 started playing for low RSSI.
The APM went first in Failsafe Short (CIRCLE) [timeUS 818844522] and after 5 seconds in Failsafe Long (RTL) [timeUS 824018090].
Unfortunately the GPS went haywire and started to send the same position but the number of satellites drop to zero.
The plane started flying in the opposite direction to the home location for 5km until the end of the battery.
Luckily I had mount a GPS tracker and after an hour I managed to recover everything, with only some damage to the fuselage.
My question is, why if the satellite number was zero the APM did not put itself in CIRCLE?
This is a firmware bug or is a choice of software development.
The flight log is available HERE

The vehicle probably went into dead-reckoning mode to attempt to complete
its RTL.

There’s enough information in the log to indicate that the EKF wouldn’t
have been happy giving a position estimate.

A more complete log might yield more information.


(Shawn) #3

Counting the youtube videos of drones that go near powerlines then fly off or crash is one of those tasks that can only be attempted by clustered supercomputers - just joking, but there are lots!
Powerlines, particularly higher load (supplying more premises) will have fairly significant magnetic fields. This WILL affect a flight controller unless you’ve taken steps to shield it somehow. I’ve seen where the powerlines appear to “suck in” the multi-rotor and soon afterwards the show is over and people leave with a lot more parts than what they came with.
The same would be true of any craft, fixed wing or heli, when using flight controllers with compasses and GPS etc.