Accuracy Analysis of a Pointing Mechanism for Communication Applications

In this paper, a detailed accuracy analysis for the orientation of an innovative open-chain pointing mechanism is carried out, employing methods for indirect measurements. The particular shape of the mechanism exhibits the advantage of high structural stiffness and different pointing accuracy in comparison with a standard orthogonal axes gimbal. With the aim of finding out advantages and drawbacks as regard the accuracy of the proposed pointing mechanism, an accuracy analysis is performed through three different methods of uncertainty expression and propagation based on the probability theory or the theory of evidence. The proposed pointing mechanism, in comparison with the standard orthogonal axes gimbal, exhibits a considerable lower uncertainty for two of the three Euler angles that are used for the end-effector orientation expression and a higher uncertainty for the third Euler angle. Thus, the proposed mechanism could be particularly suited for pointing directional antennas, allowing the employment of high-data-rate communication systems. This result is strengthened by the fact that the accuracy analysis was performed with different uncertainty expression and propagation methods, which take into account only random effects or both random and systematic effects.