Multi-path error reduction method and device

According to a multi-path error reduction method and device provided by the invention, the satellite position and the satellite clock error of each satellite are obtained through calculation accordingto the characteristics that the antenna position of a monitoring station in a transformer substation is fixed, objects around the transformer substation are fixed, electromagnetic interference changes regularly and periodically every day and the like and according to the signal observation value of each satellite; the geometric distance from each satellite to the antenna is calculated by utilizing known coordinates of the monitoring station antenna, and a receiver clock difference value is calculated according to the satellite position, the satellite clock difference and the geometric distance of each satellite so as to determine whether a signal observation value of gross error or multi-path effect error or noise error exists or not; a multi-path periodic error correction model is constructed according to the or