Ok, the title of my post was designed to be provocative! It does not reflect my feelings about Ardupilot though. I have been using Ardupilot for years but only recently had the enormously frustrating experience of being reduced to total newbie befuddlement when needing to set up copter and compass with non standard alignment.
Between Mission Planner and Ardupilot firmware, the entire compass set up has the potential to drive you crazy. I so often come across postings where really experienced people just cannot get their compass set-up. This all seemed to really flare up when EKF was made mandatory. Now I get that EKF brings huge gains in flight stability and the work done to integrate this into Ardupilot is impressive, But the people leading Ardupilot should address the downsides of this. With EKF between you and a compass reading, if more than 2 variables are off you really are screwed and all you will see is red EKF compass errors. Two variables in my case were a buzzer too close to my internal mag and poor wiki section on explaining how FC and Compass orientation interact (so my compass orientation parameter was off).
I think we have come to an interesting place when a Storm32 gimbal can be set up and calibrated more easily then a Pixhawk. Why are we having to set IMU and Compass orientation manually anyway? If I am moving my vehicle nose up, nose down, left, and right, and on its back how hard would it be to to get the FC to know how to set that AHRS parameter?
And like wise, in the age of smartphone apps with compasses, why can we not have to option to point our vehicles north, south, east, and west and thus determine compass orientation?
The wiki does need more clarity on this as well. It sort of left off with a 3DR Pixhawk and GPS Compass with an arrow. Most of the best GPS mag hardware has no forward arrow, and it is easy to get the roll and pitch axis mixed up – I even have a mis-labelled CSG GPS/Mag and had to look at the spec sheet of the mag chip to unpick this. Among many advanced users, there seems not to be a clear understanding of the compass rotation relative to the flight controller rotation and UAV forward direction.
And finally, can we please enable raw heading info in Mission Planner BEFORE EKF filtering – even if it was only in the compass calibration page so we can at least see if our vehicle facing north was generating a sensible reading.
I hope this posting can spur a positive debate as to how we can make it easier to use and deploy Ardupilot in the era of non-standard hardware. I do feel like setting up a Pixhawk or its ilk can be a little like having to re-wire my kettle each time I want to make a cup of tea!