Mini 2 altitude

[Chanc3]

I would like to ask for help in understanding how the mini 2 measures altitude. Lately I noticed that the altitude reading is off by at least 1 m as I am landing the drone, it shows -1.x even when i'm landing at the same spot/height as my take off point. My depth perception is not as good as I want it to be and I tend to fly low above water, so I rely a lot on the altitude displayed on the controller.

 

[teeroy]

I believe the elevation is measured by barometric pressure.

 

[DJayI]

I would like to ask for help in understanding how the mini 2 measures altitude. Lately I noticed that the altitude reading is off by at least 1 m as I am landing the drone, it shows -1.x even when i'm landing at the same spot/height as my take off point. My depth perception is not as good as I want it to be and I tend to fly low above water, so I rely a lot on the altitude displayed on the controller.

Some people discourage flying the Mini 2 low over water. I have no experience with it myself.

 

[SkyeHigh]

I would like to ask for help in understanding how the mini 2 measures altitude. Lately I noticed that the altitude reading is off by at least 1 m as I am landing the drone, it shows -1.x even when i'm landing at the same spot/height as my take off point. My depth perception is not as good as I want it to be and I tend to fly low above water, so I rely a lot on the altitude displayed on the controller.

To Quote DJI:

‘Vision positioning requires non-reflective, discernable surfaces, and adequate lighting. Available at altitudes from 0.5-30 m. The vertical and horizontal positioning accuracy is within ±0.1 m.’

The barometric pressure sensor gives height information but as implemented is only accurate to around 1-metre. Up to 30-metres the vision system provides far more accurate height above ground level (take-off point), above that height the barometric sensor is used.

It’s therefore not unusual for height variance before and after flight.

 

[Meta4]

My depth perception is not as good as I want it to be and I tend to fly low above water, so I rely a lot on the altitude displayed on the controller.

Don't rely on it to show an accurate height close above water or any other obstacle.
Your altitude displayed on the screen comes from a sensor that measures air pressure.
It's common and normal for that to vary by a couple of metres over the time of a flight, but that doesn't cause any problems.

 

[Chanc3]

Thanks for the responses, I was hoping it measures via gps.

 

[Cut.Aussie]

GPS is not very accurate for measuring altitude as it was never part of the original design purpose.
In real aviation GPS altitude use is not permitted as accuracy is assumed to be +/- 500ft.
For instance if I fly a gps approach using my Garmin, the glued slope turns off at approx 500ft AGL and tells me to make a visual approach.

The small altitude errors your seeing a simply caused by atmospheric pressure change over time.

 

[Chanc3]

GPS is not very accurate for measuring altitude as it was never part of the original design purpose.
In real aviation GPS altitude use is not permitted as accuracy is assumed to be +/- 500ft.
For instance if I fly a gps approach using my Garmin, the glued slope turns off at approx 500ft AGL and tells me to make a visual approach.

The small altitude errors your seeing a simply caused by atmospheric pressure change over time.

Understood, thanks.

 

[PaulDoneDrone]

I would like to ask for help in understanding how the mini 2 measures altitude. Lately I noticed that the altitude reading is off by at least 1 m as I am landing the drone, it shows -1.x even when i'm landing at the same spot/height as my take off point. My depth perception is not as good as I want it to be and I tend to fly low above water, so I rely a lot on the altitude displayed on the controller.

Logs are shwoing height is measured by both GPS and barometric sensor. I'm not sure what is beeing used to display the height in the app, maybe both.

 

[Meta4]

Logs are shwoing height is measured by both GPS and barometric sensor. I'm not sure what is beeing used to display the height in the app, maybe both.

The height you see on your screen is from the barometric sensor

 

[SkyeHigh]

Logs are shwoing height is measured by both GPS and barometric sensor. I'm not sure what is beeing used to display the height in the app, maybe both.

GPS height has an error of 10-20 metres under ideal satellite coverage. Ie. not accurate enough. The Earth is not a perfect sphere and has an irregular surface that has to be taken into account for any GPS-based height calculation.