Validation of Performance-Based Aeronautical Surveillance Requirements Based on Empirical Traffic Flow Analysis

Abstract

Secondary Surveillance Radar (SSR) and Automatic Dependent Surveillance-Broadcast (ADS-B) operating in the 1030/1090 MHz bands are fundamental components of modern Air Traffic Management (ATM). However, the increasing traffic density in metropolitan airspaces poses significant challenges to the integrity of these surveillance infrastructures due to signal congestion and garbling. This study presents a comprehensive analysis of the signal environment over the Japanese archipelago, using raw digitized waveforms captured during flight experiments with a research aircraft. To establish a correlation between physical signal load and operational density, we adopted a grid-based spatial analysis. Our empirical results reveal a distinct non-linear relationship between aircraft density and frequency occupancy. While moderate-density areas exhibited stable occupancy levels, regions categorized as “High-High” density—particularly near the Nagoya and Tokyo metropolitan areas—showed aggressive spikes in signal load. A key finding is that the aggregate signal occupancy reached peaks of over 1.0%, driven significantly by low-altitude traffic within Terminal Control Areas (TMAs) that is “hidden” in en-route density maps. This level of congestion, equivalent to approximately 80 transmissions per second, suggests that the 1090 MHz channel is approaching its structural capacity limits in specific high-density nodes. These findings provide a quantitative evidence base for future Performance-Based Surveillance (PBS) standards and emphasize the critical need for cumulative signal environment monitoring to ensure the long-term sustainability of aeronautical surveillance systems.