N7 Autopilot User Manual (ArduPilot) v1.0
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⚫ Need 3D Fix: the GPS does not have a 3D fix and the vehicle is in a flight mode
that requires the GPS and/or the cylindrical fence is enabled.
⚫ High GPS HDOP: the GPS’s HDOP value (a measure of the position accuracy)
is above 2.0 and the vehicle is in a flight mode that requires GPS and/or the
cylindrical fence is enabled. This may be resolved by simply waiting a few
minutes, moving to a location with a better view of the sky or checking sources
of GPS interference (i.e., FPV equipment) are moved further from the GPS.
Alternatively, the check can be relaxed by increasing the GPS_HDOP_GOOD
parameter to 2.2 or 2.5. Worst case the pilot may disable the fence and take-off
in a mode that does not require the GPS (i.e., Stabilize, AltHold) and switch into
Loiter after arming but this is not recommended.
⚫ INS not calibrated.
⚫ Accels not healthy: one of the accelerometers is reporting it is not healthy which
could be a hardware issue. This can also occur immediately after a firmware
update before the board has been restarted.
⚫ Accels inconsistent: the accelerometers are reporting accelerations which are
different by at least 1m/s/s. The accelerometers need to be re-calibrated or there
is a hardware issue.
⚫ Gyros not healthy: one of the gyroscopes is reporting it is unhealthy which is
likely a hardware issue. This can also occur immediately after a firmware update
before the board has been restarted.
⚫ Gyro cal failed: the gyro calibration failed to capture offsets. This is most often
caused by the vehicle being moved during the gyro calibration (when red and
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