夜间低空导航吊舱的核心是地形跟随雷达，其测距系统准确地完成地形跟踪和测距；从而保证歼击机能够超低空飞行，完成其作战任务。文章详细介绍了为导航吊舱系统配置的测距系统．论述了其系统结构、测距原理和定时系统的设计。 At the core of night low-altitude navigation pods is the terrain following radar, whose ranging system accurately tracks and surveys the terrain; so as to ensure the fighter can fly at low altitude and complete its combat missions. The article details the ranging system configured for the navigation pod system. Discusses its system structure, ranging principle and timing system design.