A Methodology to Elaborate Aircraft Localization Requirements for Airport Navigation

The general increase in air traffic and the complexity of modern airport layouts have led to think about new system opportunities to assist pilots during maneuvers on airport surface. Two applications will be considered in this paper: guidance and control. Guidance application provides indication to the pilot to navigate on the airport surface whereas control application provides steering indications. These two applications will allow the pilot to drive under low visibility conditions. This assistance is based on the knowledge of the aircraft position on the airport surface. However, precise requirements on aircraft localization service on the airport surface, in terms of accuracy, integrity, continuity and availability, have not been completely expressed by existing standards. This paper proposes a methodology to derive these requirements based on FHA (Functional Hazard Analysis) method. FHA is a predictive technique whose goal is to explore the functional effects of failures on parts of the system. It results in the suggestion of 95% accuracy, integrity risk, HAL (Horizontal Alert Limit) and TTA (Time To Alert) requirements according to the visibility conditions for the different operations.