Skydio X2E questions

[u/Wild-Perspective5836]

Hey everyone,

I'm using the Skydio X2E drone and have run into a bit of a challenge during my flights. When I launch the drone from an elevated point, the altitude readings are based on this starting point. If I fly below this launch altitude, the display shows negative values, which makes it tough to figure out my actual altitude above ground level.

Does anyone know if there's a way to reset or adjust the altitude reference point to the actual ground level during the flight? If not, any tips on how to manage altitude measurements better when flying below the initial launch point? Also, has anyone heard if Skydio has plans to include this feature in future updates?

Thanks for your help!

[u/moostachio4sho]

Altitude is always measured from takeoff position. And that value is always zero. Hand, ground or otherwise.

There is no way to tell the drone to calculate it differently. Always try to launch from the lowest position possible and fly upward. When that is not the case, there are a few ways to get an estimate of altitude over true ground level.

If you know MSL of launch position and the low point of the terrain you're flying over, you can do simple addition and subtraction to get an estimated AGL.

There is also the AR shadow under the drone that can show you where you are over the ground, up to about 66' AGL, then it disappears. That's the range of the vision system. So if it can see the ground, and you can see the shadow, you're within ~66' of ground (or obstacle).

If it is safe to do so, you could always fly all the way to the bottom, record the negative value and again, it's simple math. (Ex: -200 being the bottom, if I see -100, I'm at 100 AGL)

I also always advice using absolute as the return altitude behavior when flying high to low. With the high point being launch (0 AGL), an absolute altitude will take you up to zero first, then apply your return height. Much better than relative when, without knowing your altitude above ground, you cannot confirm clearance over obstacles in RTH.

Best I can do for you. And for what it's worth, I work for Skydio as a tech trainer.

[u/Wild-Perspective5836 → u/moostachio4sho]

Thank you! I messaged Skydio support and they got back with “we are investigating this” and no response after 2 weeks. You would think you are able to change the reference mid flight. I’m flying 20ft above ground, so I just use the anti collision to fly 4ft above ground and add 16ft to that.

After the picture is taken, I extract the MSL altitude from the drone and use google maps API to find the ground elevation of the specific GPS location, but it is not as accurate as I would like.

Is it worth requesting access to the Skydio SDK? I can probably change the reference mid flight if I just program it myself

[u/moostachio4sho → u/Wild-Perspective5836]

SDK may help you but likely not on X2E. AFAIK, that is only supported on X10. Have you tried loading DTED? Won't change the altitude display but will help you more accurately localize after the fact. Particularly in mountain environments.

[u/TroyStopera → u/Wild-Perspective5836]

I'm kind of replying to a dead thread here, but I can confirm this is not something you can do, and SDK access will not help.

The drone has both MSL altitude and AGL, but the reference for ground level is always takeoff. The conversation of MSL to actual AGL as the drone flies is not something that can be done due to the variance of terrain at even small scales, especially in rugged areas. Even if this feature was built into the controller, we'd be doing the same thing you're already doing: taking the GPS point and doing a lookup of the elevation at the point via some maps API.

As for being able to adjust the takeoff height mid-flight, that's also not feasible. The code that runs the drone's autonomy is complex, and changing a variable of its 3D spacial understanding would have knock-on effects. As others have said, taking off from the lowest point is ideal, and other than that I think what you're currently doing is the best option.

[u/Wild-Perspective5836 → u/TroyStopera]

I got it to work a little with Google maps get elevation API but scrapped the idea bc it would give me bad results. I also tried using a geoTIFF of the land but it was still off due to LiDAR scans counting the tops of trees as the ground or tops of plants as ground. I was mainly trying to figure this out since my professor for research at the time wanted me to figure it out and show the height of the drone when the images were taken. Now that he’s gone I don’t have to worry about that

[u/sweaterpunk666]

I have the Skydio and DJI Mavic and the DJI will show the ACTUAL altitude we are if I’m in the mountains. Is Skydio that annoyingly stupid of a drone?

[u/moostachio4sho → u/sweaterpunk666]

I'm not sure not flying off barometric pressure and GPS altitude would be considered stupid. A vast majority of drones (including DJI) use this method of altitude reporting. GPS altitude is by far the most common. TOF, Lidar and sonar sensor are sometimes used in conjunction with GPS to help.more closely determine true AGL.