高度維持監視システムの研究

抄録

This paper presents the altitude surveillance system (ASS), i.e., its hardware specification, software design, performance evaluation and interim surveillance results using real SSR Mode-C data.

Steadily increasing air traffic in recent years is causing delays in several areas, therefore ICAO is planning to reduce the vertical separation from 2,000ft to 1,000ft between FL290 and FL410. It consequently increases usable cruising levels. Based on the collision risk assessment, ICAO RGCSP concluded in 1988 that application of a 1,000ft vertical separation minimum was technically feasible, on the condition of an introduction of system performance monitoring etc..

ASS is a super-mini-computer based height monitoring system. It checks assigned altitude deviations (AAD), bit-errors, level-offs and abnormally decoded Mode-C signals due to the multipath effect. AAD is detected as the difference between received Mode-C and assigned altitude when an aircraft cruises, or the differences between Mode-C and smoothed height trajectory when an aircraft climbs or descends. Level-off maneuvers are classified into anticipated types by a pattern matching method.

The screening parameters of monitor software are adjusted to meet the purpose of the system by its performance evaluation using real SSR Mode-C data. As an example of the result, it was found that an average of 12 among 833 aircraft deviate more than 300ft in one day.