Raploc
lvl.3
Flight distance : 22598 ft
Netherlands
Offline
|
Griffith Posted at 2017-12-26 13:04
OR... the other possibility is that there was a change in atmospheric pressure during your flight. Even a change as small as 0.01 psi can result in almost 20 ft change in calculated altitude. In any case your takeoff altitude is always 0. I don't think the IMU does any recalibration during a flight, but probably only reports a moving average of the last few data points. If your pressure sensor is flaky it may produce an erroneous average, but I don't think, in that case, you're readings would be as consistent. My vote is pressure change. Butas Hallmark commented, VPS is much more accurate when within range and over a relatively solid surface and is insensitive to atmospheric pressure (mostly :-) )
I think you are right, a drop of 1 hPa would be about 8 meters (24 ft). That would explain the difference in height. Too bad the spark doesn't calibrate the barometer with the vps system during the flight and that it is used as the height reference in the app during playback. |
|