Potential Impact of GNSS Positioning Errors on the Satellite-Navigation-Based Air Traffic Management

The traditional air traffic management (ATM) is transforming to the Communication, Navigation, Surveillance/ATM, which relies on accurate Global Navigation Satellite System (GNSS) navigation service, particularly during the final approach and landing phases. However, in the event of adverse space weather, there may be a significant increase in total electron contents (TECs) and irregularities in the ionosphere, which may cause considerable GNSS positioning errors. As a result, the aircraft navigation mode has to be switched from satellite navigation to ground navigation, which will reduce the airport acceptance rate and cause an imbalance between flight demands and airport capacity. The ATM authority will have to make tactical measures to remedy the problem, such as flight rescheduling and even cancellations. Hong Kong International Airport (HKIA) is one of the busiest airports in the world and Hong Kong, located in the equatorial ionosphere anomaly region, is prone to impacts of space weather. Thus, we have created a hypothesis scenario in this study by analyzing projected flight data from the HKIA during a simulated geomagnetic storm. Calculation results show that without an ionospheric delay forecast, the potential financial costs related to airlines due to flight delays, cancellations, and diversions could be over 2 million Euros. These costs decrease with an increased lead time of ionospheric delay forecast and the inaccurate ionospheric delay forecast can also result in significant extra costs. We also estimate the time cost of flight delays to passengers can be between 1.7 and 3.0 million Euros.