National Repository of Grey Literature 5 records found  Search took 0.01 seconds. 
Total Electron Content Measurements by Single-Frequency GPS Receiver
Rejfek, Luboš ; Pitaš, K. ; Urbář, Jaroslav ; Chmelař, P.
In this paper is described the measurement of the Total Electron Content by the single-frequency GPS receiver. Disadvantage of this method is that it cannot be used for realtime processing. The advantages of the proposed method are that the device is cheaper than dual-frequency GPS receiver and it can reinterpret older valuable measurements by such singlefrequency receivers. The algorithm was tested with the dualfrequency receiver. Signal from selected frequency (f1, or f2) was processed by presented algorithm and results were compared with standard processing of the signals, which is used for the dual-frequency receivers. Results are promising.
Digisonde measurement
Kouba, Daniel ; Mošna, Zbyšek ; Koucká Knížová, Petra ; Boška, Josef ; Rejfek, Luboš
Ionospheric station in Průhonice currently performs its measurements using Digisonda DPS 4D. The vertical profile of the electron concentration can be measured by ionospheric vertical sounding using Ionosonde and Digisonde. The electron concentration profile shows the location of the layers of the ionosphere, the D, E, F1 and F2 layers, and the electron concentration at a given height. Another way to study the behavior of the ionosphere is to measure Doppler shift in ionospheric plasma. The Průhonická observatory is part of the Digisond World Network. The measured data is immediately automatically sent to the GIRO database (
Comparision of devices for monitoring of the ionosphere at the observatory Průhonice
Beran, L. ; Chmelař, P. ; Rejfek, Luboš ; Chum, Jaroslav ; Mošna, Zbyšek
This document is about comparison of the methods ad systems for the measurement of the ionosphere used at the geophysical observatory Pruhonice (50N, 14.5E). Three systems for ionospheric monitoring are installed at the station. The first system for the monitoring of the ionosphere is Digisonde, the second system is countinuous Doppler sounding. Each system has its banefits and weaknesses which are compared in this paper.
Comparison of parametric methods for radar signal processing
Rejfek, Luboš ; Burešová, Dalia ; Fišer, O. ; Brázda, V.
The paper deals with comparison of parametric power spectral density methods for the utilization in the meteorological radar (pulse radar of frequency modulated pulses). We have compared duration of signal processing requested by single methods involved in the test. The methods used are the Auto Regressive model, MUSIC method, Eigen Vector algorithm and CAPON. The best results we have obtained for the AR model.
On Forward and Backward Scattering from Fog and Rain Drops
Fišer, O. ; Rejfek, Luboš ; Brázda, Vladimír
This contribution deals with the backward and forward scattering on dielectrical spheres. The well-known Rayleigh, Mie and Optical regions are discussed for frequencies regions 0.05 to 70 GHz and for optical wavelength of 830 nm. Some of our results fit the published one, some of them are different and the explanation of possible reasons is added. Also the formulas necessary to compute the radar reflectivity or attenuation due to fog and rain are presented.

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2 Rejfek, L.
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