Method and apparatus for calibrating read-head off-track detector

A method of operating a data storage device having a storage medium, wherein data is written to tracks on the storage medium, data for each track including a preamble, and wherein the preamble in any current track is orthogonal to the preamble in any track adjacent to the current track, and wherein data accumulated in a multi-dimensional space is representative of a relationship between signals from the current track and signals from at least one adjacent track, the method comprising:

• calibrating, in control circuitry of the data storage device, the relationship between the signals from the current track and the signals from the at least one adjacent track by, for each respective position out of a plurality of positions in the multi-dimensional space:
• accumulating, in the control circuitry, a plurality of data values for the respective position;
• and
• determining in the control circuitry, from the plurality of data values for the respective position, an inverted covariance matrix without performing a matrix inversion operation.