Abstract: Embodiments of the present invention provide an approach in the time domain, instead of the frequency domain, for analyzing and correcting for radial propagation instability in servo-writing. In one embodiment, a system for controlling a read/write head of a disk drive to correct propagation errors during self-servo writing on a disk comprises a time-domain based controller to provide closed-loop feedback control to an actuator for moving the read/write head, the controller including a state observer. The controller is configured to measure read head position information of the read/write head on the disk; provide the measured read head position information to the state observer which produces feedback variables for feedback control of the read/write head, the feedback variables being weighted by feedback gains which have been determined a prior; and apply the weighted feedback variables to provide the closed-loop feedback control to the actuator for moving the read/write head.