Patent ID: 7595954

Claim:
A method of estimating repeatable runout (RRO) for a disk drive comprising: determining a plurality of position error signal (PES) values for a plurality of servo wedges of a track of a disk; and estimating repeatable runout (RRO) in the PES values for the servo wedges of the track by averaging determined PES values over a pre-determined number of revolutions of the disk of the disk drive and scaling the averaged PES values by a pre-determined ratio of the variance of non-repeatable runout (NRRO) to the variance of an optimal estimation of the RRO for the disk drive, wherein the RRO value is governed by an equation: R ⁢ R ^ ⁢ O = 1 n + r ⁢ ⁢ ∑ i = 1 n ⁢ ⁢ PES ⁢ ⁢ ( n ) ; wherein n is a number of revolutions of the disk of the disk drive, PES(n) is a summed PES value for the plurality of servo wedges of the track at an n-th revolution, and r is the pre-determined ratio of the variance of NRRO to the variance of the optimal estimation of the RRO for the disk drive.