Research on operational protection area of ILS localizer

Precise delineation of the instrument landing system (ILS) localizer operational protection area is essential for maintaining navigation signal integrity and ensuring safe aircraft approaches. This study investigates the definition and evolution of operational protection area by synthesizing national standards and ICAO Annex 10 requirements. By employing computational electromagnetic simulations with the A380-800 model, we analyze the multipath interference generated by the aircraft and assess the impact of varying aircraft attitudes on signal stability. The findings provide quantitative data that supplement ICAO Annex 10 guidelines and offer a practical engineering demonstration for complex airport environments. Additionally, the study proposes optimized methodologies for site protection and delineation, providing valuable references for airport planning and operational management.