Altimeter radar behavior is too aggressive when you fly over trees

Radar behavior is too aggressive when you fly over trees
We have also tried the lidar and it has the same problem.

I had hoped that the radar would fix it because somewhere it says that it penetrates the vegetation, but not at all.

The issue is that you need some kind of filtering. At least be able to modify the speed of ascent and descent. But the parameters WPNAV_SPEED_UP WPNAV_SPEED_DN don’t work for this because it seems that when you use the radar you only use the height that comes from the radar.

Someone have the same problem? any solution?

You have configured it wrong. Please describe what behavior you want to achieve and publish the full parameter list of your copter

I agree, this is the biggest problem with Arducopter‘s rangefinder terrain following. Some kind of algorithm that averages the measured height during a short distance would be nice.

Or, maybe it could be a approach, if there would be a posibility to adjust the climb/decent speed during terrain following (independend of WP_NAV_SPEED)

So is RNGFND_GAIN ineffective for your use case?

Thank you for the hint. I tried different values with this parameter in the past. But it was a litte bit mysterious to me. Are here any units, or any further explanations?

Did you read the entire documentation about terrain following?

again, please post your parameters

@amilcarlucas Yes, of course I read the documentation quite well, I think. And these are my parameters, for example:

I’m using terrain following with rangefinders under very different circumstances for a while now. For example, we are flying above whine yards with terrain differences of more than 80m within a distance of 200m. I know the documentation quite well, I think. But I never find a real explanation of RNGFND_GAIN.

It is a fact that the rangefinder based terrain following ist quite aggressive. I’m not the only user who would like to have the possibility to “soften” the terrain jumps a litte bit. Maybe RNGFND_GAIN is the right hint, but I do not understand the exact function of this parameter and its values.

radar model do you have ?
How did you configured it?
What driver did you used on ArduPilot?

it is a nanoradar NRA24, it has a special firmware and emulates the “ulanding”. it seems to work great.
We have done some quick tests with RNGFND_GAIN and it seems to smooth the behavior. Our drone is big and it’s scarier than a small one when it sinks. I think RNGFND_GAIN will work if we become familiar with it and adjust it for each scenario.
Still testing!

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Does RNGFND_GAIN also work in Auto mode?

Normally no, do you have found a solution for reduce aggressive , I have a same problem.

I tried to sum up the issues regarding terrain following with rangefinder here: Rangefinders for Terrain Following in Auto Mode - Usability, Questions and Issues

Maybe you can follow up.

RNGFND_GAIN seems to smooth the radar behavior, it seems an gain of a integrator control.
it works in all modes.

You need to setup WPNAV_RFND_USE=1 and TERRAIN_ENABLE=0 to use range finder in auto modes.

Regarding to @rmackay9 in Problem of rangefinder in Auto mode , RNGFND_GAIN has no effect in Auto mode.

Do you have resolve your problem of agressivity with the lidar ?