Instrument landing system ( ils ) a standard icao precision landing aid to provide accurate azimuth and descent guidance signals for use by aircraft for landing on the runway under adverse weather conditions 这是国际民航组织指定的标准精确著陆导向设备，提供准确的方向指示及下降指引讯号，即使在恶劣的天气状况下，航机亦能安全地在跑道上降落。
The microwave landing system ( mls ) has higher performance and more advantages than the instrument landing system ( ils ) , which will be adopted as the international standard landing system to replace ils in this year 并且，由于微波着陆系统工作于微波段，还可以减小多径效应。因此，和仪表着陆系统相比，微波着陆系统是一种性能比较优越的着陆导航系统。
Aom tells very instrument pilot under what visibility ( in terms of runway visual range ( rvr ) ) and or cloud ceiling can the aircraft take off , and under what visibility ( again in terms of rvr ) and visual reference can the aircraft continue the approach to land from the decision altitude ( for precision approaches , e . g . instrument landing system ( ils ) ) or from the minimum descent altitude ( for non - precision approaches ) . there are a number of factors affecting the values of aom 机场最低飞行条件让每名按仪表驾驶的飞行员知道，航空器在什么能见度以跑道能见距离来说及或云幕高度下才可起飞；以及航空器在什么能见度以跑道能见距离来说及目视基准下，才可从决断高度用于如使用仪表著陆系统的精确进场或最低下降高度用于非精确进场继续进场著陆。
Based on well understanding the principles and characteristics of the radio beacon of centimetric wave instrument landing system made in russia , the this paper brings forward a scheme to domesticalize the russian system and gives its detailed designs of software and hardware , in which the reliability and serviceability are fully considered 本文在深入研究俄制分米波仪表着陆系统工作原理和技术特性的基础上，提出了该系统的国产化设计思想和研制方案，进行软、硬件的详细设计，在设计中充分考虑了系统的可靠性与可维修性。
