Hi,
I am using APM 2.5 in a plane. Worked without problems till now. ALT_MIX is set to 1 for 100% barometer altitude. On the last flight missions the plane was always climbing away (flying much higher than it should).
I tried ALT_MIX = 0 which solves the problem, but this is no solution. Made a bench test by warming the APM with a heat gun. Watching 'press_abs' and 'press_temp' in the 'Status' window gives me about 5 units increase in 'press_abs' per 100 units in 'press_temp' , which translates to 5hPa (50m) per degree Celsius.
The APM is mounted in the fuselage (foam) without cooling, therefore a 4° temperature increase from the electronics makes the plane fly 200m higher.
Updating from 2.76 to 2.78b didn't change anything. Is there a parameter that I can change to fix that issue or do I have to buy a new board ?
Thank You
Replies
Good question, I'd like the answer as well. Sometimes I fly for an hour and the alt reading is out by a number of meters when I land. Perhaps we should use 0.7 or 0.8 to address the issue, or get this GPS, which seems to have a locked in altitude at all times:
http://www.virtualrobotix.it/index.php/en/shop/accessories/gps-ublo...