Tactical data link (TDL) is one of the key means for enabling real-time exchange of tactical information among weapon systems operated by the Army, Navy, and Air Force. Most messages consist of position information of participating nodes, with latitude and longitude fields designed to enable worldwide operation. Given the limited operational area of Korean army, enabling worldwide operation requires an excessive number of data bits, which cause data overhead and reduced network efficiency. Therefore, in this paper, we investigate the current coordinate transmission methods used in TDL and propose a relative coordinate-based transmission scheme within a designated area to enhance network efficiency. The proposed method is optimized for the operational characteristics of the Korean military and improves both network efficiency and positional accuracy compared to existing TDL.