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This paper presents simple and explicit formulae of an ‘observer‐based H∞ controller’ for linear time‐delay systems. Based on the LMI approach, we design a dynamical controller which guarantees the asymptotic stability of the closed‐loop system and reduces the effect of the perturbation to a prescribed level. The main contribution of the paper is to provide closed‐loop stability analysis when the system time delay is unknown. We give delay‐dependent and delay‐independent stability results. The proposed method is illustrated by examples. The paper completes the work of the same authors. Copyright © 2000 John Wiley & Sons, Ltd.

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A new technique, Point Merge, for merging aircraft without vectoring in terminal areas (TMA), is modelled, and used in fast-time simulations. Four arrival traffic streams are merged for landing on a single runway. A method for designing fast-time models of vectoring and Point Merge is proposed and validated using real-time simulation trajectories. Relative performances of fast-time simulations of the corresponding models are compared. Interactions with departure traffic are also assessed. Results show the Point Merge model reduces: mean controller task load (20±1%), the number of instructions to pilots (~30%), and fuel consumption (170±14 kg), compared with vectoring.

This air traffic management research study analysed the interaction between a potential future airborne spacing application and an existing Airborne Collision Avoidance System (ACAS). The time-based airborne spacing application 'merge behind' was simulated in fasttime for a range of merge angles (45°, 90°, 135° and 180°), target spacing times (60 and 90 s) and altitudes (6,000 and 11,000 feet) under turbulent wind and extreme entry conditions. Trajectory pairs were analysed for potential collision alerting conditions using an ACAS simulator based on Traffic Alert and Collision Avoidance System (TCAS) II version 7 logic. Results show how, with realistic turn anticipation, the TCAS estimated time to go to Closest Point of Approach (CPA) decreased as merge angle was increased and as target spacing was reduced, but still remained above the Traffic Advisory (TA) and Resolution Advisory (RA) thresholds for the duration of all trials.