I've recently started to learn about altitude hold using barometer and acceleration values. I've found simple kalman filters codes, but I've read that extended kalman filter is more usefull and precise for this kind of use.
I've looked on google to findout differences between this two firmwares: APM Flight Stack and the native PX4 Flight Stack used with quadcopters. I've read that either use EKF filtering and some of PX4 libraries are getted from APM when compili