Low Tracking Error Research Articles

Improved allan variance real-time processing system to measure frequency tracking error of heterodyne optical phase-locked loops

The performance of an Allan variance measuring system was drastically improved by employing time interval analysis incorporating a beat frequency method. It was used to evaluate the performance of a heterodyne optical phase-locked loop with a very low optical frequency tracking error of 0.4 mHz at the integration time of 70 s. Advantages of the system are precise measurement for highly stable frequency sources with good reproducibility and simple structure

Congruent and spurious motion in the learning and performance of a compensatory tracking task.

The importance of congruent and spurious yaw motion in compensatory tracking by eight airline pilots was examined. The pilots, seated erect in the Ames Man-Carrying Rotation Device (MCRD), tracked with k/s+1 and k/s(s+1) vehicle dynamics in fixed- and moving-base simulation. Following the learning phase of the experiment, five levels of spurious angular acceleration were superimposed on the motion of the MCRD. Learning of the tracking task was found to be a function of both vehicle dynamics and mode of simulation. The presence of congruent motion information reduced learning time in k/s(s+1) vehicle dynamics and resulted in lower tracking error in both vehicle dynamics. The spurious angular accelerations resulted in an increase in pilot tracking error; however, the relationship between the magnitude of the acceleration and its effect was highly complex. The data suggest that the minimal disturbance level for spurious angular accelerations during tracking is below 0.4°/sec.2.