Took my M2P out today for its first flight and I noticed that when hovering at around 2m doing a few checks my height was showing at around 6m on the app.
I’ve have done all the calibrations i know of pre flight Inc firmware updates to both the drone and controller so im at a bit of a loss as to what this is, any ideas folks ?
At an altitude of 2m I would assume your M2P would be using its ultrasonic Range Finder. The readings can be influenced by air temperature, air density, air pressure, humidity etc.
If you want a guaranteed good night’s sleep (though I found it scintillating, but I’m just weird that way) there is a very good paper on range finding techniques for SUAV’s:
Regards
Nidge.
Did you calibrate the IMU?
Yes Alex I did this, may be worth doing it again?
There are 2 altitudes shown on Go4 app.
H - which is derived from barometric sensor and IMU
VPS - which is a readout from the IR tof sensor.
Which one were you looking at? The barometric readout H is not always reliable and can be influenced by weather changes and even wind.
That’s why it also has VPS altitude otherwise it would be a hard landing without accurate altitude
Thanks for this I will take a look. 
I pretty certain it was the barometric sensor/IMU but I will take a look closer next time I fly, thank you.
If that’s the case I wouldnt worry too much.
I’ve landed in the same spot as take off with a negative altitude showing a few times.