Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Traffic analysis or control of aircraft
Reexamination Certificate
2000-07-31
2002-05-21
Nguyen, Tan (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Traffic analysis or control of aircraft
C701S122000, C701S010000, C340S961000, C342S029000
Reexamination Certificate
active
06393358
ABSTRACT:
BACKGROUND OF INVENTION
1. Field of the Invention (Technical Field)
The present invention relates to en route spacing of aircraft.
2. Description of the Prior Art
Note that the following discussion refers to a number of publications by author(s) and month and year of publication, and that due to recent publication dates certain publications are not to be considered as prior art vis-a-vis the present invention. Discussion of such publications herein is given for more complete background and is not to be construed as an admission that such publications are prior art for patentability determination purposes.
En route miles-in-trail (MIT) spacing restrictions are often used to distribute arrival delays upstream of destination airports and to mitigate local areas of en route airspace congestion. National statistics for the U.S. indicate that en route spacing restrictions are applied for approximately 5000 hours per month. These restrictions impact approximately 45,000 flights per month. Current-day practices for MIT-spacing increase controller workload, concentrate traffic unnecessarily, and degrade the performance of conflict-probe (CP) decision support. Today's procedures also result in inefficient conformance actions that directly impact the airspace user. It is estimated that the fuel penalty alone approaches $45 million per year.
A fundamental goal for en route decision support tool (DST) automation is to assist the controller in providing better Air Traffic Control (ATC) service (i.e., greater flexibility to airspace users and fewer ATC-related deviations to user's preferred trajectories) while increasing safety and productivity (i.e., reductions or shifts in controller workload that enable additional productivity). The economic benefits to airspace users come in the form of increased capacity/throughput, reduced restrictions and deviations (time and fuel consumption), and increased flexibility to plan and to fly aircraft.
There are many factors that impact air traffic operations, but primary factors include conflicts and Traffic Flow Management (TFM) flow-rate restrictions. Conflicts relate directly to safety while flow-rate restrictions relate directly to the efficient management of capacity-constrained resources (e.g., runways and sectors). Certainly the safety considerations alone warrant the community's past emphasis on conflict probe technology. However, in terms of mitigating user deviations, particularly in light of the projected rate of traffic growth, it is the flow-rate restriction that is at the core of unlocking user benefits. Although flow restrictions only impact a percentage of flights, the resulting deviations are significant compared to those required for maintaining basic radar separation. Furthermore, the lack of ATC-sector decision support for flow-rate conformance planning and execution results in a significant degradation in the performance of conflict probe. Conflict probe lacks the trajectory “intent” of the controller's plan for flow-rate conformance leading to the “conflict probing” of the “wrong” trajectories (thus increasing the probe's rate of false alarms and missed alerts). This degradation occurs in just the sort of “problem” airspace where the air transport industry needs automation assistance such as conflict probe.
It is particularly interesting to consider en route airspace that is subject to dynamic flow-rate restrictions related to local en route bottlenecks (e.g., sector overload) or the transition to/from high-density terminal-areas. NASA has been active in the development and evaluation of tools and techniques for efficient conflict-free planning in the presence of such constraints. The research is based on Center-TRACON Automation System (CTAS) technology. Erzberger, H., et al., “Design of Center-TRACON Automation System,” AGARD Guidance and Control Symposium on Machine Intelligence in Air Traffic Management, Berlin, Germany, May 1993.
In general, two types of flow-rate restrictions must be considered. These include time-based arrival metering and en route miles-in-trail (MIT) spacing. Arrival metering tools for operations within the U.S. and Europe include the CTAS Traffic Management Advisor (TMA), COMPASS, and MAESTRO with future developments including Multi-Center TMA (U.S.) and Arrival Manager (Eurocontrol). Where operational, arrival metering is generally performed in en route airspace within the last 20 minutes of flight prior to entering terminal airspace. Even with arrival metering operations, many flights will still be subject to MIT-spacing restrictions. MIT-spacing procedures can be expected to play a predominant role for several reasons. The first is the ATC-operational need to merge departures with en route traffic that is “spaced” for downstream capacity limitations. Second, the limited number of arrival-metering sites (i.e., CTAS-TMA-adapted airports) leaves the remaining airports to depend on MIT-spacing procedures. Third, there is a need to occasionally propagate delays upstream of terminal airspace prior to the arrival-metering horizon. As traffic growth outpaces capacity, more flights will be affected by dynamic flow-rate initiatives including MIT-spacing restrictions.
Much of the en route decision support tool effort within the U.S. and Europe has focused on near-term implementations of conflict probe and arrival metering capabilities. There has been some long-term progress towards the development of advanced advisory tools that integrate capabilities for conflict detection/resolution and flow-rate conformance for arrival metering. Green, S. M., et al., “Field Evaluation of Descent Advisor Trajectory Prediction Accuracy for En route Clearance Advisories,” AIAA-98-4479, AIAA Guidance, Navigation, and Control Conference, Boston, Mass., August 1998; Slattery, R. et al., “Conflict-Free Trajectory Planning for Air Traffic Control Automation,” NASA TM-1 08790, January 1994; Green, S. M., et al., “En route Descent Advisor (EDA) Concept,” Advanced Air Transportation Technologies Project Milestone 5.10 Report, September 1999, M/S 262-4, NASA Ames Research Center, Moffett Field, Calif.; and Swenson, et al., “Design & Operational Evaluation of the Traffic Management Advisor at the Fort Worth Air Route Traffic Control Center,” 1st USA/Europe Air Traffic Management R&D Seminar, Saclay, France, June 1997. The Descent Advisor tool of Green et al. (now referred to as the En route/Descent Advisor (EDA)) has undergone many refinements to its controller interface, trajectory planning, and conflict-probe capability to support near-term operational implementation of simple spin-off capabilities. McNally, B. D., et al., “Controller Tools for Transition Airspace,” AIAA-99-4298, AIAA Guidance, Navigation, and Control Conference, Portland, Oreg., August 1999; Erzberger, H., et al., “Conflict Detection and Resolution In the Presence of Prediction Error,” 1st USA /Europe Air Traffic Management R&D Seminar, Saclay, France, June 1997; and Laudeman, I. V., et al., “An Evaluation and Redesign of the Conflict Prediction and Trial Planning Graphical User Interface,” NASA TM-112227, April 1998. However, there has been little effort on near-term controller tools to assist with flow-rate conformance, let alone integration with conflict detection/resolution. Furthermore, there has been no emphasis on the en route spacing problem.
In the U.S., traffic management coordinators (TMCs) within each ATC facility are responsible for coordinating MIT-spacing initiatives within their facility when needed. Dynamic initiatives are either generated within the facility (e.g., local arrival spacing to a non-metered airport), received from neighboring facilities, or coordinated through the ATC System Command Center (ATCSCC). MIT-spacing restrictions are defined in terms of a stream of flights, spacing-reference fix, active period, and a spacing requirement (e.g., 20 nm in trail). Restrictions may also segregate streams by altitude stratum and/or arrival routing.
Once an MIT-spacing restriction is initiated, local TMCs identify the flights w
Erzberger Heinz
Green Steven M.
Nguyen Tan
Padilla Robert M.
The United States of America as represented by the Administrator
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