GPS signal lost or Radio signal lost??!!

Hi everybody,

this is my first post in this beautiful forum and looking forward to be an active member.

I had a problem with my APM the other day which I  can summarize as follows.

-Took-off on manual mode

-switched to Auto and everything was smooth as usual for a 5KM route and with fatshark goggles on.

on the way back the plane started circling and maintaining altitude, yet it was drifting with wind direction.

-I turned off my controller and restarted it -discovered later that the battery was low- and after a few trials i got it into RTL.

I had my short and long fail safe set, so it should've came back after 20 second where as it circled for around 1.5 minutes.

my question is that, could it be a GPS signal loss ? and is there anything i can do to avoid this?

I checked the log file and it showed a fail safe at 900ms PWM input which indicates a radio signal loss but I couldn't find any indication of a GPS signal loss in the log, I'm not sure how the GPS signal loss is logged in the log file, so what do you guys think?

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Replies

  • Hi guys,

    thanks for the reply. i've listed down the time spent in each mode, you can see that it kept circling for 137.6 seconds that's what worries me, why it didn't go into RTL after 20 sec knowing that I have the long FS set.

    the other modes changes could be justified, it went into RTL when I told it to do so using my controller -lifted it up in the sky :) .

    any ideas guys?

    auto 703.6
    circle 137.6
    man 29.6
    circle 2.2
    man 6.8
    circle 4.4
    man 7.6
    circle 9.8
    man 8.8
    rtl
  • Developer

    It goes into the circle, so as to not rely on GPS for position. This is deemed a better failsafe. If GPS is ok at 20s it will enter RTL. In your case your receiver was regaining connection so not going into long failsafe. Having an RTL switch programmed on the TX, or just keeping it off would have helped.

  • Hi, the circling without a fixed center is normal short failsafe. All the controller does is to maintain a constant bank angle. The reason for not trying to maintain a fixed center, I have forgotten. But it was not silly :)
    Probably the RC signal has been on/off at the plane every few seconds so there were never 20 seconds without signal, so no long failsafe action. You can reduce the 20 seconds I think. You can also set the failsafe value for ch8 in the receiver to your value for RTL. This _should_ really be ignored while throttle failsafe is active, but is it actually? Some ppl turn off throttle failsafe and set the receiver ch8 failsafe value to their AUTO so the (well planned) auto flight continues....
    Regards, Soren
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