在DEM数据的基础上对地面进行雷达单元的划分，对各个单元进行遮蔽处理，根据雷达和地面的几何关系，通过计算获得后向散射系数，并画出后向散射系数图-In the DEM data, based on ground-based radar unit for the division to cover for each unit processing, radar and ground based on the geometric relationship between the obtained by