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Provisional message formats for the DABS/NAS interface, revision 1

October 10, 1974
  |
Project Report
Author:
David Reiner
…
Published in:
MIT Lincoln Laboratory Report ATC-33,I
Topic:
surveillance
R&D area:
R&D group:

Summary

This document defines formats for messages which are to be transmitted between DABS and NAS facilities (en route or terminal). These messages include one-way Surveillance Reports to NAS and two-way Communications Messages. The latter support data link functions between NAS and DABS equipped aircraft, as well as aiding in the monitoring and control of DABS sensors. These message formats will be used in the design and construction of interface equipment and ground data links for prototype system test and evaluation at NAFEC during Phase II of the DABS Development Program; and, with modifications resulting from this test and evaluation effort, will form the basis for the operational implementation of DABS. This document supersedes FAA-RD-74-63, dated 25 April 1974.
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Summary

This document defines formats for messages which are to be transmitted between DABS and NAS facilities (en route or terminal). These messages include one-way Surveillance Reports to NAS and two-way Communications Messages. The latter support data link functions between NAS and DABS equipped aircraft, as well as aiding in the...

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Provisional message formats for the DABS/NAS interface, revision 1

Simulation of the DABS sensor for evaluating reply processor performance

September 16, 1974
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Project Report
Author:
Robert J. McAulay
…
Published in:
MIT Lincoln Laboratory Report ATC-28
Topic:
surveillance
R&D area:
R&D group:

Summary

This report describes the elements of a simulations program that was designed to perform a realistic evaluation of a variety of reply processing techniques, antenna design parameters and receiver characteristics for a DABS sensor. The reply processing techniques are limited to the generation of information bit and monopulse off-boresight azimuth estimates for DABS downlink messages. The report describes the detailed characteristics of two elements of the simulation program; the data generator and reply processor, and the high degree of versatility incorporated within these elements to allow for a great many performance tradeoff studies.
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Summary

This report describes the elements of a simulations program that was designed to perform a realistic evaluation of a variety of reply processing techniques, antenna design parameters and receiver characteristics for a DABS sensor. The reply processing techniques are limited to the generation of information bit and monopulse off-boresight azimuth...

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Simulation of the DABS sensor for evaluating reply processor performance

New techniques applied to air-traffic control radars

June 1, 1974
  |
Journal Article
Author:
Charles E. Muehe
…
Published in:
Proc. IEEE, Vol. 62, No. 6, June 1974, pp. 716-723.
Topic:
air traffic control
R&D area:
R&D group:

Summary

During the past two years a program has been carried out to show how new techniques can greatly improve the performance of radars used for air-traffic control. A survey of problems associated with presently used radars was undertaken. This survey indicates that primary radar in an automated air-traffic control system can be made significantly more effective by the use of new techniques. The radar's handling of extraneous reflections (clutter) is critical to its performance. Three types of interfering clutter were found to predominate: ground clutter, weather clutter, and angels. Angels are generally accepted to be radar returns from flocks of birds. In addition, second-time-around clutter is often troublesome. For each type of clutter, all known remedies for improving the signal-to-clutter ratio were studied and radar systems were configured using appropriate sets of remedies. Some specific solutions incorporated in the resulting radar systems are: a) the use of linear large dynamic range, near-optimum digital signal processors to filter signals from clutter, b) the use of electronically step-scanned antennas to improve the correlation of aircraft and clutter returns from pulse to pulse, c) the use of multiple PRF's instead of staggered PRF's together with coherent transmitters to keep second-time-around clutter returns well correlated while still overcoming blind speeds, d) the use of a fine grained ground clutter map to give superclutter visibility on tangential targets, and e) the use of lower operating frequencies to greatly reduce weather and angel returns. Two demonstration radar systems have been implemented, an S-band radar using a mechanically rotating antenna and a UHF radar using an electronically step-scanned cylindrical antenna. Experimental results are described.
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Summary

During the past two years a program has been carried out to show how new techniques can greatly improve the performance of radars used for air-traffic control. A survey of problems associated with presently used radars was undertaken. This survey indicates that primary radar in an automated air-traffic control system...

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New techniques applied to air-traffic control radars

Provisional message formats and protocols for the DABS IPC/PWI display

May 24, 1974
  |
Project Report
Author:
Peter H. Robeck
…
Published in:
MIT Lincoln Laboratory Report ATC-35
Topic:
surveillance
R&D area:
R&D group:

Summary

This document specifies provisional formats for the data link portion of the ?signals-in-space? which are part of the DABS interrogations and replies. Also included is a discussion of the characteristics that these signals assume while transmitted from the transponder proper to the instrument which delivers the messages to the pilot. Specifically, formats, algorithms, and protocols are assigned to serve the IPC (lntermittent Positive Control), PWI (Proximity Warning Indicator), and ATC (numerical indicator) functions. The protocol and algorithm for the pilot acknowledgment link is also included in this paper.
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Summary

This document specifies provisional formats for the data link portion of the ?signals-in-space? which are part of the DABS interrogations and replies. Also included is a discussion of the characteristics that these signals assume while transmitted from the transponder proper to the instrument which delivers the messages to the pilot...

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Provisional message formats and protocols for the DABS IPC/PWI display

Morphology of ionospheric scintillation

May 21, 1974
  |
Technical Report
Author:
Robert K. Crane
Published in:
MIT Lincoln Laboratory Report TN-1974-29
Topic:
communications
R&D area:
R&D group:

Summary

This report is directed toward providing information to communication systems designers first about scintillation as observed in a single experiment, second about the adequacy of the existing models used to interpret scintillation data, and finally about the variation of scintillation with geophysical parameters.
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Summary

This report is directed toward providing information to communication systems designers first about scintillation as observed in a single experiment, second about the adequacy of the existing models used to interpret scintillation data, and finally about the variation of scintillation with geophysical parameters.

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Morphology of ionospheric scintillation

Provisional message formats and protocols for the DABS 32-character alphanumeric display

May 20, 1974
  |
Project Report
Author:
Jerry D. Welch
…
Published in:
MIT Lincoln Laboratory Report ATC-36
Topic:
surveillance
R&D area:
R&D group:

Summary

Formats and protocols are described for tactical ATC displays to be driven by the Standard Message interface of a DABS transponder and capable of handling a succession of data transmissions, each of which is individually acknowledged via a transponder reply before the transmission of the succeeding segment. Specific codes are defined for a display device of up to 32 alphanumeric characters. Any displays defined or implied by this document are intended solely for use in the DABS test and evaluation program, and are not necessarily representive of recommended or require display devices for an operational DABS system.
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Summary

Formats and protocols are described for tactical ATC displays to be driven by the Standard Message interface of a DABS transponder and capable of handling a succession of data transmissions, each of which is individually acknowledged via a transponder reply before the transmission of the succeeding segment. Specific codes are...

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Provisional message formats and protocols for the DABS 32-character alphanumeric display

Improved satellite constellations for CONUS ATC coverage

May 1, 1974
  |
Project Report
Author:
Harry B. Lee
…
Published in:
MIT Lincoln Laboratory Report ATC-23
Topic:
air traffic control
R&D area:
R&D group:

Summary

This report examines the problem of designing a constellation of orbiting satellites capable of supporting an aircraft navigation/surveillance service over CONUS. It is assumed that the aircraft positions are determined by hyperbolic multilateration using all satellites visible at elevation angles exceeding a minimum angle. Comprehensive analyses are presented of three "baseline" constellations. The constellations are representative of previous large, medium, and small constellations. The analyses include calculation of The Geometric Dilution of Precision (GDOP) during level flight, calculation of GDOP after a key satellite is deleted, and calculation of GDOP during aircraft banking. Comparison of the resulting GDOP's with the theoretical minimum values indicates that there is considerable room for improvement. A new method of calculating GDOP is described. The method suggests that improved GDOP's can be obtained by placing satellites in retrograde orbits rather than the previous posigrade orbits. Accordingly, nine new constellations are designed that employ retrograde orbits. When subjected to the same analyses as the baseline constellations, the new constellations exhibit significantly improved GDOP's.
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Summary

This report examines the problem of designing a constellation of orbiting satellites capable of supporting an aircraft navigation/surveillance service over CONUS. It is assumed that the aircraft positions are determined by hyperbolic multilateration using all satellites visible at elevation angles exceeding a minimum angle. Comprehensive analyses are presented of three...

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Improved satellite constellations for CONUS ATC coverage

Provisional Signal Formats for the Discrete Address Beacon System, Revision I

April 25, 1974
  |
Project Report
Author:
Paul R. Drouilhet Jr
Published in:
MIT Lincoln Laboratory Report ATC-30,REV.1
Topic:
surveillance
R&D area:
R&D group:

Summary

This document specified provisional DABS signal formats, i.e., the characteristics of the "signals-in-space" which form the DABS interrogations and replies. Also included is a discussion of the utilization of the described formats to effect the surveillance and data link communication functions for which DABS has been designed. These signal formats will be used in the design and construction of engineering development model transponders and interrogators for prototype system test and evaluation at NAFEC during Phase II of the DABS Development Program; and, with modifications resulting from this test and evaluation effort, will form the basis for the operational implementation of DABS.
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Summary

This document specified provisional DABS signal formats, i.e., the characteristics of the "signals-in-space" which form the DABS interrogations and replies. Also included is a discussion of the utilization of the described formats to effect the surveillance and data link communication functions for which DABS has been designed. These signal formats...

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Provisional Signal Formats for the Discrete Address Beacon System, Revision I

Provisional data link interface standard for the DABS transponder

April 25, 1974
  |
Project Report
Author:
George V. Colby
…
Published in:
MIT Lincoln Laboratory Report ATC-34
Topic:
surveillance
R&D area:
R&D group:

Summary

This document specifies provisional data link interface standards for the DABS transponder. It describes the function, timing, and electrical properties of the signals flowing to and from both the Standard Message Interface and the Extended Length Message Interface.
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Summary

This document specifies provisional data link interface standards for the DABS transponder. It describes the function, timing, and electrical properties of the signals flowing to and from both the Standard Message Interface and the Extended Length Message Interface.

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Provisional data link interface standard for the DABS transponder

Provisional message formats for the DABS/NAS interface

April 25, 1974
  |
Project Report
Author:
David Reiner
…
Published in:
MIT Lincoln Laboratory Report ATC-33
Topic:
surveillance
R&D area:
R&D group:

Summary

This document defines formats for messages which are to be transmitted between DABS and NAS facilities (en route or terminal). These messages include one-way Surveillance Reports to NAS and two-way Communications Messages. The latter support data link functions between NAS and DABS equipped aircraft, as well as aiding in the monitoring and control of DABS sensors. These message formats will be used in the design and construction of interface equipment and ground data links for prototype system test and evaluation at NAFEC during Phase II of the DABS Development Program; and, with modifications resulting from this test and evaluation effort, will form the basis for the operational implementation of DABS.
READ LESS

Summary

This document defines formats for messages which are to be transmitted between DABS and NAS facilities (en route or terminal). These messages include one-way Surveillance Reports to NAS and two-way Communications Messages. The latter support data link functions between NAS and DABS equipped aircraft, as well as aiding in the...

READ MORE
Provisional message formats for the DABS/NAS interface
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