Impact of Chinese and European Airspace Constraints on Trajectory Optimization

Abstract

Air traffic trajectory optimization is a complex, multidimensional and non-linear optimization problem and requires a firm focus on the essential criteria. The criteria cover operational, economical, environmental, political, and social factors and differ from continent to continent. Since air traffic is a transcontinental transport system, the criteria may also change during a single flight. Historic flight track data allow observation and assess real flights, to extract essential criteria and to derive optimization strategies to increase air traffic efficiency. Real flight track data from the Chinese and European air traffic show significant differences in the routing structure in both regions. For that reason, reference trajectories of historic ADS-B 24-h air traffic data in China and Europe have been extracted and analyzed regarding horizontal flight efficiency and the most restrictive criteria of trajectory optimization. We found that prohibited areas might be the most powerful reason to describe deviations from the great circle distance in the Chinese air traffic system. Atmospheric conditions, network requirements, aircraft types and flight planning procedures are similar in China and Europe and only have a minor impact on flight efficiency during the cruise phase. In a multi-criteria trajectory optimization of the extracted reference trajectories considering the weather, operational constraints and prohibited areas, we found that flown ground distances could be reduced by 255 km in the Chinese airspace and 2.3 km in the European airspace. The resultant reference trajectories can be used for further analysis to increase the efficiency of continental air traffic flows.

Factors Impacting Chinese and European Vertical Fight Efficiency

“…In [8], reference trajectories have been extracted, using a DBSCAN clustering algorithm. These trajectories represent the main air traffic flows in Eastern China and Europe.…”

“…This reference is calculated for each flight using a flight performance model SOPHIA. Therefore, operational constraints derived in [8], such as prohibited areas, overfly charges and opening schemes are considered.…”

“…38, 800 different trajectories from departure to destination with an update rate of one second. Both data sets are diagrammed in [8] For…”

“…Although China recorded around 4 million international flights in 2019, the figure remains relatively constant at 750 thousand in 2021 [43]. The Chinese air space is composed of 23 restricted areas and 176 prohibited areas [44], which are briefly discussed in [8]. Most of the restricted zones are in China's eastern provinces, which also host most of the country's aviation traffic.…”

“…Even for short point-topoint connections (e.g., Shanghai to Beijing), Asia's demand for wide-body aircraft with high passenger capacity is growing. The Horizontal Flight Efficiency (HFE) has already been compared between China and Europe in [8]. Therein, the most obvious restrictive operational constraints seem prohibited areas in the western part of China, while weather conditions and overfly charges seem to have a minor impact on differences in HFE between both regions.…”