Methods and apparatus for ascertaining a position of a read/write head relative to a reference position on a rotatable disk in a computer disk drive are disclosed. In one aspect of the present invention, a method for determining the position of a read/write head relative to a reference position on a rotatable disk in a computer disk drive includes reading amplitudes of a set of servo bursts embedded in tracks of the disk and classifying the servo bursts into a converging servo burst set and a detection servo burst set around the reference position. The method also includes forming a position error signal by augmenting a detection servo burst signal with a converging servo burst signal as well as a normalization factor. The converging servo burst signal is formed from amplitudes of the converging servo burst set at the position of the read/write head. The detection servo burst signal is formed from amplitudes of the detection servo burst set at the position of the read/write head. The position error signal represents an offset from the reference position.