Spatial Boundary Analysis of GNSS Interference with Adjacent Interference Sources

‍ ‍The Global Navigation Satellite System （GNSS） has been widely used over the past few decades. However， various new types of radio interference sources have emerged， affecting the robustness of GNSS application systems. GNSS plays an increasingly important role in civil aviation operations. Research on localizing interference sources affecting GNSS signals used by civil aviation aircraft has been conducted both domestically and internationally. Existing studies often assume that only a single interference source exists within the analysis space. In reality， there are instances where multiple GNSS interference sources exist near an interference source that disrupts civil aviation GNSS signals. Analyzing the spatial boundaries affected by these interference sources is crucial for guiding the localization and effective elimination of interference. In this paper， we address the influence of adjacent GNSS interference sources on the interference spatial range of a primary GNSS interference source under various parameters. We propose a method to analyze the differences in interference spatial ranges caused by nearby interference sources and systematically analyze the variations in these ranges. A significant difficulty in this analysis is that the interference spatial range is influenced by numerous factors， some of which are interrelated. Firstly， we model the received interference signal power of an airborne GNSS receiver at a specific position， calculating the received power in different spatial positions both with and without the presence of an adjacent interference source. Secondly， we analyze the influencing factors on the interference spatial range and their specific impacts. Finally， we introduce two quantitative indices based on the modified Hausdorff distance between the curves： the mean value of boundary difference and the standard deviation of boundary difference. These indices are used to quantitatively evaluate the differences in interference spatial range under varying conditions， with or without the presence of adjacent interference sources. Through quantitative evaluation， we identify scenarios where the presence of adjacent interference sources minimally impacts the interference spatial range and where localization results derived from models that assume a single interference source may incur little bias. Conversely， we also determine situations where adjacent interference sources significantly influence the interference spatial range， potentially leading to considerable errors in localization results based on single interference source assumptions. Experimental results show that when the antenna pattern of the interference source is established， the power ratio of the adjacent interference source to the main source， the power level of the main interference source， the distance between the sources， and the analysis height layer all affect the interference spatial range. Our analysis provides criteria for lesser boundary differences in the interference spatial range with and without adjacent interference sources surrounding the primary interference source， utilizing the mean and standard deviation of boundary differences. The findings regarding the characteristics of the interference spatial range under various conditions and instances of lesser boundary differences can assist in effectively localizing and eliminating interference sources in scenarios where multiple interference sources are present.