Maintaining same altitude over sloping ground

I’ve got a Mini1, and I want a shot of it going as fast as possible, fairly close to the ground.
2 Qs:

  1. If the ground is gently sloping up, will it rise to compensate, even in sport mode? Obviously it won’t handle a sudden rise.

  2. If the ground is sloping down, can I just keep some pressure on the down altitude stick and have it keep at minimum flight altitude at full speed forwards? I’m assuming it won’t suddenly try and land.

Has anyone got any experience with these scenarios?

Here’s a video of the sort of thing I want, but lower.

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  1. No it won’t rise with the land as it has no downward obstacle avoidance. It will just crash into the ground. But that wouldn’t work how you want even if it had it.

  2. You can keep a slight pressure on the down stick but it’s some thing you would havecto keep an eyevon as too much it will crash into the ground, too little and the gap between the drone and the ground will get greater.

Basically you will just need to practice, getting faster as you get better. It’s probably ( I’m no expert as I don’t do it yet) the very basic of fpv maneuvers i.e. learn to fly fast , straight and level. Then the same with a slight increase or decrease in altitude.

I’ve practiced stuff like this on the beach.

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Hmm, it definitely does have downward sensors, as it stops descending at about 1m if you’re manually landing it, and if you try an descend below that it just goes into landing mode. And I’m sure if I move my hand under it, it increases altitude.

Weren’t there some reports of them crashing over water when the reflection confused the downward sensors?

It does

Off by default in sport


Just practice then!
What about the 3 Pro? (which I am very likely to upgrade to soon)

Even more sensors, but all switchable

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You’re right of course , but they pretty much don’t work as obstacle avoidance more a check to see if there is something solid to land on and then turn the motors off, in fast forward flight even in normal mode, due to the angle of travel of the drone, it’s more forward sensors which would stop you crashing into the ground in this scenario.

The downward sensors are not so much to stop you crashing down but to make sure there is something for it to land on. If you watch a drone with forward obstacle avoidance as it approaches a wall it will stop, it doesn’t matter how long you push forward for it still won’t go forward, unlike the downward sensors keep pulling down it will move down and land.

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Same, as i just wrote about how the sensors work you would have to turn them off if you want to go really low.

Great, thanks for the info.
I might try a slow one just to see what happens with ground that gently slopes upwards.

you could achieve the “fast” by filming slow and then increasing the playback speed in post, as long as you don’t have any moving objects in the footage that will give the game away e.g. Benny Hill walking

You could use Litchi for this, and set your desired altitude above ground and speed within the mission before hand.


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Will Litchi work with height above ground with the Mini 1?

I’ve decided for definite that I’m going to upgrade to the Mini 3.

Yes, that is what Litchi does. Using the mission, it ensures that your specified altitude is maintained above the ground whilst flying at the speed you set throughout the entire mission. I believe it does by using Google Earth elevation data for your planned mission. It then adds your desired altitude to this to ensure it flies at a fixed height above the ground at all times.

I used this approach when searching for my downed Mini 2, many kms, in a grid formation over sloping fields.

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How accurately will it do this, let’s say you are 1 meter above the ground.

is google earth elevation data accurate and what about the drone barometer accuracy


Dunno. I’ve never used litchi to fly at max speed 1m off the ground :man_shrugging: Personally, I don’t think you would need to go as low as 1m to achieve the desired effect, 3m would be low enough at max speed.

This is how it looks, using Epsom Downs Racecourse, 3m altitude at max speed. See the red line - this is the set altitude of the Mini.


Litchi on Mini 1 sucks ;o(

Its joystick commands only, so once range gets iffy (which it does on the original Mini) back it comes.

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Even if you set it to ‘complete the mission on disconnect’ in Litchi?

Yeah the latest drones use virtual sticks so if you get a disconnect the RTH kicks in

Only on the older drones will complete the mission work


Given that sensors, Litchi, on board barometer and VPS all have tolerances and given that Google Earth height data is probably not sampled very 25 cm or so along and across a surface the likelihood of various factors combining to give a resultant negative height above ground on a fast minimum altitude run is fairly high.

Stevesb’s answer, practice doing it manually and slowly, building up speed as it become more familiar is, IMHO, the sensible way to do it.


Just get into FPV :ok_hand:t2: lol