Positioning and tracking control systems for mobile satellite antenna installations

Abstract

The use of tracking antenna installations (AI) in mobile satellite telecommunications systems (STS) was discussed in the paper. The main purpose of the study is an analytical overview of the methods of positioning and tracking of artificial Earth satellites (AES) and ways of their implementation in AI control systems (CS), meant for working during transport vehicle (TV) movement. The methods of step-tracking (MST), conical scanning and program tracking in terms of their applicability in AI of mobile STS are discussed in the paper. Based on the analysis of parameters of commercial mobile AI, extreme ranges of their parameters for different types of TV were defined. The features of application of open-loop and closed-loop CS of tracking AI were studied. It is shown that open-loop CS provide three or four times higher velocity of angular displacement of AI compared to conventional closed-loop CS, making them more preferable for use in high-speed TV. On the other hand, open-loop CS require highly accurate determining of TV current position, they are susceptible to disturbances from buildings and tend to accumulate errors. Systems with PID and fuzzy controllers are the most widely used in closed-loop CS of tracking AI. Their use allows expanding the control range, improving the performance, enhancing the effectiveness of CS as a whole. The results of the study can be used by experts in the field of control systems for improvement of existing and construction of new mobile AI of STS.