ive got the horizon droop. ive tried gimbal calibration which made it better but not straight. so I did a imu calibration in my lounge on the carpet, the floor may not be 100% level. do I need to get a piece of hardwood then level that?
Have you got a kitchen? The bench top should be pretty good.....ooh ooh just remembered ive got some granite slabs I sit my sub on with focule pods. I could level that up.
Here is a thread with some further links that might help understand how the level surface reasoning came up.Can anybody explain the reasoning behind the claim that an IMU calibration has to be done while the P3 is absolutely level? I've seen this so many times that it seems that people believe it because so many other people believe it. But, what is the technical reason?
It's often stated that the P3 won't fly straight if a slightly off level IMU calibration has been done. The reason being that in order to achieve straight flight in the X axis direction the P3 has to be perfectly horizontal in the Y axis direction. But, if the Y axis were held perfectly horizontal the P3 would wander and fly erratically. Besides not being perfectly level there other reasons the the P3 will wander, e.g. wind, gusts, or just ordinary randomness. In a sense the FC doesn't care what level is, it is trying to figure out what IMU sensor values it needs to see in order to achieve straight flight.
Are there other reasons that an IMU calibration has to be done on a perfectly level surface?
I think the main task of the IMU calibration is to make adjustments that minimize drift. I recently did an IMU calibration (on a close to level surface) where the before and after gyroZ drift was measured. There was 13 times reduction in the drift.
I looked into this. As I understand it the problem they were trying to fix is that when yawed about the Z axis the AC would move in a circle instead staying in one location. This could be fixed by doing an IMU calibration where the IMU module (not necessarily the AC itself) was perfectly level. Many people tried this and claimed that it worked; supporting the supposition that there is a real technical reason the fix works.Here is a thread with some further links that might help understand how the level surface reasoning came up.
Finally fixed my Yaw Drift
Test1. no Yawing, velH = 1.1.6 Meters/sec,
Yawing, velH = 1.08 Meters/sec
Test2. no yawing, velH = 1.09 Meters/sec,
Yawing, velH = 1.21 Meters/sec
NEW QUESTION:
Yesterday, I was up in the air and noticed a skewed horizon. I mean, it was way off for some reason. So I did a quick gimbal roll adjustment and thought "I'll do a full IMU and gimbal calibration when I get home".
Do you think it would be a good practice to zero out the gimbal roll adjustment before doing a fresh IMU calibration?
Chris
Wow, that's pretty severe.