The rangefinder took over, or gave up, the height for landing
What ArduPilot says:
- Rangefinder engaged at N.Nm
- Rangefinder disengaged at N.Nm
During an automatic landing with RNGFND_LANDING on, Plane begins to take its height from the downward rangefinder once ten changing readings in a row are within its range: “Rangefinder engaged”, with the height measured. From then on the barometer's drift is corrected and the flare comes at the true height. “Rangefinder disengaged” means the correction moved more than 30 m from where it started: the rangefinder is taken to be faulty and the landing goes on by the barometer.
What to do, most likely first
“Disengaged”: the rangefinder gave readings that jump, over water, tall grass or at a steep bank.
FixLook at the rangefinder's distance in the log during the approach. A sensor that jumps by tens of metres needs a better mounting or a clean window before it is trusted for landing.
Parameters to look at
| Parameter | What it is |
|---|---|
RNGFND_LANDING | Enable use of rangefinder |
RNGFND1_TYPE | Rangefinder type |
RNGFND1_ORIENT | Rangefinder orientation |
The code that sends it
Rangefinder engaged at N.Nm
ArduPlane/altitude.cpp Plane::rangefinder_height_update() · Open in ArduPilot Plane-4.7.1
Rangefinder disengaged at N.Nm
ArduPlane/altitude.cpp Plane::rangefinder_height_update() · Open in ArduPilot Plane-4.7.1