Current methods of order tracking, such as synchronous resampling, Gabor filtering, and Vold-Kalman filtering have undesirable traits. Each method has two or more of the following deficiencies: requires measurement or estimate of rotational speed over time, failure to isolate the contribution of crossing orders in the vicinity of the crossing time, large computational expense, end effects. In this work a new approach to the order tracking problem is taken. The Second Order Blind Identification (SOBI) algorithm is applied to synthesized data. The technique is shown to be very successful at isolating crossing orders and circumvents all of the above deficiencies. The method has its own restrictions: multiple sensors are required and sensors must be mounted on a structure that responds quasi-statically to excitation of the rotational system.
McNeill, S., “Considerations for Application of SOBI to Order Tracking,” Journal of Signal and Information Processing 2(1), 33-36, 2011.