Multiple rangefinders & how Ardupilot handles them during Terrain Following

Cube Autopilot
1

Hi

Currently we are using 2x NRA 24 radar range finders on a Cube orange for copter using copter 4.6.3.

Using multiple rangefinders for terrain following seems like the way to go for added safety.

However, it seems that the Cube uses the latest reported value from the available range finders during a terrain following mission.

This makes it very dangerous for sudden changes in terrain below the UAV.

When multiple range finders are available, the user should be able to determine how the latest healthy values from all sensors are used. In our case the minimum of the front and rear down facing NRA 24s can be used to increase the safety and accuracy of TF.

Is there something we can do about this? Or LUA scripts are the way to go?

Thanks

2

Have you set RNGFND1_POS_X Y Z parameters for both? This could have a noticeable affect for large copters. The values are in metres.

The data should be fairly continuous and out of range values would be ignored. The EKF merges all this data, and a tiny time difference between data points from one rangefinder to the other should be handled. The POS parameters compensate for the distance between sensors and also pitch and roll effects.

Providing a .bin log file could be helpful.