Aircraft 4-D Constant Velocity Control System

Abstract

A 4-D system for sequencing of aircraft in a traffic controlled environment is developed. A closedform approximation for determination of the constant airspeed necessary to fly a fixed ground path consisting of straight line and constant radius arc segments is shown to have accuracy of better than 0.1%. Heading and bank angle required on the turns are also computed. These calculations are used as commands to an aircraft and are periodically updated to provide for elimination of errors accumulated during flight. The concept is capable of being implemented over a broad spectrum of aircraft under active control from those with full RNAV autopilots, to those under radar vector control where commands are relayed verbally from a traffic controller. The system capability is demonstrated in a simulation of a modern transport aircraft with a typical autopilot and auto throttle, navigation information, and computer to process the command equations. Sequencing accuracies within a few seconds are obtained when the aircraft is subjected to combined unsteady winds (gusts) and errors in the knowledge of the steady wind conditions.