Copter: pre-arm check "Terrain data missing" when attempting to arm without GPS lock

[rmackay9]

[rmackay9]

It's possible that this is caused by the terrain failsafe and probably only appears if the vehicle is in Auto, Guided or RTL mode while disarmed.

[peterbarker]

You're suggesting this message should be squelched, I assume :-)

[rmackay9]

Yes, this warning is misleading I think. Saying that, I haven't seen it again myself nor has any user complained.

[IamPete1]

The cause is terrain failsafe, not related to arming directly.

https://github.com/ArduPilot/ardupilot/blob/25ee57080fb6f86487d67ad2c55f3b79e046ad67/ArduCopter/events.cpp#L270

I guess the correct fix would be to refuse to arm if were just going to instantly hit terrain failsafe.

[DanishVasdev]

Hi, I would like to work on this issue. Could you guide me on how would I reproduce this on SITL?...I am new to ardupilot so I am not sure exactly where would I find this I tried using the "testing GPS failure" given in - https://ardupilot.org/dev/docs/using-sitl-for-ardupilot-testing.html But here arming with this I couldn't see any such message on the console...only "pre arm fail" and "AP: Pre Arm: Bad Fix"

[Jai-GAY]

I got this message when testing a LUA Script. A day earlier, it was okay and I could repeatedly execute the script without any hardware or software reboot. It was the same 99% identical script, except for hover height change and number of times to execute the script. I cannot narrow down what could be the cause.

CubeOrange, 4.4.4.

GPS 1: specified as   UAVCAN1-125
Arming -> Taking off RC11 : 2
Taking off
Failsafe: Terrain data missing
Wait for arming : 2

# portion of LUA script, before that is in Loiter flight mode
    if vehicle:set_mode(copter_guided_mode_num) then -- Change to Guided mode
        stage = stage + 1
      end
      gcs:send_text(6, "Arming -> Taking off RC11 : " .. tostring(g_sw_pos))
    elseif stage == 1 then -- Stage1: Takeoff
      gcs:send_text(6, "Taking off")
      if vehicle:start_takeoff(takeoff_alt) then

[Jai-GAY]

get it again, same 4.4.4, same script, on different day.