Current terminal operations are changing as more terminal Area Navigation (RNAV) routes are defined that aircraft are expected to fly. Previously, arriving aircraft filing a Standard Terminal Arrival Route (STAR) were given vectors to guide them to the runway when the aircraft transitions from the STAR and enters the terminal area. There are, however, efforts underway to extend these STARs as routes in the terminal area that overlay the current traffic patterns resulting from the vectors that controllers give to the aircraft. To achieve the expected benefits from these terminal routes, the controllers will need automation support to assist them in managing the traffic where the routes merge.
Many automation aids could be envisioned to assist the controllers. One particular suite of tools called Spacing of Performance-based Arrivals on Converging Routes (SPACR) has been discussed previously. In that tool set there is a controller decision aide called Converging Route Display Aid (CRDA). The genesis of this decision aid was the Converging Runway Display Aid which is currently embedded in all the Automated Radar Terminal System (ARTS) and Standard Terminal Automation Replacement System (STARS) computers in the United States. In its current form CRDA is a useful decision support tool as part of SPACR to address uncoordinated terminal merges. However, because of the potential geometries of the RNAV routes in the terminal area, CRDA could be more useful with expanded functionality.
In the past certain extensions to CRDA have been investigated. Many of these extensions have resulted in unstable or undesirable dynamics of the "ghost" targets such as jumping and hesitation. This paper will define alternative functional extensions to target aircraft detection and ghost projection that will be useful for RNAV routes and provide the results of analyses performed to determine the effectiveness of such extensions. In particular we will show that if the aircraft conform closely to the RNAV route the "ghost" targets will behave in a manner that should be acceptable to controllers, based upon past controller feedback. We will also show under what conditions the dynamics of the "ghost" targets behave badly.
