An analysis of time variations in tropospheric refractive index and apparent radio path length

Thompson, M. C.; Janes, H. B.; Kirkpatrick, Allison

doi:10.1029/jz065i001p00193

Cited by 24 publications

(6 citation statements)

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“…Although the path had a low elevation angle, the measured spectral shapes are probably applicable to the transatmospheric path. A later series of measurements [16] investigated a longer (25 km), steeper path on the island of Maui, Hawaii, and were in good agreement with the Boulder measurements, except that the meansquare phase fluctuations were two orders of magnitude greater, apparently due to the longer path and the more humid climate.…”

Section: Contribution From the Second Error Termsupporting

confidence: 60%

“…The slower (perhaps less than 1 cycle per minute to 1 cycle per hour) phase variations apparently follow the refractivity variations, which seem to have an w-1 spectral dependence over the 1 cycle per year (Cy = 2 X 10-7) to 1 cycle per day (Cod = 7.3 X l0-4) interval [16]. Below 1 cycle per year, the spectral intensity seems to decrease rapidly.…”

Section: Contribution From the Second Error Termmentioning

confidence: 94%

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Preliminary Analysis of a Proposed High-Stability Frequency Standard Distribution System

Burns

1971

IEEE Trans. Aerosp. Electron. Syst.

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This paper presents the results of a preliminary analysis of a satellite-borne system for distributing a reference frequency over global distances with an accuracy and stability apparently at least as good as those of independent atomic standards. This system is designed to distribute an accurate time scale [1], which could be used for time keeping, but not for transmitting epoch information. Epoch synchronization via synchronous satellite has been accom-The most stable standards are the primary atomic frequency standards [31, [41, and these form the basis for some of the time scales in use [11, [51 . A stability of 1 part in 1014 for 30 minutes averaging time for a hydrogen maser has been reported [3]. To be worthwhile, any complex distribution system should be able to equal-if not surpassthis stability. AbstractA system for distributing a frequency reference, which involves the use of geostationary satellites and two-way microwave transmissions, seems capable of stabilities exceeding those of primary atomic standards. The principal sources of error are instabilities in oscillators in the system, imperfect geostationary orbits, additive noise, and radio propagation effects. Even extreme assumptions of propagation phase instability lead to very small errors. Thus the limitations on stability seem to be imposed by the hardware.

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Section: Contribution From the Second Error Termsupporting

confidence: 60%

Section: Contribution From the Second Error Termmentioning

confidence: 94%

Preliminary Analysis of a Proposed High-Stability Frequency Standard Distribution System

Burns

1971

IEEE Trans. Aerosp. Electron. Syst.

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“…The computing method used is essentially that suggested by Blackman and Tukey [1958]. This analysis has been described in detail previously [Thompson, Janes, and Kirkpatrick, I960;Thompson and Janes, 1959].…”

Section: Power Spectrum Analysismentioning

confidence: 99%

Radio path length stability of ground-to-ground microwave links

Thompson¹

1964

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conducted a series of eight field experiments in 1958 and 1959 to study the variation in the apparent path length of ground-toground microwave links (i. e. , the variations in phase of 9400 Mc/s signals) and the corresponding variations in radio refractive index and other atmospheric parameters measured at the path terminals. This report summarizes the results obtained on paths in Colorado and Florida. It also includes an analysis of long-term variations in the apparent path length and associated variables recorded during each experiment, and a power spectrum analysis of short-term variations in apparent path length and refractivity. 1. This work was sponsored, in part, by the U. S. Air Force Ballistic Missile Division under contract number AF 04(647)-134. purpose of the experiments was to study the statistical properties of the apparent path length variations and their dependence on various meteorological parameters. The method used for measuring the apparent path length fluctuations is basically a phase comparison technique which has been described previously [Thompson and Vetter, 1958]. The most impor-2 tant atmospheric parameter in this study is the radio refractivity , which was measured in two ways. The long-term variations were obtained from observations of temperature, pressure, and relative humidity. The short-term variations were recorded by the use of a microwave refractometer. Standard meteorological techniques were used to record atmospheric pressure, temperature, relative humidity, wind velocity, and (in some cases) incident solar radiation (insolation) at one or both path terminals. The first of the experiments (referred to hereafter as "runs") was made over a 15. 2 km path near Boulder, Colorado, during a 40 hour period in September 1958. A map and terrain profile of this path are shown in figures 1 and 2. The principal objectives were to study path length variations at 9400 Mc/s over a path having little or no ground reflection, using both horizontal and vertical polarization.

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“…A source of annoyance to the operators of sensitive radars is the unpredictable reflection of radar waves from these atmospheric irregularities (Plank 1956(Plank , 1959). Yet another example is the limitation upon the accuracy with which distances may be measured by radio techniques (Smith 1960) as imposed by atmospheric irregularities: Thompson, Janes and Kirkpatrick (1960) have shown that the apparent length of a radio path fluctuates in association with measured changes of the refractive index. A study of the distribution of water vapour and heat within turbulent eddies near the ground also provides information that is important to the limitation on precision of microwave surveying techniques (Hay and Pemberton 1962).…”

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confidence: 99%

Investigation of Refractometer Measurements in the Atmosphere at High Relative Humidities and Temperatures

Hay¹,

Turner²

1963

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When US Government drawings, specifications, or other data are used for any purpose other than a definitely related government procurement operation, the government thereby incurs no responsibility nor any obligation whatsoever; and the fact that the government may have formulated, furnished, or in any way supplied the said drawings, specifications, or other data is not to be regarded by implication or otherwise, as in any manner licensing the holder or any other person or corporation, or conveying any rights or permission to manufacture, use, or sell any patented invention that may in any way be related thereto. 11 FOREWORD This report describes research which is part of the graduate studies program of the Department of Physics, University of Western Ontario. The period of study extended from May 1st 1962 to April 30th 1963. The authors are indebted to Dr. P. A. Forsyth, F.R.S.C., Head of the Department, for making available the facilities of the department for this research program. Several members of the Tropospheric Physics Group, unde. >e direction of the senior author, have contributed towards the study reported here. Mr. H. C. Martin, M.Sc, has provided information on the air-flow about the capacitor-type refractometer, and has worked out the programs for computation on the IBM 650 Computer. Mr. J. Kortschinski, a student in the third year of the Engineering Science course at this university, has designed the wind tunnel and supervised its construction while working with the Group during the summer of 1962. Messrs. H. Aitkenhead, K. McColl and D. Stewart, technicians in the Group, have assisted in many aspects of the research program. H. £. Turner, the co-author, would like to acknowledge his indebtedness to the National Research Council of Canada for the Studentship awarded to him during the period of this study. The authors would like to express their sincere appreciation to those outside of the Department of Physics who have contributed in various ways to the research program: They arc grateful to the Chairman of the Defence Research Board and the Chief Superintendent of the Defence Research lelecommunications Establishment in Ottawa for the loan of some of the test instruments: to the Director of the Division of Applied Physics of the National Research Council in Ottawa for arranging for the calibration Ill of a precision resistor upon which the precise temperature measurements

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An analysis of time variations in tropospheric refractive index and apparent radio path length

Cited by 24 publications

References 3 publications

Preliminary Analysis of a Proposed High-Stability Frequency Standard Distribution System

Preliminary Analysis of a Proposed High-Stability Frequency Standard Distribution System

Radio path length stability of ground-to-ground microwave links

Investigation of Refractometer Measurements in the Atmosphere at High Relative Humidities and Temperatures

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