Spectra of radio refractive index between ground level and 5000 feet above ground

Straiton, A. W.; Deam, A. P.; Walker, Gordon J.

doi:10.1109/tap.1962.1137935

Cited by 4 publications

(5 citation statements)

References 7 publications

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“…However, it also appears that the value for (13fV2)/l which they used (taken to be 7 X I0-16 ft-1 ) is too small to represent typical atmospheric conditions near the earth's surface. From the results of fairly extensive refractivity measurements made at the University of Texas [Straiton et al, 1962], we find that values of (13N2) vary over a ratio of 1()6 and that l can vary from approximately 20 m up to the order of 1 km. In using measured values of (8N2) it is important to remember that the measured values may give a result smaller than the true value, if the distance (or equivalent time interval) over which the measurement is taken is not large compared with the correlation distance.…”

Section: Comparison With Theorymentioning

confidence: 93%

“…The effect of anisotropy in the refractive-index structure would make the effects of beam-angle scintillation even more severe in the vertical than in the horizontal direction. Such anisotropy is likely near the earth's surface, in view of the marked increase in meansquared refractive-index values measured [Straiton et al, 1962] in the first 200ft above ground over values measured at hundreds or thousands of feet of altitude. Thus it is not unusual for the angle-of-arrival pattern in the vertical plane to fluctuate over an angular extent of approximately 1° or more.…”

Section: Vertical Angle-of-arrival Patternsmentioning

confidence: 99%

“…This was not done because refractometers were not available to the experimenters; however, comparisons have been made between theory and experiment using representative values of mean-squared refractivity and of correlation distance as measured at Austin, Tex. [Straiton et al, 1962].…”

Section: Introductionmentioning

confidence: 99%

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Angle‐of‐Arrival Measurements Performed Over a 296‐km Troposcatter Path

Kieburtz

Fantera

1966

Radio Science

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Angle‐of‐arrival measurements have been performed on a troposcatter path by simultaneous reception in angle diversity using antenna beams of 19.2‐min beamwidth. The transmitting beamwidth is also 19.2 min, permitting measurement of the beam broadening due to the variable refractive index along the propagation path. The results of these measurements have indicated that the antenna beam may sometimes undergo an rms horizontal deflection as great as 17 min of arc over the half‐path length of 148 km.

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Section: Comparison With Theorymentioning

confidence: 93%

Section: Vertical Angle-of-arrival Patternsmentioning

confidence: 99%

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Angle‐of‐Arrival Measurements Performed Over a 296‐km Troposcatter Path

Kieburtz

Fantera

1966

Radio Science

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“…As pointed out by Straiton, Deam, and Walker (1962), the atmospheric refractive-index variations do not have the properties of a statistically stationary process. In general, the longer the data sample used, the greater will be the rms value of the variations and the higher will be the correlation coefficient between the variations at two points.…”

Section: Introductionmentioning

confidence: 99%

“…For these reasons, there are certain advantages in studying the results of refractive-index difference tests. Several groups have made such measurements; for example, see Straiton, Deam, and Walker (1962) and Lane (1964).…”

Section: Introductionmentioning

confidence: 99%

Analysis of Spectra of Atmospheric Refractive Index Differences

et al. 1968

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When atmospheric refractive index is observed by measuring the index differences between two points, a filtering action is introduced in the fluctuation spectra. A filter function is obtained when the refractive index difference spectra frequency component is divided by the corresponding frequency component of the index spectra for a single‐point data. Test results of this filter function are compared with theoretical models. The measured filter functions for 12 data samples obtained with four refractometers on top of an 85‐m tower, are presented. These 12 cases are arranged in the order of increasing wind variability; that is, of increasing ratio of rms wind‐speed variation to the mean‐wind speed. The measured data are compared with theoretical filter functions derived assuming a “frozen‐atmosphere” model; a statistically homogeneous and isotropic invariant structure being assumed to be carried along at the mean‐wind velocity. A single mean‐wind velocity is assumed for those periods for which the measured wind data indicate a nearly constant flow. For more variable situations an integration over a range of mean‐wind speeds and wind directions is performed. Though there are numerous marked differences between the measured and calculated filter functions (as would be expected whenever a crude model is used to predict results for a truly complex situation), the model assumed does provide satisfactory explanations for many of the observed features. An unexplained anomaly, which appears in the measured filter function for many of the cases, is that at the high‐frequency end, the functions are lower than predicted.

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Evidence of anisotropy in tropospheric microstructure

Bolgiano¹

1963

J. Geophys. Res.

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Spectra of radio refractive index between ground level and 5000 feet above ground

Cited by 4 publications

References 7 publications

Angle‐of‐Arrival Measurements Performed Over a 296‐km Troposcatter Path

Angle‐of‐Arrival Measurements Performed Over a 296‐km Troposcatter Path

Analysis of Spectra of Atmospheric Refractive Index Differences

Evidence of anisotropy in tropospheric microstructure

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