Hello all! I've been looking into this problem since my own woes with a 1.4 board and a moving, and drifting horizon that seems to adjust its own level while in flight. While my 1.4 board is having problems mostly related to what I believe is and IMU problem, there are a few things that can easily cause the same problems you report here. First, I've noticed that having low GPS signal can cause movement on the horizon as it tries to identify your location more accurately. Second is the airspeed sensor. This can cause HUGE changes in the horizon, and caused one of my planes to slammed into the ground. I'd recommend disabling it if you have one, and seeing what that does. Third might be an IMU problem. Try tilting the copter forward and to the left, holding it in that position for 10 seconds, and setting it back down, and see if that has any significant effects on the horizon. On my 1.4 board, doing so causes the horizon to think that it's at 10 degrees down and 10 degrees left after returning it to level. Luckily, I've found that HIL simulators work well with 1.4, and I now have a dedicated simulation rig :) If you would like to see if your copter's behavior follows my odd IMU problem, here is the link: http://diydrones.com/forum/topics/level-automatically-adjusting-in-...
Hope this helps!!
Hi there! :-)
Sorry for opening again the old one, but I couldn't find anything else regarding my issue..
I just came across a similar problem. My horizon is drifting slightly. While arming, I have a yellow flashing led (pre-arm error). I opened MP, and counted out every element, which is listed on prearm list. It turned out, that it has no gps lock (doing it indoors - normal), and INS are not calibrated (however this wasn't flashed on the HUD, and I have calibrated accel many times). I am not using any external compass (plane), Tried to calibrate inner compass (PX4), and it threw out compass 1 error: 99 (same for compass 2, and 3), but it started to collect samples, and in the end I got information, that calibration ended with success.
Trying to arm the plane - everything goes round again - it doesn't want to arm, yellow led, etc..
If I deselect GPS lock, and INS - it works. The led blinks blue (no gps lock), and PX arms, but what is wrong with the INS?
Did anyone have to deal with that kind of problem?