Measuring and Modeling ICAO’s PBCS Performance Metrics

As airspace use is becoming denser and more diverse, communication links play a key role in current visions on future airspace. However, the integration of digital communication links into the airspace system makes them subject to stringent requirements and assessments. To allow for easier safety assessment of communication links, regional and national regulators are formulating requirements in the language of the Performance Based Communication and Surveillance (PBCS)) framework defined by the International Civil Aviation Organization (ICAO). Unfortunately, these requirements mismatch performance metrics that communication engineers are used to. To date, little is known on how to prove compliance with the regulatory requirements scientifically. In this paper, a method to scientifically measure PBCS availability and continuity is proposed. Furthermore, an analytic formula to relate these metrics to more common communication metrics of network availability, message error rates and delay is presented. Basic properties such as the impact of a single link on end-to-end performance are analyzed and lower bounds are established. It is verified by means of simulation that the measurement framework correctly captures availability and continuity and that the analytic formula, as well as the derived bounds, can be used to predict measurements during operations.