“…In this paper we do not consider only fixed-preview case where information of reference signals is known until a fixed time interval ahead at the current time but also noncausal case where information of reference signals is known until the final time. The author has already presented the necessary and sufficient conditions for the solvability of the stochastic optimal tracking con--29 - It is well known that, for design of tracking control systems, preview information of reference signals is very useful for improving the performance of the closed-loop systems, and much work has been done for preview control systems [2,9,10,[13][14][15][16][17]21,22,24].…”