Rangefinder as a primary altitude source

ArduCopter Copter 4.5
1

I want to use TF02-i as my primary source for altitude, I am getting the rangefinder data, but when I set EK3_SRC1_POSZ = 2, it is not taking the rangefinder measurements for altitude.

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@rmackay9 @rishabsingh3003 @amilcarlucas Need help.

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  1. Post a log file demonstrating the issue, it likely will require having LOG_DISARMED to 1
  2. Is your sensor in configured range?
  3. Using rangefinder as a primary altitude source isn’t recommend, use surface tracking as described in the documentation.
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It is not recommended. This is what explained to me. The explanation has a few more paragraphs, here is one of the paragraphs.

“if the ek3-srcx-posz = 2 (rangefinder) and the vehicle is not flying over flat ground the EKF’s altitude estimate will be bad. Every time the vehicle flies over something, the EKF will struggle for a bit to figure out what the correct altitude should be as it tries to make sense of the rangefinder data not matching the IMU.”

“Making both the position controller and EKF try to handle the position error leads to conflict.”

[Edit]
I have not done extensive tests, but I have tried the following configuration with a covered FCU (reduced vibrations and barometer drastically changes) and achieved good height control. Not sure about your requirements.

EK3_RNG_I_GATE,500
EK3_RNG_M_NSE,0.5
EK3_RNG_USE_HGT,63 # LW20/C
EK3_RNG_USE_SPD,6
SURFTRAK_MODE,0
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Hey, Thanks.
I am trying to work on a project where a drone tracks and follows another object and I want the altitude to be precise.
I’ll try the method you suggested. Just so that I understand clearly, If I cover the cube with some foam, I can expect better measurements. right?

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Not sure of the foam you are saying. We hope to reduce atmospheric pressure change due to exterior heat or vibration from propeller wash as much as possible.
If you cover it with foam, will it create vibration? if not, maybe can.

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What method did you use to reduce the transfer of vibrations to the FC? from the image I can see a canopy, it that it?

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We stick the FCU using 3M tape (1mm or 1.5mm thick) to the frame, covered by a 3D printed part. We ensure the frame we mount the FCU is stiff (rigid) that will not warp or flex when drone takeoff.