Can I use range finder and terrain following in Loiter mode?

As the title states, what is the effectiveness of a LightWare SF11c on my quad if I am mainly flying in Loiter mode? I do also intend to fly it via waypoints over mission planner, but I am mainly curious about the functionality of it currently in a manual flight mode. I can tell that it does follow terrain to some extent because I have tested it while flying a few feet off of the ground, and then flying towards a hill and watching it correct altitude on the front and back sides of the hill. My only concern is that at low altitudes (such as a few feet) it definitely doesn’t seem to respond optimally, and I am wondering if I can make it work a little better.

Also, I wondered if I can make it keep a relative height when I am flying along in manual mode and the drone suddenly sees a rise in the ground (such as flying over a building rooftop)
Can I make the drone keep it’s current height above ground even when the ground changes below it drastically? If I am flying at 50’ AGL and suddenly I go over a roof top, I want the drone to correct and elevate to 50’ above that “new” ground level… and then re correct and descend once that false floor is gone.
maybe it isn’t possible in a manual flight mode, and that’s what I need to know.

Thanks!

As far as i know you can only “follow” terrain during a mission if you have selected it in mission planner while creating it.

Corrado

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Thanks, that’s the consensus that I am also getting.

Im flying with a sf11 for a long time now, I commonly used pos hold to fly fpv, you need to use any hold altirude mode like pos hold, alt hold or loiter.

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Here some experiences https://diydrones.com/m/blogpost?id=705844%3ABlogPost%3A2283337

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We’ve got this new wiki page which describes terrain following in manual modes. The RNGFND_GAIN could be adjusted to see if it helps with terrain following.

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I am not sure i understand how to activate it.

Do i have to assign it to a switch? Once the switch is flipped it will terrain follow in loiter mode?

If the switch is off will it still follow terrain during a mission created with terrain follow option?

Corrado

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Corrado,

Assigning a switch is optional - having it allows the pilot to turn terrain following off in loiter.

The same switch will turn off the rangefinder’s use in terrain following missions … that will lead to a “terrain failsafe” (i.e. the mission requires terrain data but it’s not available) or it will fall back to the SRTM data (a small database on the flight controller that holds the terrain altitudes in the area).

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So if i have understood it correctly as long as i have a rangefinder installed and working it will follow terrain in loiter mode without the need to do anything, is this correct?

Corrado

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Corrado,

Yes, that’s right.

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@rmackay9 is there a parameter that I actually have to enable for terrain following in auto or waypoint mode? my quad seems to follow terrain in Loiter mode just fine, but it seems whenever I look at the param list, I will see selections that say “this is not for terrain following” so I am unsure what I need to actually activate for it to use the lidar and follow terrain in a WP flight.

@Iron_Donkey,

We’ve got another wiki page here which describes the setup for missions using terrain following. The key thing is just to set the altitude type to “Terrain” for the mission or individual waypoint.

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I am also trying to understand better the terrain following mechanism. I see that it either works with using the elevation data obtained from the GCS’s mapping source (SRTM) or using a rangefinder. Since rangefinder’s have a maximum distance that they provide accurate distance measurement to the ground or object below what happens above this height (RNGFND_MAX_CM) ?. Does it then use the barometer and SRTM data ?.