Trajectory Specification for Terminal Airspace: Conflict Detection and Resolution

Abstract

Trajectory Specification is a method of specifying aircraft trajectories with tolerances such that the position at any given time in flight is constrained to a precisely defined bounding space. The bounding space is defined by tolerances relative to a reference trajectory that specifies position as a function of time. The tolerances are dynamic and are based on the aircraft navigation capabilities and the traffic situation. Trajectory Specification can guarantee safe separation for an arbitrary period of time even in the event of an air traffic control (ATC) system or datalink failure. It can help to achieve the high level of safety and reliability needed for ATC automation, and it can reduce the reliance on tactical ATC backup systems during normal operation. This paper presents algorithms and software for detecting and resolving conflicts between specified trajectories in the terminal airspace serving a major airport. In a fast-time simulation of a full day of traffic in a major terminal airspace, all conflicts were resolved in near real time, demonstrating the computational feasibility and the preliminary operational feasibility of the concept.

Trajectory generation based on power for urban air mobility

“…As mentioned in the Introduction, the methods used in this paper are based in part on the Trajectory Specification concept (Paielli, 2022), which allows the time steps of the reference trajectory to vary in size, typically being larger in steady-state flight than otherwise. That allowance for varying time steps is used here to set the power level by computing the time step between discrete points in 3D space that yields the specified power at that time.…”

“…A route is the vertical projection of a trajectory onto the geodetic surface of the earth. In the Trajectory Specification (TS) concept (Paielli, 2022), a route is specified as a sequence of waypoints on that surface and a turn radius associated with each waypoint. The TS algorithm takes those route parameters and constructs a detailed route representation consisting of alternating straight and turn segments.…”

“…The methods used in this paper are based in part on the Trajectory Specification (TS) concept (Paielli and Erzberger, 2019;Paielli, 2022). TS is a method of specifying a trajectory with explicit tolerances relative to a reference trajectory such that the position at any given time in flight is constrained to a precisely defined volume of space as shown in Figure 1.…”