Analysis of the impact of site protection area terrain roughness on signal quality

The Glide Path (GP) is an integral part of the Instrument Landing System(ILS), working in conjunction with the onboard receiver to provide glide guidance information for aircraft approaching and landing. The GP operates in the 328.6 to 335.4MHz ultra-high frequency range, and signal transmission mainly relies on the reflection of the protected area in front of the antenna. The GB6364-2013 "Electromagnetic environment requirements for aeronautical radio navigation stations" and MH/T4003.1 "Specification for aeronautical communication navigation and surveillance station siting criteria-Part1:Navigation" have strict regulations on the site protection areas A, B, and C of the GP.On the basis of computer simulation modeling, this article conducts simulation analysis on the influence of terrain roughness in the protection area of the GP on the glide angle, threshold crossing height, and glide slope structure of the GP.