There are a couple of factors affecting this.
Although DJI label one of the altitude fields in the metadata GPS Altitude, for most DJI drones, the number does not come from GPS.
Instead it comes from a completely unreliable conversion from air pressure that uses invalid assumptions.
And if the
Mini 2 is actually using GPS data, the reason that could be inaccurate is that GPS does not know where sea level really is because it uses a mathematical approximation that does not properly account for the irregular shape of the earth.
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