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MLS Multipath Studies, Phase 3 Final Report, Volume III: Application of Models to MLS Assessment Issues, Part 2
June 8, 1981
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-88,III,PT-2
Summary
This report presents work done during phase 3 of the US national Microwave Landing System (MLS) program toward developing a computer simulation model of the MLS multipath effects, the experimental validation ot the model, and the application of the model to investigate multipath performance of ICAO proposals for the new approach and landing guidance system. The first two volumes of the report presented an overview of the simulation effort as well as describing in detail the propagation and MLS technique mathematical models and their validation by comparison with experimental data. In this volume, we describe the results of comparative simulations for the various MLS techniques in various scenarios and analyze in detail certain multipath performance features which were found to be significant in the scenario simulations. Simulation results are presented for several scenarios, and shadowing of the MLS azimuth by taxiing and overflying aircraft is analyzed. The remainder of the report focuses onmultipath performance factors specific to various individual techniques. These include: (1) the effects of angle data outlier tests and filtering in the TRSB receivers, (2) the effects on the DMLS system due to receiver AGC, receiver motion-induced Doppler shifts, and the use of commutated reference systems, and (3) acquisition/validation algorithms for all three techniques. The report concludes with a summary and suggestions for future work. Part I of this volume consists of Chapters I through IV; Part II contains Chapters V through VIII and the Appendices.
Summary
This report presents work done during phase 3 of the US national Microwave Landing System (MLS) program toward developing a computer simulation model of the MLS multipath effects, the experimental validation ot the model, and the application of the model to investigate multipath performance of ICAO proposals for the new...
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MLS Multipath Studies, Phase 3 Final Report, Volume III: Application of Models to MLS Assessment Issues, Part 1
June 8, 1981
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-88,III,PT-1
Summary
This report presents work done during phase 3 of the US national Microwave Landing System (MLS) program toward developing a computer simulation model of the MLS multipath effects, the experimental validation ot the model, and the application of the model to investigate multipath performance of ICAO proposals for the new approach and landing guidance system. The first two volumes of the report presented an overview of the simulation effort as well as describing in detail the propagation and MLS technique mathematical models and their validation by comparison with experimental data. In this volume, we describe the results of comparative simulations for the various MLS techniques in various scenarios and analyze in detail certain multipath performance features which were found to be significant in the scenario simulations. Simulation results are presented for several scenarios, and shadowing of the MLS azimuth by taxiing and overflying aircraft is analyzed. The remainder of the report focuses on multipath performance factors specific to various individual techniques. These include: (1) the effects of angle data outlier tests and filtering in the TRSB receivers, (2) the effects on the DMLS system due to receiver AGC, receiver motion-induced Doppler shifts, and the use of commutated reference systems, and (3) acquisition/validation algorithms for all three techniques. The report concludes with a summary and suggestions for future work. Part I of this volume consists of Chapters I through IV; Part II contains Chapters V through VIII and the Appendices.
Summary
This report presents work done during phase 3 of the US national Microwave Landing System (MLS) program toward developing a computer simulation model of the MLS multipath effects, the experimental validation ot the model, and the application of the model to investigate multipath performance of ICAO proposals for the new...
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Electronic flight rules: an alternative separation assurance concept
December 31, 1980
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-93
Summary
This report presents results of a study of alternative concepts for tactically separating aircraft in low altitude en route airspace. It describes a concept designated Electronic Flight Rules (EFR) which allows aircraft to fly under instrument meteorological conditions in a manner that retains most of the freedom and flexibility of VFR flight. Feasibility considerations, potential benefits, applicable technologies, and alternative system configurations are evaluated.
Summary
This report presents results of a study of alternative concepts for tactically separating aircraft in low altitude en route airspace. It describes a concept designated Electronic Flight Rules (EFR) which allows aircraft to fly under instrument meteorological conditions in a manner that retains most of the freedom and flexibility of...
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The DABS data link airborne intelligent display operator's manual
September 1, 1980
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-100
Summary
The Federal Aviation Administration is currently evaluating the Discrete Address Beacon System (DABS) which will provide increased air traffic safety in current and future air traffic conditions. In addition to improved surveillance accuracy and reliability, DABS provides a two-way data link between the DABS sensor and all DABS transponder equipped aircraft in view. A DABS data link avionics system, called the Airborne Intelligent Display (AID), was developed by M.I.T. Lincoln Laboratory for the purpose of evaluating and demonstrating initial and future data link applications. The microprocessor-based AID system communicates with the DABS ground sensor through the DABS transponder onboard the aircraft. Data link information included in uplink interrogations to the transponder is decoded in the airborne microprocessor and then made available to the pilot on a high visibility cathode ray tube display. The purpose of this report is to describe the operation and use of the AID.
Summary
The Federal Aviation Administration is currently evaluating the Discrete Address Beacon System (DABS) which will provide increased air traffic safety in current and future air traffic conditions. In addition to improved surveillance accuracy and reliability, DABS provides a two-way data link between the DABS sensor and all DABS transponder equipped...
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Alternate waveforms for a low-cost civil GPS receiver
April 14, 1980
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-86
Summary
This report examines the technical feasibility of alternate waveforms to perform the GPS functions and to result in less complex receivers than is possible with the GPS C/A waveform. The approach taken to accomplish this objective is (a) to identify, after a quick broad overview, a few promising waveforms, (b) to complete the architectural synthesis of a GPS system based on the new waveforms, (c) to analyze the performance of these systems in providing ranging and communication capability and (d) to assess the impact on receiver hardware and software. One conclusion is that the class of pulsed waveform, when combined with emerging matched filter technology, permits the use of a greatly simplified receiver design. Although very specific, the design was intended as a vehicle for performance analysis only and many refinements and alternatives within the same class are possible. Other classes of waveforms such as tome ranging and chirped FM waveforms, although adequate, do not seem superior to the present PN encoded CW waveform for GPS. Finally, if the "alternate" waveform is simply the present C/A waveform but with substantially increased power level, it is shown that with the present designs the performance will be greatly increased or, alternatively, performance margin can be traded for a simplified receiver implementation.
Summary
This report examines the technical feasibility of alternate waveforms to perform the GPS functions and to result in less complex receivers than is possible with the GPS C/A waveform. The approach taken to accomplish this objective is (a) to identify, after a quick broad overview, a few promising waveforms, (b)...
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MLS Multipath Studies, Phase 3, Volume II: Development and Validation of Model for MLS Techniques
February 7, 1980
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-88,II
Summary
This report presents work done during phase 3 of the US national Microwave Landing System (MLS) program toward developing a computer simulation model of the MLS multipath effects, the experimental validation ot the model, and the application of the model to investigate multipath performance of ICAO proposals for the new approach and landing guidance system. This second volume of the report presents the mathematical models and validation data for the MLS techniques which were assessed in detail by the All Weather Operations Panel of the Interational Civil Aviation Organization. The specific techniques modeled are: 1. The Time Reference Scanning Beam (TRSB) system proposed by the United States (US) and Australia, with prime emphasis on the US equipment implementation and field test data, 2. the Doppler scan (DMLS) proposed by the United Kingdom, and 3. the DME Based Landing System (DLS) proposed by the Federal Republic of Germany.
Summary
This report presents work done during phase 3 of the US national Microwave Landing System (MLS) program toward developing a computer simulation model of the MLS multipath effects, the experimental validation ot the model, and the application of the model to investigate multipath performance of ICAO proposals for the new...
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Discrete address beacon system data link
November 8, 1979
Conference Paper
Published in:
3rd Digital Avionics Sys. Conf., 6-7 Nov. 1979, pp. 117-121.
Summary
The Discrete Address Beacon System (DABS) is a surveillance and communication system for air traffic control. DABS is under development as an evolutionary replacement for the FAA's existing Air Traffic Control Radar Beacon System (ATCRBS) to enhance surveillance and provide a digital data communication capability. Each DABS aircraft recognizes and responds with a unique code (its discrete address), thus permitting data link messages to and from a particular aircraft to be accommodated integrally with the surveillance interrogations and replies. The FAA i s currently testing a set of data link applications which will provide aviation services for the initial field implementation of DABS. Link formats, ground interfaces, and systems to support a set of data link applications are also being evaluated for inclusion in the DABS field implementation. The initial data link services include ATC coordination messages and ground-to-air dissemination of weather and aviation related information. Uplink ATC messages include Minimum Safe Altitude Warning (MSAW) Alerts, Altitude Assignment Clearance Confirmation messages, and Takeoff Clearance Confirmation messages. These messages provide the pilot with a supplementary visual confirmation of voice communications. The services also include the capability for the pilot to request weather products derived from National Weather Service (NUS) information. The weather products include surface observations, terminal forecasts, winds aloft, pilot reports, hazardous weather advisories and digitized weather radar Information. Real-time surface measurements from the Enhanced Terminal Information Service (ETIS) are also included. The ETIS i s a flight advisory service which provides the pilot information to assist in conducting safe approaches to (or departures from) an airport. It includes information normally provided by the current Automated Terminal Information Service (ATIS) plus additional data such as weather alerts which pertain to the airport of interest. A DABS data link avionics system has been developed for the purpose of demonstrating and evaluating the initial services. It consists of an airborne microprocessor system with a variety of peripherals and interfaces. The microprocessor communicates with the ground-based equipment via a DABS transponder. Data link information included in the uplink interrogations is processed in the airborne microprocessor and then displayed to the pilot. The display device is a time-shared weather radar indicator with a 256 x 256 bit color graphics capability. Other peripherals include a printer, pilot keyboard, altitude alerter, and a multifunction annunciator capable of speech output.
Summary
The Discrete Address Beacon System (DABS) is a surveillance and communication system for air traffic control. DABS is under development as an evolutionary replacement for the FAA's existing Air Traffic Control Radar Beacon System (ATCRBS) to enhance surveillance and provide a digital data communication capability. Each DABS aircraft recognizes and...
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Air traffic density and distribution measurements
May 3, 1979
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-80
Summary
Results of measurements to determine peak air traffic densities, the spatial distribution of air traffic, and its variation with time, in the Los Angeles Basin and at several locations from Boston to Washington, D.C. are reported. These measurements include only ATCRBS-transponder equipped aircraft. LA Basin traffic densities are shown to be significantly higher than those measured at any other location. The time- and spatial-average density over a circular region of 10 nmi radius reaches a peak value of 0.1 aircraft per sq. nmi in LA. Under comparable conditions the density in Washington, Philadelphia, and Boston reaches 0.02 to 0.04 aircraft per sq. nmi. These measurements, made in 1976, were compared with the LA Basin Standard Traffic Model as to spatial distribution of traffic and absolute density. The results show that the model and the measurement differ by a scale factor of 5:1 (with density being greater in the model) but otherwise agree closely in spatial distribution.
Summary
Results of measurements to determine peak air traffic densities, the spatial distribution of air traffic, and its variation with time, in the Los Angeles Basin and at several locations from Boston to Washington, D.C. are reported. These measurements include only ATCRBS-transponder equipped aircraft. LA Basin traffic densities are shown to...
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MLS Multipath Studies, Phase 3, Volume I: Overview and Propagation Model Validation/Refinement Studies
April 25, 1979
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-88,I
Summary
This report presents work done during phase 3 of the US national Microwave Landing System (MLS) program toward developing a computer simulation model of the MLS multipath effects, the experimental validation ot the model, and the application of the model to investigate multipath performance of ICAO proposals for the new approach and landing guidance system. This first volume of the report presents an overview of the overall simulation results as well as a description of the refined mathematical models and validation of the propagation portion of the simulation. Specific propagation topics include: 1) preliminary results for validation of models for reflections from rough and/or rising terrain based on L-band field data. 2) validation of the models for building reflections based on field measurements at a number of operational airports. 3) validation and refinement of the models for angle guidance system shadowing by obstacles such as buildings and other objects.
Summary
This report presents work done during phase 3 of the US national Microwave Landing System (MLS) program toward developing a computer simulation model of the MLS multipath effects, the experimental validation ot the model, and the application of the model to investigate multipath performance of ICAO proposals for the new...
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The Aircraft Reply and Interference Environment Simulator (ARIES) volume 3: programmer's manual
March 22, 1979
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-87,III
Summary
The Aircraft Reply and Interference Environment Simulator (ARIES) makes possible the performance assessment of a Discrete Address Beacon System (DABS) sensor under its specified maximum aircraft load. To do this ARIES operates upon a taped traffic model to generate simulated aircraft replies and fruit, feeding them to the sensor at RF. Support documentation for ARIES, of which this is the second volume, consists of: Volume 1: Principles of Operation Volume 2: Appendices to the Principles of Operation Volume 3: Programmer's Manual The ARIES Programmer's Manual describes the operation, signal formats and protocols of the Lincoln Laboratory built input/output devices controlled by the Eclipse computer. The descriptions are primarily concerned with the logic of the interface boards that reside in the computer chassis and the formats of the words transferred to and from the computer. The logic of the devices themselves is described only to the extent necessary to understand the interface protocols and data formats.
Summary
The Aircraft Reply and Interference Environment Simulator (ARIES) makes possible the performance assessment of a Discrete Address Beacon System (DABS) sensor under its specified maximum aircraft load. To do this ARIES operates upon a taped traffic model to generate simulated aircraft replies and fruit, feeding them to the sensor at...
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