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Interim report transponder test program

Published in:
Project Report ATC-5, MIT Lincoln Laboratory

Summary

This report covers the work done under the first phase of a continuing program of field tests on ATCRBS transponders. Characteristic transponder parameters were measured to determine their degree of compliance with the current specifications. A mobile van was outfitted with electronic test equipment which simulated the transmitter and receiver sections of a ground interrogator and allowed measurement of transponder parameters. A horn antenna located near the aircraft under test was used to couple signals to and from the transponder. The tests were performed at nine civilian airports on transponders installed in operational general aviation aircraft. The results of the measurements on the first 96 units are reported in detail and tentative conclusions drawn.
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Summary

This report covers the work done under the first phase of a continuing program of field tests on ATCRBS transponders. Characteristic transponder parameters were measured to determine their degree of compliance with the current specifications. A mobile van was outfitted with electronic test equipment which simulated the transmitter and receiver...

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Technical development plan for a discrete address beacon system, vol. II [draft]

Author:
Published in:
MIT Lincoln Laboratory Report ATC-4-II

Summary

The Technical Development Plan for a Discrete Address Beacon System is published in two volumes. Volume I is the basic plan, while this volume (Volume II) contains a more detailed description of the 46 tasks recommended for accomplishment during Phase 1 of the development cycle. It also includes cost estimates for each task.
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Summary

The Technical Development Plan for a Discrete Address Beacon System is published in two volumes. Volume I is the basic plan, while this volume (Volume II) contains a more detailed description of the 46 tasks recommended for accomplishment during Phase 1 of the development cycle. It also includes cost estimates...

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Technical development plan for a discrete address beacon system, vol. I [draft]

Author:
Published in:
MIT Lincoln Laboratory Report ATC-4-I

Summary

The requirement for a Discrete Address Beacon System (DABS) was highlighted by the Department of Transportation Air Traffic Control Advisory Committee to provide improved surveillance and ground-air communications in support of air traffic control automation. This document presents a technical development plan for such a system; this plan was developed in close colaboration with FAA personnel in the Office of System Engineering Management and the Systems Research and Development Service. The DABS Technical Development Plan identifies the critical issues and technical options, presents a program for their resolution, followed by the development and test of a feasibility model of the system, and suggests a management structure to coordinate and carry out the many tasks involved in the implementation of the plan.
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Summary

The requirement for a Discrete Address Beacon System (DABS) was highlighted by the Department of Transportation Air Traffic Control Advisory Committee to provide improved surveillance and ground-air communications in support of air traffic control automation. This document presents a technical development plan for such a system; this plan was developed...

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Radar meteorological applications of automatic film reading

Author:
Published in:
Opt. Eng., Vol. 9, No. 2, January 1971, 090246.

Summary

The data recording of storm information as detected by a weather radar has been customarily made on photographic film. Research radars and an occasional U. S. Weather Bureau radar are fitted with scope cameras to record the radar plan position indicator (PPI) display. Over the past 15 years a large sample of weather radar data has been accumulated in this fashion. The photographic technique provides an easy, quick, and inexpensive way to record weather radar data. The major drawback of this technique is data reduction. Information on storm shape, size, and intensity is normally extracted from the photographic images by hand. This means that only the most interesting aspects of individual storms are analyzed and the vast majority of the collected radar data is not analyzed. A vast amount of climatological information could be obtained from the existing store of weather radar data if an automatic technique of data retrieval were available. The first part of this report describes the use of a computer-controlled programmable film reader to process weather radar PPI photographs to obtain digital maps of rainfall intensity for use in climatological studies.
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Summary

The data recording of storm information as detected by a weather radar has been customarily made on photographic film. Research radars and an occasional U. S. Weather Bureau radar are fitted with scope cameras to record the radar plan position indicator (PPI) display. Over the past 15 years a large...

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Measurement of clear air turbulence in the lower stratosphere using the Millstone Hill L-Band Radar

Author:
Published in:
14th Conf. on Radar Meteorology, 17-20 November 1970, pp. 101-106.

Summary

Radar measurements of thin turbulent layers in the clear atmosphere have been extensively reported in the literature and have recently been summarized by Hardy and Katz (1969). The majority of the thin turbulent layer detections reported have been for layers in the lower troposphere. Using the high power radar facilities at Wallops Island, Atlas, et al (1966) have detected layers at heights up to the tropopause. In this paper, layer detections at heights above the tropopause are discussed. The detection of layers in the lower 10 km of the stratosphere is made possible by using a radar system which has approximately 10 dB more sensitivity than the Wallops Island radars for the detection of turbulent layers. The program of radar measurements of thin turbulent layers was undertaken to provide basic information about the structure of scattering layers in the upper troposphere and lower stratosphere for use in the prediction of troposcatter field strengths. The radar measurements were accompanied by radiosonde soundings. For a limited series of measurements, a U-2 aircraft was also used to probe for turbulent layers.
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Summary

Radar measurements of thin turbulent layers in the clear atmosphere have been extensively reported in the literature and have recently been summarized by Hardy and Katz (1969). The majority of the thin turbulent layer detections reported have been for layers in the lower troposphere. Using the high power radar facilities...

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Monostatic and bistatic scattering from thin turbulent layers in the atmosphere

Author:
Published in:
MIT Lincoln Laboratory Report TN-1968-34

Summary

Measurements were made of the scattering properties of thin turbulent layers at and above the tropopause. The Millstone Hill L-band radar was used to measure the backscatter cross section per unit volume of these layers as a function of time and space. An X-band forward scatter link was set up between Wallops Island, Virginia and Westford, Massachusetts to observe scattering from these layers. Although the radar could not provide observations of the common volume of the forward scatter link, for days where no clouds were observed in the vicinity of the tropopause, the radar observations of layers near the tropopause showed horizontal uniformity of height and backscatter cross section, and the radiosonde data taken near the radar and near the common volume showed similar wind and temperature structure near the tropopause, the signal strength on the forward scatter link and its dependence on scattering angle behaved in accordance with the prediction of turbulent scattering theory using the radar data as an input. The radar observations have shown that on each day measurements were made, layers were detected near and above the tropopause. Turbulent layers in the stratosphere have been detected at heights up to 22 km. These layers provide one of the mechanisms for weak, long-distance troposcatter propagation.
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Summary

Measurements were made of the scattering properties of thin turbulent layers at and above the tropopause. The Millstone Hill L-band radar was used to measure the backscatter cross section per unit volume of these layers as a function of time and space. An X-band forward scatter link was set up...

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Simultaneous radar and radiometer measurements of rain shower structure

Author:
Published in:
MIT Lincoln Laboratory Report TN-1968-33

Summary

Simultaneous measurements of the backscatter cross section per unit volume and the sky temperature were made for limited volumes of rain showers using an L-band radar and an X-band radiometer. The object of the measurements was to provide data to validate the method used to compute attenuation and sky temperature given weather radar data as an input and to investigate the spatial changes in rainfall intensity and in the attenuation cross section per unit volume. The sky temperature was calculated using the radiative transfer equation and the distribution of attenuation cross section per unit volume estimated from the weather radar data. An empirical relationship between attenuation and backscatter cross sections was used based upon the results of a large number of Mie theory computations using measured raindrop size distributions. The results of the comparisons between calculated and measured sky temperature show good agreement. The discrepancies between the measured and calculated values are due to the difference in the antenna beamwidths for the two systems (0.6° for the L-band radar, 0.07° for the X-band radiometer). From these discrepancies the spatial distances over which the attenuation cross section can change significantly can be estimated. The results show that for the rain showers investigated, the attenuation cross section per unit volume can change an order of magnitude in 400 meters and the integrated attenuation along a horizontal line-of-sight can change an order of magnitude for a 1. 5km horizontal translation of the path.
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Summary

Simultaneous measurements of the backscatter cross section per unit volume and the sky temperature were made for limited volumes of rain showers using an L-band radar and an X-band radiometer. The object of the measurements was to provide data to validate the method used to compute attenuation and sky temperature...

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Microwave scattering parameters for New England rain

Author:
Published in:
MIT Lincoln Laboratory Report TR-426

Summary

Scattergrams of attenuation coefficient, effective reflectivity factor, single-scattering albedo, and radio refractivity vs liquid-water content, rain rate, and reflectivity factor are presented for a raindrop temperature of 0.0 degrees celsius and frequencies of 1.29, 2.80, 8.0, 9.35, 15.5, 35.0, 70.0, and 94.0 GHz. The scattergrams were computed using Mie theory to compute the scattering parameters for single raindrops, and single-scattering theory to compute the integrated scattering effects of an ensemble of raindrops. Measured drop-size distributions were used to generate the scattergrams.
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Summary

Scattergrams of attenuation coefficient, effective reflectivity factor, single-scattering albedo, and radio refractivity vs liquid-water content, rain rate, and reflectivity factor are presented for a raindrop temperature of 0.0 degrees celsius and frequencies of 1.29, 2.80, 8.0, 9.35, 15.5, 35.0, 70.0, and 94.0 GHz. The scattergrams were computed using Mie theory...

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