To eliminate the significant data redundancy and resource waste caused by AIS repeater stations operating within shore-based signal coverage, the paper introduces a protocol-based intelligent switching mechanism. This mechanism utilize AIS Message 4, unique to base stations, as a sign to determine if a vessel is within a shore-based network. The repeater station validates these messages via MMSI prefix matching and optional geofencing, then uses a state transition model driven by preset time, count, and silence thresholds to autonomously switch between repeating and paused states. This source-level filtering ensures the device is active only in signal blind spots, drastically cutting communication costs and operational burdens. By preventing data redundancy, the system reduces the processing load on the core AIS network and boosts overall efficiency, enabling a low cost, highly effective extension of seamless vessel surveillance to the network edge.