Dual range finder for altitude estimation


I’m currently using a LightWare LW20 on my drone platform running ArduCopter 4.1. Most of the time the sensor works well above water surface, but sometimes there is a hole in the data stream.
I also own a Maxbotix MB1240 sonar sensor that I would like to use in case of failure of the first rangefinder.

I would like to have a simple explanation of how the EK3 works when two range finders are configured in parallel, both looking down. Is there a data fusion happening? Is there a configuration of the EK3 affinity parameters for the rangefinders?

Kind regards.

No rangefinder data fusion is currently supported (but pull-requests are welcome :wink: )
No EKF3 affinity parameters AFAIK.

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Thank you for these clarifications. I still have a few questions.

What would happen then if both of my range finders are running at the same time? Is the second range finder able to fill the lack of data from the first one? which one will be used by default?

Thank you for your efforts, I really appreciate the help of this community.


me too, I’m currently using a LightWare LW20 and TFMini-plus running ArduCopter 4.1.
Code in /libraries/AP_NavEKF3/AP_NavEKF3_Measurements.cpp
// use data from two range finders if available

if use two range finders
EK3 seems to select data with a longer distance? But I am not so sure.

Best Regards,