A theoretical and experimental study of angular scintillations in earth space paths

Author

Vilar, Enric ; Smith, Howard

Author_Institution

Portsmouth Polytechnic, Portsmouth, UK

Volume

34

Issue

1

fYear

1986

fDate

1/1/1986 12:00:00 AM

Firstpage

2

Lastpage

10

Abstract

The theoretical framework and experimental results of an antenna offsetting technique which has been used to investigate angle of arrival fluctuations in the microwave region for medium ( $30\\deg$ ) and low elevation ( $9\\deg$ ) angles is presented. The receiver antenna is depointed by a small angle and the antenna gain slope in dB/deg transforms angle fluctuations into amplitude fluctuations. The sensitivity and resolution of the apparatus together with the limitations due to amplitude scintillations, their time variability, and the noise floor of the system are discussed in detail. Experimental results are presented and compared with the theory developed in the paper. The study reveals that the important parameter is the product $C^{2}_{n}L$ and values are presented and discussed. The experimental values for the root mean square (rms) angular deviation $\\sigma (\\theta)$ and of the spectral density $W_{\\theta}(f)$ show a great variability between day and night and between winter and summer with values of $\\sigma (\\theta)$ ranging from below 1 mdeg up to 20 mdeg. Low elevation studies at $9\\deg$ indicate angular scintillations less intense than expected, and never exceeding 4 mdeg.

Keywords

Electromagnetic atmospheric interference; Electromagnetic interference, atmospheric; Electromagnetic propagation in absorbing media; Microwave radio propagation meteorological factors; Aperture antennas; Earth; Fluctuations; Gain; Helium; Microwave theory and techniques; Noise level; Optical interferometry; Receiving antennas; Root mean square;

fLanguage

English

Journal_Title

Antennas and Propagation, IEEE Transactions on

Publisher

ieee

ISSN

0018-926X

Type

jour

DOI

10.1109/TAP.1986.1143720

Filename

1143720