t is necessary to measure the instrument height accurately in trigonometric levelling, especially in measuring dot altitude accurately with infrared distance gauge.
三角高程测量，特别是用红外测距仪、全站仪精确测定点的高程，都需要精确测定仪器高。
The microvibration control system of high high-accurate instrument is discussed in detail.
对高精密仪器微振动控制技术进行了综合阐述,介绍了振动主动控制技术的发展,评价了主动控制中各种致动器和传感器,重点分析了各种微振动隔振平台的构成和控制效果。