测量空中或者地面两个高速飞行物体之间的距离,特别是二者接近时的最近距离,例如导弹对飞机的脱靶量,以在通常采用电磁探测、红外线探测、声学测量和光学观测等方法.六十年代发展起来的,射线距离指示器是一种利用放射性同位素的新颖仪器.第一,它在测量中避开了使用无线电频率, Measure the distance between two high-speed flying objects in the air or on the ground, especially the closest distance between them. For example, missile miss distance to the aircraft is usually measured by electromagnetic detection, infrared ray, acoustic measurement and optical observation. Developed in the 1960s, the ray distance indicator is a novel instrument that uses radioactive isotopes. First, it avoids the use of radio frequencies in measurements,