Publications
Tagged As
Evaluation of Eta model forecasts as a backup weather source for CTAS
August 6, 2001
Conference Paper
Published in:
AIAA Guidance, Navigation and Control Conf.: a collection of Technical Papers, Vol. 3, 6-9 August 2001, pp. 1837-1842.
Topic:
R&D area:
Summary
Knowledge of present and future winds and temperature is important for air traffic operations in general, but is crucial for Decision Support Tools (DSTs) that rely heavily on accurately predicting trajectories of aircraft. One such tool is the Center-TRACON Automation System (CTAS) developed by NASA Ames Research Center. The Rapid Update Cycle (RUC) system is presently the principal source of weather information for CTAS. RUC provides weather updates on an hourly basis on a nationwide grid with horizontal resolution of 40 km and vertical resolution of 25 mb in pressure. However, a recent study of RUC data availability showed that the NWS and NOAA servers are subject to frequent service interruptions. Over a 210 day period (4/19/00-11/11/00), the availability of two NOAA and one NWS RUC server was monitored automatically. It was found that 60 days (29%) had periods of one hour or more where at least one server was out, with the longest outage lasting 13 hours on 9/21/00. In addition, there were 9 days (4%) for which all three servers were simultaneously unavailable, with the longest outage lasting 6 hours on 5/7/00. Moreover, even longer outages have been experienced with the RUC servers over the past several years. RUC forecasts are provided for up to 12 hours, but these are not currently used in CTAS as back up sources (except that the 1 or 2 hour forecasts are used for the current winds to compensate for transmission delays in obtaining the RUC data). Since RUC outages have been experienced for longer than 12 hours, it is therefore necessary to back RUC up with another weather source providing long-range forecasts. This paper examines the use of the Eta model forecasts as a back-up weather sources for CTAS. A specific output of the Eta km model, namely Grid 104, was selected for evaluation because its horizontal and vertical resolution, spatial extent and output parameters match most closely those of RUC. While RUC forecasts for a maximum of 12 hours into the future, Eta does so for up to 60 hours. In the event that a RUC outage would occur, Eta data could be substituted. If Eta data also became unavailable, the last issued forecasts could allow CTAS to continue to function properly for up to 60 hours. The approach used for evaluating the suitability of the Eta model and RUC forecasts was to compare them with the RUC analysis output or 0 hour forecast file, at the forecast time. Not surprisingly, it was found that the RUC model forecasts had lower wind magnitude errors out to 12 hours (the limit of the RUC forecasts) than the Eta model had. Hosever, the wind magnitude error for the Eta model grew only from 9 ft/s at 12 hours (comparable with RUC) to 11 ft/s at 48 hours. We therefore conclude that RUC forecasts should be used for outages up to 12 hours and Eta model forecasts should be used for outages up to 60 hours.
Summary
Knowledge of present and future winds and temperature is important for air traffic operations in general, but is crucial for Decision Support Tools (DSTs) that rely heavily on accurately predicting trajectories of aircraft. One such tool is the Center-TRACON Automation System (CTAS) developed by NASA Ames Research Center. The Rapid...
READ MORE
Radar-based analysis of the efficiency of runway use
August 6, 2001
Conference Paper
Published in:
AIAA Guidance, Navigation & Control Conference, Montreal, Quebec, 6-9 August, 2001, pp. 1-17.
Summary
The air transportation system faces a challenge in accommodating growing air traffic despite an inability to build new runways at most major airports. One approach to alleviating congestion is to find ways of using each available runway to the maximum extent possible without violating safety standards. Some decision support tools, such as the Final Approach Spacing Tool (FAST) that is a part of the Center TRACON Automation System (CTAS), are specifically targeted toward achieving greater runway throughput by reducing the average landing time interval (LTI) between arrivals at a given runway. In order to understand the potential benefits of such innovations, techniques for detecting spacing inefficiencies and estimating potential throughput improvements are needed. This paper demonstrates techniques for analyzing radar data from actual airport operations and using it to validate, calibrate, and extend analyzes of the FAST benefits mechanisms. The emphasis is upon robust statistical measures that can be produced through automated analysis of radar data, thus enabling large amounts of data to be analyzed.
Summary
The air transportation system faces a challenge in accommodating growing air traffic despite an inability to build new runways at most major airports. One approach to alleviating congestion is to find ways of using each available runway to the maximum extent possible without violating safety standards. Some decision support tools...
READ MORE
The design and implementation of the new center/TRACON automation system (CTAS) weather distribution system
August 6, 2001
Conference Paper
Published in:
AIAA Guidance, Navigation and Control Conf.: a collection of Technical Papers, Vol. 3, 6-9 August 2001, pp. 1818-1836.
Topic:
R&D area:
Summary
The National Aeronautics and Space Administration (NASA), working with the Federal Aviation Administration (FAA), is developing a suite of decision support tools, called the Center/TRACON Automation System (CTAS). CTAS tools such as the Traffic Management Advisor (TMA) and Final Approach Spacing Tool (FAST) are designed to increase the efficiency of the air traffic flow into and through Terminal airspace. A core capability of CTAS is the Trajectory Synthesis (TS) software for accurately predicting an aircraft's trajectory. In order to compute these trajectories, TS needs an efficient access mechanism for obtaining the most up-to-date and accurate winds. The current CTAS weather access mechanism suffers from several major drawbacks. First, the mechanism can only handle a winds at a single resolution (presently 40-80 km). This prevents CTAS from taking advantage of high resolution wind from sources such as the Integrated Terminal Weather System (ITWS). Second, the present weather access mechanism is memory intensive and does not extend well to higher grid resolutions. This potentially limits CTAS in taking advantage of improvements in wind resolution from sources such as the Rapid Update Cycle (RUC). Third, the present method is processing intensive and limits the ability of CTAS to handle higher traffic loads. This potentially could impact the ability of new tools such as Direct-To and Multi-Center TMA (McTMA) to deal with increased traffic loads associated with adjacent Centers. In response to these challenges, M.I.T. Lincoln Laboratory has developed a new CTAS weather distribution (WxDist) system. There are two key elements to the new approach. First, the single wind grid is replaced with a set of nested grids for the TRACON, Center and Adjacent Center airspaces. Each and the grids are updated independently of each other. The second key element is replacement of the present interpolation scheme with a nearest-neighbor value approach. Previous studies have shown that this nearest-neighbor method does not degrade trajectory accuracy for the grid sizes under consideration. The new software design replaces the current implementation, known as the Weather Data Processing Daemon (WDPD), with a new approach. The Weather Server (WxServer) sends the weather grids to a Weather Client (WxClient) residing on each CTAS workstation running TS or PGUI (Planview Graphical User Interface) processes. The present point-to-point weather file distribution is replaced in the new scheme with a reliable multi-cast mechanism. This new distribution mechanism combined with data compression techniques greatly reduces network traffic compared to the present method. Other new processes combine RUC and ITWS data in a fail-soft manner to generate the multiple grids. The nearest-neighbor access method also substantially speeds up weather access. In combination with other improvements, the winds access speed is more than doubled over the original implementation.
Summary
The National Aeronautics and Space Administration (NASA), working with the Federal Aviation Administration (FAA), is developing a suite of decision support tools, called the Center/TRACON Automation System (CTAS). CTAS tools such as the Traffic Management Advisor (TMA) and Final Approach Spacing Tool (FAST) are designed to increase the efficiency of...
READ MORE
Weather impacted routes for the Final Approach Spacing Tool (FAST)
August 6, 2001
Conference Paper
Published in:
AIAA Guidance, Navigation and Control Conf.: a collection of Technical Papers, Vol. 3, 6-9 August 2001, pp.1843-1850.
Summary
This paper addresses the issue of developing weather-impacted routes for the Final Approach Spacing Tool (FAST). FAST relies on adaptation data that includes nominal terminal area routes and degrees of freedom to generate optimum landing sequences and runway assignments. However, during adverse weather some adapted routes may become unavailable due to the presence of hazardous weather. If FAST continues to generate trajectories using these routes, its schedule will not be accurate during the adverse weather. The objective of the study was to determine methods for incorporating severe weather products and weather-impacted route data into FAST.
Summary
This paper addresses the issue of developing weather-impacted routes for the Final Approach Spacing Tool (FAST). FAST relies on adaptation data that includes nominal terminal area routes and degrees of freedom to generate optimum landing sequences and runway assignments. However, during adverse weather some adapted routes may become unavailable due...
READ MORE
The radar Correlation and Interpolation (C&I) algorithms deployed in the ASR-9 Processor Augmentation Card (9PAC)
June 29, 2001
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-299
Summary
The Airport Surveillance Radar 9 (ASR-9) is a terminal radar that was deployed by the Federal Aviation Administration (FAA) during the early 1990's at more than 130 of the busiest airports in the United States. The ASR-9 Processor Augmentation Card (9-PAC), developed at MIT Lincoln Laboratory, is a processor board enhancement for the ASR-9 Array Signal Processor (ASP) that provides increases in processing speed, memory size, and programming. The increased capabilities of the 9PAC hardware made it possible for new surveillance algorithms to be developed in software to provide improved primary radar and beacon surveillance performance. The 9PAC project was developed in two phases. Phase I, which addressed the beacon reflection false target problem, was completed, and is currently being deployed nationwide by the FAA on a plug and play basis. Phase II addresses the primary radar surveillance problems, which include automation of the road and ground clutter censoring process, improving the rejection of false targets, and improving the detection and tracking of aircraft targets. The 9PAC also reduces the life-cycle maintenance cost of the ASR-9 in the Phase II configuration, in which a single 9PAC card replaces four ASP cards. This report describes the improvements to the radar Correlation and Interpolation (C&I) process, which is responsible for creating aircraft target reports and filtering out false targets. [Not Complete]
Summary
The Airport Surveillance Radar 9 (ASR-9) is a terminal radar that was deployed by the Federal Aviation Administration (FAA) during the early 1990's at more than 130 of the busiest airports in the United States. The ASR-9 Processor Augmentation Card (9-PAC), developed at MIT Lincoln Laboratory, is a processor board...
READ MORE
Delay causality and reduction at the New York City airports using terminal weather information systems
February 16, 2001
Project Report
Published in:
Project Report ATC-291, MIT Lincoln Laboratory
Summary
Adverse weather accounts for the bulk of the aviation delays at the major New York City airports. In this report, we quantify: 1. Aviation delay reduction with an Integrated Terminal Weather System (ITWS) that incorporates the 30-60 minute predictions of convective storms generated by the Terminal Convective Weather Forecast (TCWF) algorithm, 2. Principal causes of aviation delays with the ITWS in operation, and 3. The extent to which the current delays are "avoidable". We find that improved decision making by the New York FAA users of ITWS provides an annual delay reduction of over 49,000 hours per year with a monetary value of over $150,000,000 per year. Convective weather was found to be the leading contributor to delays at Newark International Airport (EWR) between September 1998 and August 2000. It was found that 40% of the arrival delay in this study occurred in association with delay days characterized by convective weather both within and at considerable distances from the New York terminal area. Of the remaining delay, 27% occurred on days characterized by low ceiling/visibility conditions, while 16% occurred on fair weather days with high surface winds. We also concluded that many of the delays which occur with the current ITWS, over $1,500,000 in one case, could be avoided if the ITWS were extended to provide: 1. Predictions of thunderstorm decay, and 2. Predictions of the onset and ending of capacity limiting events such as low ceilings or high surface winds. These delay causality results are very important for studies of the effectiveness of changes made to the U.S. aviation system to reduce delays at airports such as Newark as well as for prioritizing FAA research and development expenditures.
Summary
Adverse weather accounts for the bulk of the aviation delays at the major New York City airports. In this report, we quantify: 1. Aviation delay reduction with an Integrated Terminal Weather System (ITWS) that incorporates the 30-60 minute predictions of convective storms generated by the Terminal Convective Weather Forecast (TCWF)...
READ MORE
An assessment of the communications, navigation, surveillance (CNS) capabilities needed to support the future Air Traffic Management System
January 10, 2001
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-295
Summary
The purpose of this study was to assess the Communications, Navigation, and Surveillance (CNS) capabilities needed to support future Air Traffic Management (ATM) functionality in the National Airspace System (NAS). The goal was to determine the most effective areas for research and technical development in the CNS field and to make sure the decision support tools under development match future CNS capabilities. The requirements for future ATM functions were derived from high level operational concepts designed to provide more freedom and flexibility in flight operations and from the Joint Research Project Descriptions (JRPDs) that are listed in the Integrated Plan for Air Traffic Management Research and Technology Development. This work was performed for the FAA/NASA Interagency Air Traffic Management Integrated Product Team.
Summary
The purpose of this study was to assess the Communications, Navigation, and Surveillance (CNS) capabilities needed to support future Air Traffic Management (ATM) functionality in the National Airspace System (NAS). The goal was to determine the most effective areas for research and technical development in the CNS field and to...
READ MORE
An operational concept for the Smart Landing Facility (SLF)
January 1, 2001
Conference Paper
Published in:
20th AIAA/IEEE Digital Avionics Systems Conf., 14-18 October 2001, pp. 6.C.2-1 - 6.C.2-8.
Topic:
R&D area:
Summary
This paper describes an operational concept for the Smart Landing Facility (SLF). The SLF is proposed as a component of the Small Aircraft Transportation System (SATS) and is envisioned to utilize Communication, Navigation, Surveillance and Air Traffic Management (CNS/ATM) technologies to support higher-volume air traffic operations in a wider variety of weather conditions than are currently possible at airports without an Air Traffic Control Tower (ATCT) or Terminal Radar Approach Control (TRACON). In order to accomplish this, the SLF will provide aircraft sequencing and separation within its terminal airspace (the SLF traffic area) and on the airport surface. The SLF infrastructure will provide timely and accurate weather and other flight information as well as traffic advisories. The SLF will provide a means to coordinate with nearby TRACONs or Air Route Traffic Control Centers (ARTCCs) to ensure proper integration of its traffic flows with those of adjacent airspace.
Summary
This paper describes an operational concept for the Smart Landing Facility (SLF). The SLF is proposed as a component of the Small Aircraft Transportation System (SATS) and is envisioned to utilize Communication, Navigation, Surveillance and Air Traffic Management (CNS/ATM) technologies to support higher-volume air traffic operations in a wider variety...
READ MORE
Common CHI for en route ATC automation in FFP1 and beyond
October 22, 2000
Conference Paper
Published in:
45th Annual Air Traffic Control Association Conf. Proc., 22-26 October 2000, pp. 237-241.
Summary
Unique computer-human interface (CHI) challenges are arising with the pending deployment of automation developed to assist air traffic controllers and managers. In the US, a set of Free Flight Phase 1 (FFPl) decision-support tools will provide computer generated scheduling and sequencing advice from Traffic Management Advisor (TMA) and conflict probing advice from User Request Evaluation Tool (URET). These tools were originally developed independently using their own CHIs. Recently, the air traffic community requested that future tools be implemented as an integrated functionality with a consistent look and feel modeled on Eurocontrol's innovative Operational Display and Input Development (ODID) IV. M.I.T. Lincoln Laboratory presented an initial comparative study of FAA and Eurocontrol tools that identified several key inconsistencies between the newly deployed Display System Replacement (DSR), the upcoming FFPl and the future ODID-like CHIs at ATCA 1999. This paper expands the survey to add the ETMS Traffic Situation Display (TSD) and to include a comparison of all look and feel aspects of each tool ranging from the purpose and system requirements to the display and coordination features. Excerpts from the completed survey are presented in Table 1, accompanied by preliminary descriptions of resulting human factors issues that need resolution to achieve a common CHI for future air traffic control and management. In support of the FAA, the Laboratory is now applying the findings from this effort and previous controller testing in collaboration with MITRE CAASD to identify and assess CHI features to be used for a demonstration of integrated operational concepts. This effort, along with continued CHI requirements testing, communication with FAA vendors and concept demonstrations conducted in coordination with the air traffic community will lead to a comprehensive list of prioritized issues regarding a common CHI.
Summary
Unique computer-human interface (CHI) challenges are arising with the pending deployment of automation developed to assist air traffic controllers and managers. In the US, a set of Free Flight Phase 1 (FFPl) decision-support tools will provide computer generated scheduling and sequencing advice from Traffic Management Advisor (TMA) and conflict probing...
READ MORE
Measurements of ADS-B extended squitter performance in the Los Angeles basin region
October 7, 2000
Conference Paper
Published in:
19th AIAA/IEEE Digital Avionics Systems Conf., Vol. 2, 7-13 October 2000, pp. 7.B.1-1 - 7.B.1-8.
Summary
The Los Angeles Basin ADS-B Measurement Trials provided a quantitative assessment of the existing interference environment at 1090 MHz and the surveillance performance of Mode S Extended Squitter in that environment. Redundancy in the measurement equipment and in the flight configurations chosen during the trials provided extensive cross checking capability, and greatly increased the integrity of the results. ATCRBS reply rates as high as 40,000/second above -90 dBm were measured. The corresponding aircraft distribution and 1030 MHz interrogation rates correlated well with these measurements. A wide range of scenarios were captured to measure the airborne and ground-based reception of ADS-B Extended Squitters emitted by airborne sources. Air-to-air ranges of greater than 100 nmi were routinely observed, and comparison with ADS-B MASPS requirements showed that all airborne requirements were met in the scenarios flown. Air-to-ground reception rates were routinely better than the update rates provided by either en route or terminal radars at ranges beyond 150 nmi. Ground-to-air (uplink) performance was adequate to support transmission of ADS-B or other information in broadcast formats within approximately 60 nmi of the ground station. Finally, these measurements are a valuable source of validation and refinement data for the various models used to predict Extended Squitter performance in current and future scenarios.
Summary
The Los Angeles Basin ADS-B Measurement Trials provided a quantitative assessment of the existing interference environment at 1090 MHz and the surveillance performance of Mode S Extended Squitter in that environment. Redundancy in the measurement equipment and in the flight configurations chosen during the trials provided extensive cross checking capability...
READ MORE