Hello
I've noticed that when vision system is not reading height from the ground, the height consistently reads negative. My picture below is what I took of my Mavic idling in place on the floor in my house. The reading slowly works its way down to negative 2 - negative 4 feet without moving, just idling in place. If I'm outside and I go fly around, when I return to eye level height, the distance reading is again usually negative. Sometimes reading negative 20 feet. I always do a compass calibration before the flight, though I don't think that should matter in this instance. Any ideas why I am constantly reading a negative height? Anything I can do to fix this? It seems specific to the barometric reading since DVS usually is able to properly identify the height.



Thanks

Hello Wind Junkie, please try to do the IMU calibration on a complete flat surface.
Let me know if this helps.

Hey Mindy I'll try and update once I re calibrate. Thank you

When you activate the props, do you leave  the Mavik on the ground (floor) for a while,  or ascend a few feet?  

I don't have any knowledge of the barometric sensor location or when, in the initiation process, the reference pressure is taken - immediately upon power-on, immediately upon prop activation, or a few seconds later.  However, I can conceive of a situation where the drone, on a flat surface with props whirling, could create a higher pressure zone around the lower body of the drone during the baseline pressure reference measurement, thus leading to a negative (relative) pressure reading while hovering.

Just thinking out loud :-)  Maybe the DJI software folks could shed some light on the initiation process.

Try ascending a few feet immediately upon prop activation.

Griffith Posted at 2017-1-19 08:14
When you activate the props, do you leave  the Mavik on the ground (floor) for a while,  or ascend a few feet?  

I don't have any knowledge of the barometric sensor location or when, in the initiation process, the reference pressure is taken - immediately upon power-on, immediately upon prop activation, or a few seconds later.  However, I can conceive of a situation where the drone, on a flat surface with props whirling, could create a higher pressure zone around the lower body of the drone during the baseline pressure reference measurement, thus leading to a negative (relative) pressure reading while hovering.

Good post even though I have not experienced this, I would love to know what the resolution is for this problem.