Risk Assessment of Mid-air Collision Based on Positioning Performance by Navigational Aids

Algorithms of positioning by navigational aids are widely used as an alternative to Global Navigation Satellite System on-board of large airplanes. Distance measuring equipment is a commonly used navigational aid for alternative positioning by a pair of measured ranges. Errors of range measuring are directly connected with airplane localization in airspace and have primary influence in airplane trajectory maintaining as well as ensuring the required level of air traffic safety. The impact of errors of on-board positioning system into aviation safety is represented in the paper. A mid-air collision category of aviation safety is assessed based on risk of airplane unintentional deviation from planned location due to influence of on-board positioning system errors. Represented approach is grounded on location of a bivariate probability density function at each airspace user location and estimation of a probability of getting two airspace users within the same safety region. Airplanes separation minimums are used as size of the safety region. Numerical demonstration is provided by live air traffic data shared by Automatic Dependent Surveillance-Broadcast message and received by Software Defined Radio within a part of Ukrainian airspace volume. Risks of mid-air collisions for each pair of airspace users are estimated.