Based on mono - pulse radar system and the analysis of terrain echoes , a geometrical model of air to ground ranging is constituted . by using the signals received from the sum and difference channels of terrain follow radar , a group of the expressions for terrain echoes are educed and characteristics of these echoes are obtained . according to the characteristics of the echoes , the theory and method of pass zero detection of difference channel and its applications are discussed in detail 針對一維單脈沖雷達體制,分析了地形目標回波特性;建立了地形跟隨雷達空地測距的幾何關系;利用雷達收發(fā)信號,導出了地形跟隨雷達和差接收通道的回波信號表達式,進行了波形仿真,得到了地形跟隨雷達的地面散射產(chǎn)生回波在時域中的特性;根據(jù)和差回波特性,闡述了差信號過零點檢測測距的原理和方法及工程實踐中的應用,并給出了真實雷達對外輻射試驗的結果,驗證了文中的仿真。