Losing altitude when stopping forward flight

[racezilla]

I’m new to DJI and I noticed today that the Mavic lost altitude when stopping forward flight. Height of about 8ft and upon letting off the forward stick it would stop then lower itself several feet almost like it was going to land.
I’m uneducated on if there is a mode that does this intentionally. Or if there is a calibration issue?

 

[SkyeHigh]

It’s hard to say without more information.

At low height the internal barometer would not be accurate enough to maintain the height at which you stopped and would be using the downward facing infrared sensors to detect height by bouncing the light off the ground’s surface. How accurately it does this can depend a lot on what the surface is made from and how reflective it is.

The height information from the sensor is fed to the flight controller, which is then used to maintain height by controlling motor speed, while combined with GPS data and motion detection (3-axis) by the Inertial Measurement Unit. The IMU by itself cannot detect height above ground and GPS altitude data is nowhere near accurate enough to maintain static height.

So the cause could be varied. There is no need in this case to calibrate the IMU or Compass.

Does the height drop repeatedly?

Does it do the same at higher levels such as at 10, 20, 30, 40 meters?

What type of surface is the aircraft above when this occurs?

Is the issue the same regardless of the surface type?

 

[Meta4]

I’m new to DJI and I noticed today that the Mavic lost altitude when stopping forward flight. Height of about 8ft and upon letting off the forward stick it would stop then lower itself several feet almost like it was going to land.
I’m uneducated on if there is a mode that does this intentionally. Or if there is a calibration issue?

When stopping, the drone should tilt back a little (a lot for the Mavic 3) to brake and should maintain altitude.
There's nothing you can adjust or calibrate that would affect the issue you describe.
I'd do a little testing to see if it's consistently descending or if it was a one-off thing.

 

[racezilla]

Thank you both for taking the time to respond.
I’ll do some testing today and try to answer those questions.

It was over low cut grass in my back yard and in a shaded area. It was also facing a tree with approaching limbs and leaves so I didn’t try a higher altitude. My nerves got to me haha. It did not go into avoidance alarm or anything like that.

I shut everything down and restarted it and it didn’t do it again, but I only flew for a couple minutes after that.
So it was repeatable at first 7 or 8 times then after reboot it didn’t do it for 4 or 5 attempt in the same area at the same height.

I’ll check back in later today with updates. Thanks again for the suggestions.

 

[racezilla]

Ok so it seems to be fairly repeatable at low altitude. At 10ft or higher I don’t notice the slow decline. I was not able to move to a different location yet so it was still over short grass. However, it doesn’t appear to happen flying backwards at the same altitude. Only forward.

 

[lookout]

Usually it drops when you push forward. It might be something out of rig.

 

[SkyeHigh]

It would be good to know what happens at 30-metres or above where the infrared sensors are not in use. That may rule out or point towards these sensors being the issue.

 

[lookout]

I've flown over grass before. Quad makes for a tornado in my backyard. Recently though it's been acting like the visual sensors aren't working right.