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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.
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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

False target elimination at Albuquerque using ARTS-III software

March 12, 1974
  |
Technical Report
Author:
Alan G. Cameron
Published in:
MIT Lincoln Laboratory Report TN-1974-12
Topic:
air traffic control
R&D area:
R&D group:

Summary

Lincoln Laboratory has been assisting the U.S. Air Force Weapons Laboratory in the study of ATCRBS false targets caused by reflections from buildings at Albuquerque International Airport/Kirtland AFB. This paper discusses the false target situation there and proposes two algorithms for correcting it in ARTS-III software. The simpler of the two appears applicable to the Albuquerque situation today, and is easily extendable to correct false targets caused by new buildings. Since the process appears directly applicable to many FAA Secondary Radar installations, a more complex algorithm is also presented, which is suitable for use in very high density terminal areas.
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Summary

Lincoln Laboratory has been assisting the U.S. Air Force Weapons Laboratory in the study of ATCRBS false targets caused by reflections from buildings at Albuquerque International Airport/Kirtland AFB. This paper discusses the false target situation there and proposes two algorithms for correcting it in ARTS-III software. The simpler of the...

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False target elimination at Albuquerque using ARTS-III software

Bistatic scatter from rain

March 1, 1974
  |
Journal Article
Author:
Robert K. Crane
Published in:
IEEE Trans. Antennas Propag., Vol. 22, No. 2, March 1974, pp. 312-320.
Topic:
aviation weather
R&D area:
R&D group:

Summary

An experimental investigation of bistatic scatter from rain was conducted using a 143 km scatter path at frequencies of 4.5 and 7.7 GHz. The ratio of transmitted to received power (transmission loss) was measured for scattering angles ranging from6\degto130\deg. Simultaneous weather radar observations were made at a frequency of 1.3 GHz. Transmission loss estimates for the bistatic scatter path were computed using the weather radar data, the bistatic radar equation, and a model for the scattering cross section per unit volume of rain based upon Rayleigh scattering by an ensemble of water spheres. The measured and estimated transmission loss values were compared to test the use of the scattering model for the estimation of interference. The averaged ratio of measured-to-calculated transmission loss for the 4.5 GHz data is 1.2\pm 0.4dB. The averaged ratio for the 7.7 GHz data is -1.6\pm 0.5dB. Both these values are within the combined calibration uncertainties of each measurement system. The results show that the use of the simplified Rayleigh scattering cross section model for an ensemble of water spheres adequately describes bistatic scatter for a wide range of scattering angles and frequencies below 7.7 GHz for the hydrometeor types (rain, snow, and mixed rain and snow) encountered in New England.
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Summary

An experimental investigation of bistatic scatter from rain was conducted using a 143 km scatter path at frequencies of 4.5 and 7.7 GHz. The ratio of transmitted to received power (transmission loss) was measured for scattering angles ranging from6\degto130\deg. Simultaneous weather radar observations were made at a frequency of 1.3...

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Bistatic scatter from rain

The rain range experiment -- propagation through a simulated rain environment

March 1, 1974
  |
Journal Article
Author:
Robert K. Crane
…
Published in:
IEEE Trans. Antennas and Propagation, Vol. 22, No. 2, March 1974, pp. 321-328.
Topic:
weather
R&D area:
R&D group:

Summary

The rain range experiment was conducted to test the adequacy of the assumptions usually made in the analysis of attenuation or phase shift due to rain: spherical drop shape, Mie scattering for a single drop, and single scattering theory for the coherent summation of the effects of each drop. A sprayer system was built that provided a stable drop size distribution that was measured and used for the estimation of the attenuation and phase shift on a line-of-sight measurement path through the spray. Measurements of attenuation and phase shift were made using vertical and horizontal polarization at 7.9 GHz and vertical polarization at 33.9 GHz. The results of the experiment show agreement between measurements and the theoretical model. The 7.9 GHz data also showed the attenuation and phase shift for horizontal polarization to be higher than for vertical polarization.
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Summary

The rain range experiment was conducted to test the adequacy of the assumptions usually made in the analysis of attenuation or phase shift due to rain: spherical drop shape, Mie scattering for a single drop, and single scattering theory for the coherent summation of the effects of each drop. A...

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The rain range experiment -- propagation through a simulated rain environment

A summary of the DABS transponder design/cost studies

March 1, 1974
  |
Project Report
Author:
Thomas J. Goblick
…
Published in:
MIT Lincoln Laboratory Report ATC-27
Topic:
surveillance
R&D area:
R&D group:

Summary

One of the major concerns in the DABS development program has been the cost of the DABS transponder. In order to realistically assess the impact on transponder cost of the many alternative techniques and design choices being considered for DABS, four study contracts were awarded to avionics manufacturers to design and estimate costs of special circuitry (in Phase I) and complete transponders (in Phase II). This report summarizes the major results of these design/cost studies, which cover general aviation, military, and air carrier transponder designs (including a retrofit kit for the military APX-72 transponder). The transponder design/cost studies have had a marked influence on the design of the DABS signal and message formats. Since the cost studies were basically intended for comparing link options for DADS, the transponder specifications used in these cost studies do not correspond in detail to current DABS transponder specifications. Therefore the cost data contained in this report cannot be taken to be completely representative of the cost of the finally specified DABS transponders.
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Summary

One of the major concerns in the DABS development program has been the cost of the DABS transponder. In order to realistically assess the impact on transponder cost of the many alternative techniques and design choices being considered for DABS, four study contracts were awarded to avionics manufacturers to design...

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A summary of the DABS transponder design/cost studies

Technical Assessment of Satellites for CONUS Air Traffic Control, Volume II - Random Access Aircraft-To-Satellite Techniques

February 28, 1974
  |
Project Report
Author:
Kenneth S. Schneider
…
Published in:
MIT Lincoln Laboratory Report ATC-26,II
Topic:
air traffic control
R&D area:
R&D group:

Summary

A number of satellite system techniques have been suggested as candidates to provide ATC surveillance, communication, and/or navigation service over CONUS. All techniques perform postion determination by multilateration using a constellation of satellites. They can be categorized as follows: 1) Coordinated Aircraft-to-Satellite Techniques (CAST), 2) Random Access Aircraft-to-Satellite Techniques (RAST), and 3) Satellite-to-Aircraft Techniques (SAT). A technical assessment is made of the various techniques with no one particular technique emerging as superior; several feasible alternatives are identified. The assessment indicates that satellite bases techniques for CONUS ATC can be developed without relying on high risk technology. This volume deals with RAST, CAST and SAT are treated in companion volumes. A system employing RAST could operate by having each aircraft transmit a unique signature periodically, without any coordination of transmissions. The position of the aircraft is then obtained by multilateration using the arrival times of its signature at four or more satellites. Since aircraft transmissions are not coordinated, there is the possibility that different signatures may overlap at a satellite receiver. The resulting mutual interference is a factor in the performance of systems employing RAST. The critical technical aspects of RAST are explored with special emphasis on signaling formats, satellite coverage issues, degradation due to mutual interference and susceptibility to jamming.
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Summary

A number of satellite system techniques have been suggested as candidates to provide ATC surveillance, communication, and/or navigation service over CONUS. All techniques perform postion determination by multilateration using a constellation of satellites. They can be categorized as follows: 1) Coordinated Aircraft-to-Satellite Techniques (CAST), 2) Random Access Aircraft-to-Satellite Techniques (RAST)...

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Technical Assessment of Satellites for CONUS Air Traffic Control, Volume II - Random Access Aircraft-To-Satellite Techniques

Summary of results of antenna design cost studies

February 19, 1974
  |
Project Report
Author:
Jean-Claude Sureau
Published in:
MIT Lincoln Laboratory Report ATC-22
Topic:
antennas
R&D area:
R&D group:

Summary

Design/cost studies on antenna systems for DABS have been carried out by Texas Instruments and Westinghouse under Lincoln Laboratory sponsorship. For independent, mechanically-rotating systems aperture widths between 10' and 35' and heights between 4' and 16' were considered, with estimated corresponding production costs ranging from $10K to more than $200K. No generally-recommended implementation emerged although the trend was to choose planar arrays for stringent performance requirements and to accept less expensive reflectors when requirements were sufficiently relaxed. Although the aperture size was found to have a significant cost impact on the remainder of the system (pedestal, drive, tower), the antenna usually accounted for less than half of the total antenna installation cost. With the use of off-boresight monopulse direction-finding, agile beam arrays require only slightly more than one beam position per beamwidth. Even with the resulting simplification in the beamforming circuitry, their cost is about twice that of comparable rotators and starts at about $200K. DABS systems which share the same pedestal as primary radars ("co-located") are inherently highly constrained and tend to lead to unique implementations. For an ASR installation, an integral monopulse beacon feed constitutes an economical (less than $5K) and expedient implementation with performance parameters which, though not optimum, are acceptable for DABS (4 degrees beamwidth and 2 dB/degree elevation cut-off rate). A back-mounted antenna of the same (or smaller) aperture size as the AST reflector can also be implemented as a retrofit for about $40K. For ARSR installations, integral monopulse beacon feeds are also feasible at a very nominal cost but some performance compromises have to be accepted. Back-mounted DABS antennas can be accommodated in a large range of aperture sizes.
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Summary

Design/cost studies on antenna systems for DABS have been carried out by Texas Instruments and Westinghouse under Lincoln Laboratory sponsorship. For independent, mechanically-rotating systems aperture widths between 10' and 35' and heights between 4' and 16' were considered, with estimated corresponding production costs ranging from $10K to more than $200K...

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Summary of results of antenna design cost studies

Technical Assessment of Satellites for CONUS Air Traffic Control, Volume III - Satellite-To-Aircraft Techniques

February 19, 1974
  |
Project Report
Author:
Harry B. Lee
…
Published in:
MIT Lincoln Laboratory Report ATC-26,III
Topic:
air traffic control
R&D area:
R&D group:

Summary

A number of satellite system techniques have been suggested as candidates to provide ATC surveillance, communication, and/or navigation service over CONUS. All techniques perform postion determination by multilateration using a constellation of satellites. They can be categorized as follows: 1) Coordinated Aircraft-to-Satellite Techniques (CAST), 2) Random Access Aircraft-to-Satellite Techniques (RAST), and 3) Satellite-to-Aircraft Techniques (SAT). A technical assessment is made of the various techniques with no one particular technique emerging as superior; several feasible alternatives are identified. The assessment indicates that satellite bases techniques for CONUS ATC can be developed without relying on high risk technology. This three-volume report is a technical assessment of all three techniques. The present volume examines satellite-to-aircraft techniques (SAT). The remaining two volumes treat CAST and RAST. The assessment has shown that workable systems could be configured using any one of the three techniques without reliance on high risk technology. No one technique has emerged as superior. Rather several viable alternatives have been identified. All techniques appear to require more costly avionics than today's ground-based system.
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Summary

A number of satellite system techniques have been suggested as candidates to provide ATC surveillance, communication, and/or navigation service over CONUS. All techniques perform postion determination by multilateration using a constellation of satellites. They can be categorized as follows: 1) Coordinated Aircraft-to-Satellite Techniques (CAST), 2) Random Access Aircraft-to-Satellite Techniques (RAST)...

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Technical Assessment of Satellites for CONUS Air Traffic Control, Volume III - Satellite-To-Aircraft Techniques
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