A couple of queries.. hope someone can help :)
Im not sure if my IMU is faulty, but sometimes when I power up/reset the IMU board, the orientation that is obtained is SOMETIMES reversed.
(ie. in APM Flight Data window, the nose of the plane is pointing towards the back of the ACTUAL physical aircraft.)
Only upon resetting a few more times does it get the orientation right.
Has anyone encountered similar problems? How does APM obtain its heading direction anyway without a magnetometer?
Also....
APM obtains altitude readings from the baro pressure sensor. From the CLI tests, the fluctuation of the altitude can be as high as +5/-5 metres without wind... and up to plus minus 8-9metres in the presence of wind. If thats the case, how does APM get an accurate altitude reading? Am i supposed to shield the pressure sensor so that it is unaffected by the wind?
Thanks in advance!
Replies
Without a magnetometer it can only get heading from the GPS and only when it is in forward motion. Basically, if you're stationary the heading reading is random if you're not using a magnetometer.
If your APM board is exposed to the wind, you should cover it as shown in the manual here (bottom of the page).