By Topic

Proceedings of the IEEE

Issue 4 • April 1969

Filter Results

Displaying Results 1 - 25 of 76
  • [Front cover and table of contents]

    Publication Year: 1969, Page(s): c1
    Request permission for commercial reuse | PDF file iconPDF (1433 KB)
    Freely Available from IEEE
  • Scanning the issue

    Publication Year: 1969, Page(s):371 - 374
    Cited by:  Papers (3)
    Request permission for commercial reuse | PDF file iconPDF (400 KB)
    Freely Available from IEEE
  • Weak scattering in random media, with applications to remote probing

    Publication Year: 1969, Page(s):375 - 406
    Cited by:  Papers (108)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2526 KB)

    A simple phase-screen technique has been used to derive statistical characterizations of the perturbations imposed upon a wave (plane, spherical, or beamed) propagating through a random medium. The method is essentially physical rather than mathematical; its application is limited only by the weak-scattering approximation, a limitation which is important only for long optical or acoustical paths. ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Fluctuations of a focused beam wave for atmospheric turbulence probing

    Publication Year: 1969, Page(s):407 - 414
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (619 KB)

    This paper demonstrates that a focused beam wave may be effectively used to probe the atmospheric turbulence. Unlike plane and spherical waves, the focused beam has two parameters, i.e., the beam size and the radius of curvature of phase front at the aperture which may be easily varied experimentally. General formulations for the amplitude and phase correlation functions and structure functions of... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Remote probing of the optical strength of atmospheric turbulence and of wind velocity

    Publication Year: 1969, Page(s):415 - 420
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (691 KB)

    A procedure for determining the optical strength of turbulence of the atmosphere and the wind velocity at various altitudes by measuring the spatial and temporal covariance of scintillation is developed. Emphasis is placed on the development of the formal relationships that have to be inverted to obtain the desired results. For determination of optical strength of turbulence, it is a linear integr... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Electromagnetic scatter from small dielectric gradients in a continuous medium

    Publication Year: 1969, Page(s):421 - 427
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (801 KB)

    A new approach is presented to the formulation and understanding of the problem of electromagnetic scatter from a slightly perturbed continuous medium. The problem is expressed in terms of periodic functions instead of conventional power series. From this formulation, specular properties are observed that are not obtainable from older considerations. The approach was verified with a laboratory exp... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Passive remote sensing at microwave wavelengths

    Publication Year: 1969, Page(s):427 - 439
    Cited by:  Papers (46)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1408 KB)

    Passive remote sensing at microwave frequencies has applications which range from meteorology to oceanography and geology. The meteorological applications are the most fully developed and include measurements of the temperature profile of the atmosphere and of the atmospheric distribution of H2O and O3. Such measurements can he made from space or from the ground by utilizing ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The influence of clouds on microwave brightness temperatures viewing downward over open seas

    Publication Year: 1969, Page(s):440 - 446
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1727 KB)

    Microwave brightness temperatures for the case of downward viewing from above the earth's atmosphere over water for the 1- to 2-cm wavelength range are calculated for comparison with observations. A model of the troposphere which contains homogeneous layer clouds of varied thickness and liquid water content is used to compute estimates of the influence which clouds would have on real observations.... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A multiwavelength line-of-sight experiment for remote atmospheric sensing

    Publication Year: 1969, Page(s):446 - 458
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1271 KB)

    Simultaneous measurements have been made on a 3.57- km line-of-sight atmospheric path using a phase quadrature technique at 10.4 GHz, plus a combination of near-infrared and 23.8-GHz transmissometers operating in oxygen and water vapor absorption bands, respectively. The latter two systems provide the separate dry and wet terms of integrated radio refractivity for use in interpretation of the 10.4... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Sensing the earth's atmosphere with occultation satellites

    Publication Year: 1969, Page(s):458 - 467
    Cited by:  Papers (17)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (948 KB)

    A pair of satellites in the same earth orbit but separated by about 60° in phase will have a radio path between them that intersects the atmosphere continuously. With a coherent transponder between satellites at a frequency of 5 GHz, changes of 3 cm in the phase path can be recorded, giving a sensitivity to changes in atmospheric density of 1:18 000. With a set of six satellites to sense dens... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Probing the clear atmosphere with high power, high resolution radars

    Publication Year: 1969, Page(s):468 - 480
    Cited by:  Papers (43)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (4046 KB)

    Observations of radar echoes from the clear atmosphere are presented and the scattering mechanisms responsible for the two basic types of clear-air echoes are discussed. The commonly observed dot echo originates from a point in space and usually shows little variation in echo intensity over periods of about 0.1 second. The results of the most recent investigations of these clear-air dot targets ar... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Some current developments in radio systems for sounding ionospheric structure and motions

    Publication Year: 1969, Page(s):481 - 486
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1133 KB)

    Two new developments in radio pulse sounding of the ionosphere are described with emphasis on some advantages available from modern digital techniques. The current stage of development of a digital ionosonde (dynasonde) is illustrated, showing the effectiveness of a simple logical process for distinguishing echoes from noise. Another digital radio-sounding system, including instrumentation (the ki... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Remote sensing of the terrestrial environment with an HF radio high-resolution azimuth and elevation scan system

    Publication Year: 1969, Page(s):487 - 493
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2045 KB)

    High-resolution arrays, steerable over a sector in azimuth and elevation, can be used to sense the state of the remote ionosphere and possibly certain characteristics of the sea surface. Direction-of-arrival measurements of one-way signals or backscatter techniques can sense the presence of traveling ionospheric disturbances and determine some of their parameters. Backscatter data can provide info... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Radio wave reflections from large horizontal gradients in the topside ionosphere

    Publication Year: 1969, Page(s):493 - 496
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (602 KB)

    Radio wave echoes due to total reflection from the edge of large-scale depressions of electron density are observed by topside sounding satellites. The resulting traces on swept-frequency ionograms have a minimum frequency which is the nose of a loop-shaped trace. The nose frequency and the shape of the traces depend upon the distribution of electron density in the depression and the location of t... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Theory and practice of ionosphere study by Thomson scatter radar

    Publication Year: 1969, Page(s):496 - 530
    Cited by:  Papers (249)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (4435 KB)

    The application of Thomson (or incoherent) Scatter observations to the study of the earth's ionosphere is described. Those aspects of theory of Thomson Scatter that have been put to practical use in ionospheric investigations are reviewed briefly and the type of radar equipment constructed for these investigations is discussed. Methods of measuring electron density, electron and ion temperatures, ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optical doppler measurement of microscale wind velocity

    Publication Year: 1969, Page(s):530 - 536
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (811 KB)

    A system analysis of the feasibility of optical heterodyne measurement of Doppler shifts as a method for the remote determination of vector wind velocity is carried out. It is found that with a 50-mW laser at 6328 Å, naturally occurring aerosols in clear air will permit measurements at distances of only a few tens of centimeters; but haze and dust will extend this range to a few tens of meter... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Indirect atmospheric measurements utilizing rake tropospheric scatter techniques—Part I: The rake tropospheric scatter technique

    Publication Year: 1969, Page(s):537 - 551
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1258 KB)

    Unusually detailed multipath resolution of the tropospheric-scatter medium has been obtained by incorporating Rake instrumentation into tropospheric transhorizon microwave experiments. Radio-frequency carriers at approximately 900 MHz, each binary phase-shift keyed at 10 megabauds by a pseudorandom sequence of digits and subsequently filtered to a 10-MHz bandwidth, were transmitted during separate... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Indirect atmospheric measurements utilizing rake tropospheric scatter techniques—Part II: radiometeorological interpretation of rake channel-sounding observations

    Publication Year: 1969, Page(s):552 - 559
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (795 KB)

    Successful remote sensing of the lower atmosphere's refractive-structure has been demonstrated using the Rake tropospheric scatter channel-sounding technique. The detected atmospheric structures show spatial refractive inhomogeneity in the form of discrete scattering layers at different heights. Detected layer heights and crosspath wind speeds were found to be in close agreement with U. S. Weather... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Multisensor detection of ionospheric phenomena

    Publication Year: 1969, Page(s):559 - 571
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1999 KB)

    For the past several years, observations using a large number of geophysical sensors have been conducted at a site near Boulder, Colo. Data are continuously recorded on magnetic tape and have the advantages of a common time base and the availability of an on-line computer which performs data processing and controls the operation of the station. The original purpose of the installation was to study... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Acoustic methods for the remote probing of the lower atmosphere

    Publication Year: 1969, Page(s):571 - 578
    Cited by:  Papers (78)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (932 KB)

    The potential usefulness of acoustic methods for the remote probing of the lower atmosphere is reviewed. Starting with a comparison of the effects of temperature, wind, and humidity fluctuations upon the refractive index of air to electromagnetic and acoustic waves, it is shown that the fluctuations in acoustic refractive index may be expected to be about 1000 times stronger than in the radio case... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Acoustic sounding—A new approach to the study of atmospheric structure

    Publication Year: 1969, Page(s):579 - 587
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2797 KB)

    Short pulses of acoustic energy at a carrier frequency of 950 Hz were beamed upwards from an array of loudspeakers. The energy which was backscattered from the random fluctuations of temperature within the turbulent regions of the lower 300 meters of the atmosphere was received on the same array and recorded on a facsimile receiver. The acoustic echoes were calibrated against temperature and wind ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The radar radiometer

    Publication Year: 1969, Page(s):587 - 590
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (446 KB)

    Addition of a radar to a scanning microwave radiometer is shown to be simple and to consume little power. Since both the radar and the radiometer receive signals having the statistical properties of noise, both receivers may use the Dicke synchronous detection system, provided the radar receives enough independent samples. Application of the combined instrument to spacecraft measurement both of oc... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Panchromatic and polypanchromatic radar

    Publication Year: 1969, Page(s):590 - 593
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (561 KB)

    Application of broad-band (panchromatic) illumination in radar systems should permit improvement in image quality and reduction of tracking and detection problems due to fading. The effect of frequency averaging on radar return from a simple target array is demonstrated by numerical computation and on image quality by ultrasonic simulation. The required bandwidth for a slightly rough random surfac... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Some aspects of remote sensing as applied to oceanography

    Publication Year: 1969, Page(s):594 - 604
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (4164 KB)

    Limitations in the state-of-the-art of remote sensing instrumentation and restriction of experimental ground truth, imposed by the inaccessibility of the oceanographic environment, have inhibited the application of remote sensing techniques to oceanographic research and the implementation of operational environmental monitoring programs. However, preliminary experiments are demonstrating the appli... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Arctic ice type identification by radar

    Publication Year: 1969, Page(s):605 - 611
    Cited by:  Papers (20)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1486 KB)

    The pack ice in the Arctic Ocean was the subject of a special remote sensing mission conducted jointly by the National Aeronautics and Space Administration, the Navy Oceanographic Office, the U. S. Army Cold Regions Research and Engineering Laboratory, the Arctic Institute of North America, and the University of Kansas. One of the most significant results of the experiment was verification of the ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

Aims & Scope

The most highly-cited general interest journal in electrical engineering and computer science, the Proceedings is the best way to stay informed on an exemplary range of topics.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
H. Joel Trussell
North Carolina State University