RADIO PHYSICS AND RADIO ASTRONOMY

Subject and Purpose. The work has been aimed at the development and practical implementation of a new method for processing the results of aeronomic and radio astronomical observations that are performed with the help of a total-power radiometer for a variety of elevation angles of the objects. The method proposed makes it possible evaluating the absorption coefficient in the troposphere and current basic parameters of the measuring system. The subject of research is the tropospheric zenith opacity τ, the scattering coefficient β of the antenna system, and noise temperature of the radio receiver together with the antenna.

Methods and Methodology. The method is based on a new approach to mathematical processing of the observational results. In contrast to the widely used dual-parameter least squares method, we propose to vary one of the parameters, while determining its most probable value as such corresponding to minimal mean square deviations as functions of the parameter’s value. The estimates obtained within this procedure are regarded as the most probable values of the atmospheric absorption constant  (troposphere opacity in the zenith direction), the scattering coefficient of the antenna system, and the noise temperature of the radio receiver (together with the antenna).
The technique proposed has been named the "maximum confidence" method.

Results. The method developed was first demonstrated and verified on a mathematical model. The same way the experimental data obtained in the 3-mm range of wavelengths, with diff erent receivers and meteorological circumstances were processed. The effectiveness of the "maximum confidence" method proposed by the authors has been proven.

Conclusions. A new method of processing the data of aeronomic observations allows us to increase the accuracy of measurements of the tropospheric zenith opacity. In addition, it gives possibility to determine the scattering coefficient of the antenna and to monitor the
noise temperature of the radio receiver. The latter has its own importance as a method of determining the parameters of the receiving system during real operation rather than separately on specialized measuring stands.

Keywords: aeronomy, radio astronomy, atmospheric profiles, millimeter waves

Manuscript submitted  28.03.2024

Radio phys. radio astron. 2024, 29(4): 247-254

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