The forth chapter is about the concept of digital maps , and introduce how to gride the digital maps for purpose of firepowers disposal . the fifth chapter import the models of transmission of electromagnetic waves . to clarify the communication ways between communication subsystem and firepowers 第五章根据电磁波的传输特性及其数学模型,建立了战区指挥车(通信中枢)与发射车(火力点)之间的通信模型,以及空域火力覆盖的分层投影分析,这是本算法核心。