SCIENTIFIC AND TECHNICAL AEROSPACE REPORTS

A Biweekly Publication of the National Aeronautics and Space Administration
VOLUME 44, ISSUE 12 - JUNE 20, 2006

04 AIRCRAFT COMMUNICATIONS AND NAVIGATION
Includes all modes of communication with and between aircraft; air navigation systems (satellite and ground based); and air traffic control.

For related information see also 06 Avionics and Aircraft Instrumentation; 17 Space Communications, Spacecraft Communications, Command and Tracking; and 32 Communications and Radar.

20060015656 NASA Ames Research Center, Moffett Field, CA, USA

A Simple Two Aircraft Conflict Resolution Algorithm

Chatterji, Gano B.; [2006]; 1 pp.; In English; AIAA Guidance, Navigation, and Control Conference, 21-24 Aug. 2006, Keystone, CO, USA; No Copyright; Avail.: Other Sources; Abstract Only

Conflict detection and resolution methods are crucial for distributed air-ground traffic management in which the crew in, the cockpit, dispatchers in operation control centers sad and traffic controllers in the ground-based air traffic management facilities share information and participate in the traffic flow and traffic control functions. This paper describes a conflict detection, and a conflict resolution method. The conflict detection method predicts the minimum separation and the time-to-go to the closest point of approach by assuming that both the aircraft will continue to fly at their current speeds along their current headings. The conflict resolution method described here is motivated by the proportional navigation algorithm, which is often used for missile guidance during the terminal phase. It generates speed and heading commands to rotate the line-of-sight either clockwise or counter-clockwise for conflict resolution. Once the aircraft achieve a positive range-rate and no further conflict is predicted, the algorithm generates heading commands to turn back the aircraft to their nominal trajectories. The speed commands are set to the optimal pre-resolution speeds. Six numerical examples are presented to demonstrate the conflict detection, and the conflict resolution methods. Author

Air Traffic Control; Algorithms; Controllers; Missile Control; Trajectories; Proportional Navigation; Information Flow

20060015658 NASA Ames Research Center, Moffett Field, CA, USA

Vortex-Free Flight Corridors for Aircraft Executing Compressed Landing Operations

Rossow, Vernon J.; [2006]; 1 pp.; In English Contract(s)/Grant(s): RTOP 21-150-30-01; No Copyright; Avail.: Other Sources; Abstract Only

A factor that limits airport arrival and departure rates is the need to wait between operations for the wake vortices of preceding aircraft to decay to a safe level. As airport traffic demand increases, creative methods will be needed to overcome the limitations caused by the hazard posed by vortex wakes so that airport capacities can be increased. The problem addressed here is the design of vortex-free trajectories for aircraft as they fly from their cruise altitudes down to their final approach paths and to a landing. The guidelines presented recommend that the flight path of each aircraft in a group executing nearly-simultaneous landings be spaced far enough apart laterally along organized flight paths so that the vortex wakes of preceding aircraft will not intrude into the airspace to be used by following aircraft. An example is presented as to how a combination of straight lines and circular arcs is able to provide each aircraft in a group with a vortex-free trajectory so that all are able to safely form the pattern needed for nearly simultaneous landings on a set of closely-spaced parallel runways. Although the guidelines me described for aircraft on approach, they are also applicable to departure, and to en route operations. Author

Air Traffic; Wakes; Vortices; Approach; Airspace; Free Flight; Runways

Source: NASA