This paper considers an intelligent transmitting surface (ITS) integrated into a base station and develops a low-overhead maximum a posteriori (MAP) probability channel tracking method for the dominant line-of-sight link between the ITS and the user equipment. We cast the per-block channel as a three-parameter model consisting of the channel amplitude, channel phase, and angle-of-arrival at the ITS. We exploit temporal correlation by updating the priors using the estimates from the previous block. Using only two pilots per coherence block alongside a targeted beam alignment strategy, the proposed method achieves precise channel tracking and attains spectral efficiency close to that achievable under perfect channel knowledge.