Minimum deviation of triaxial velocity tracking tactic arithmetic for three-axis turntable

Few real-time methods exist for three-axis turntable tracking when attemping to solve the orientation change of targets. The alt-azimuth and alt-alt methods, which lock the roll and azimuth axes of the turntable, respectively, are mostly utilized. However, these two methods suffer from the problem of tracking in blind zones. In this study, a minimum deviation of triaxial velocity (MDTV) algorithm was proposed to improve the performance of three-axis turntable tracking. A motion model of a three-axis turntable was first established, and the minimum deviation of triaxial velocity was used as the index. The motion of the target, angular position, and angular velocity were then referenced. Finally, a general inverse matrix of the motion model was deduced. The results indicate that triaxial deflections are uniquely determined for distributing the orientation changes of a target into the triaxial tracking evenly, achieving a real-time servo in the three-axis turntable. Compared to the alt-azimuth and alt-alt tracking methods, the MDTV method significantly reduces the angular velocities and accelerations in the tracking process and ensured smooth running when tracking targets are in a blind zone. When a rotating target is tracked, the maximum pointing deviation with the MDTV method is only 15.4% of that with the alt-azimuth method. The study thus proves that the MDTV method can solve the problem of tracking in blind zones and improve the tracking accuracy of a three-axis turntable. © 2019, Science Press. All right reserved.