Altitude Mismatch during Auto mission and RTL

ArduCopter
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1

2017-04-17.png1920×1080 139 KB

  1. When arming the Copter the DAlt and Alt fall bellow zero.
  2. Entire mission is of 5 meter altitude and the RTL Max Alt is also 5 meters but there is small change in altitude when RTL.
  3. When Landing back both the DAlt and Alt gose into deep -ve values?

Could Someone justify this log, Please…
Log is attached.46.BIN (998.6 KB)

2

The altitude dropping below zero on arming is probably ground effect. The baro is seeing a pressure increase, which it interprets as a lower altitude. On the ground, DAlt will follow that.

The increase in altitude upon RTL is is probably the RTL_CLIMB_MIN value. It will pop up that amount regardless of circumstance. I can’t say with 100% certainty that applies to the RTL command in a mission, but I would think it does and that’s what that graph looks like.

Upon landing, the same thing is happening to the altitude as it did when you took off.

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