Altitude accuracy

[mtsoule]

let me preface everything by saying that I am a newbee and have only flowen my P2V less than a week and about 7 times.

I have noticed that my altitude as reported by my iPhone 4 DJI app, says I am always higher than what I believe. for example, today, I was actuall at about 60ft and it reported about 100 ft. is this normal?

I believe that the P2V uses barometric pressure to determine altitude (read that somewhere, don't know for a fact), if that's the case I am sure it is not very accurate. what is a normal tolerance +/- 20ft?

also, I think the reported altitude is from home position, not sea level, is that correct?

thanks for the experience!

 

[Pull_Up]

The barometric sensor is inside the Naza flight controller, which sits on the middle of the main circuit board under the shell... right on top of a nice warm lipo battery! Air density decreases with temperature as well as altitude so that's probably got a lot to do with it, as well as ambient temperatures being higher in the summer anyway. And you're right, it simply takes the pressure at the moment of power up *** being effectively "zero" - so it's a measure of height, not altitude.

 

[ProfessorStein]

The barometric sensor is inside the Naza flight controller, which sits on the middle of the main circuit board under the shell... right on top of a nice warm lipo battery!

Never thought about that. Whoops!
Thanks Pull_Up.