53 research outputs found
ON SOME CEREBROSPINAL FLUID CHANGES DURING THE ACUTE STAGE OF ΓΒ‘EREBRAL INFARCTION
No abstrac
Application of model of mixture of probabilistic distributions for definition of the signals of radiophysical probing
Β© 2016, Allerton Press, Inc.The article describes a model representation of radar probing data in form of a mixture of background and target samples, which is the sum of two random variables with very different parameters. For model development we research the behavior of the central moments of the distribution mix without assuming the distribution law form. An example it is described the detection of the signal at the output of compression system of chirp ionosonde
Simultaneous determine of Doppler shift and group delay time using amplitude modulated chirp-signal
New method of the simultaneous measurement of the frequency dependencies of Doppler shift and group delay time of separate ionosphere modes by means of amplitude modulated chirp signal is presented in this paper. The algorithms of data processing are presented.ΠΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½ΠΎ Π½ΠΎΠ²ΠΈΠΉ ΠΌΠ΅ΡΠΎΠ΄ ΠΎΠ΄Π½ΠΎΡΠ°ΡΠ½ΠΎΠ³ΠΎ Π²ΠΈΠΌΡΡΡΠ²Π°Π½Π½Ρ ΡΠ°ΡΡΠΎΡΠ½ΠΈΡ
Π·Π°Π»Π΅ΠΆΠ½ΠΎΡΡΠ΅ΠΉ Π΄ΠΎΠΏΠΏΠ»Π΅ΡΡΠ²ΡΡΠΊΠΎΠ³ΠΎ Π·ΡΡΠ²Ρ Ρ ΡΠ°ΡΡ Π³ΡΡΠΏΠΎΠ²ΠΎΡ Π·Π°ΡΡΠΈΠΌΠΊΠΈ ΠΎΠΊΡΠ΅ΠΌΠΈΡ
ΡΠΎΠ½ΠΎΡΡΠ΅ΡΠ½ΠΈΡ
ΠΌΠΎΠ΄ Π· Π²ΠΈΠΊΠΎΡΠΈΡΡΠ°Π½Π½ΡΠΌ Π±Π΅Π·ΠΏΠ΅ΡΠ΅ΡΠ²Π½ΠΎΠ³ΠΎ ΠΠ§Π ΡΠΈΠ³Π½Π°Π»Ρ Π· Π°ΠΌΠΏΠ»ΡΡΡΠ΄Π½ΠΎΡ ΠΌΠΎΠ΄ΡΠ»ΡΡΡΡΡ. ΠΠ°Π²Π΅Π΄Π΅Π½ΠΎ ΠΏΠΎΡΡΠ΄ΠΎΠΊ ΠΎΠ±ΡΠΎΠ±ΠΊΠΈ Π΄Π°Π½ΠΈΡ
ΠΏΡΠ΄ ΡΠ°Ρ Π²ΠΈΠΌΡΡΡΠ²Π°Π½Π½Ρ
Using the Risk Function in the Problem of Detection of Radiophysical Sounding Signals
Β© 2017 Springer Science+Business Media New YorkWe propose a model of a two-component mixture for the statistical description of a radiophysical sounding signal at the output of the receiver of a signal with linear frequency modulation. Within this framework, it is found that the risk function can be used to detect readings of the second component in the mixture for small reading amounts. The method for detection of the second mixture component by using the risk function of the mixture on the basis of learning samples is proposed and tested experimentally for the first time
Use of Hazard Function for Signal Detection on Ionograms
Β© 2004-2012 IEEE. This letter considers a new method for sample detection of ionospheric propagation modes at the receiver output of a chirp ionosonde. The method is based on the use of the hazard function. Within the framework of the two-component mixture model, it is shown that the hazard function can be used to detect samples of the second component in the mixture when the corresponding fraction of samples in the total number is small. The implementation of the method is carried out using training sets. An average normalized hazard function is constructed for the training set not containing the signal. Normalization is carried out in such a way that the hazard function can be considered as a probability density function of a certain random variable. We used Pearson's statistic to test the agreement between the average normalized hazard function of samples that do not contain the signal and an arbitrary normalized hazard function. The critical value of the statistic was determined using the Neyman-Pearson criterion. The effectiveness of the proposed method has been tested for the determination of the lowest and maximum observed frequencies of radio paths from oblique ionospheric sounding ionograms obtained in the Russian network of circumpolar radio paths. The method suggested in this letter can be used not only when processing ionograms but also for the detection of samples of signals of arbitrary nature against a background noise, provided that statistical signal-to-noise ratios are similar to those considered here
Ionospheric Effects of a Solar Eclipse of March 20, 2015 on Oblique Sounding Paths in the Eurasian Longitudinal Sector
Β© 2016, Springer Science+Business Media New York.The results of measuring HF signals on oblique chirp sounding paths in the Eurasian region during a solar eclipse of March 20, 2015 and the neighboring days are presented. The solar eclipse took place against the background of a strong magnetic storm. It was established that during the solar eclipse on oblique sounding paths of different length and orientation the decrease in the maximum observable frequency for the F mode (MOF-F) and the lowest observable frequency for the F mode (LOF-F) was 8β14% and 22β33%, respectively. During the eclipse, the signal amplitude increased by 3β5 dB. On the LovozeroβNizhny Novgorod path in the maximum phase of the solar eclipse, the electron density decrease in the ionospheric E and F2 layers at the midpoint of the path reached 37% and 22%, respectively. According to the MOF and LOF variation measurements for various modes, the group delay time of radio signals, and the results of spectral analysis, it was found that in the eclipse there were wave disturbances with a period of 25 to 50 min. However, quasi-periodic variations of MOF-F and LOF-F having a a period of 50 to 80 min but which started before the eclipse were detected on some paths. Probably, in these cases, the variations were a result of the superposition of disturbances from two sources, namely, the magnetic storm and the solar eclipse
Π£ΠΠ ΠΠ©ΠΠΠΠΠ― ΠΠΠ’ΠΠΠΠ’ΠΠ§ΠΠ‘ΠΠΠ― ΠΠΠΠΠΠ¬ ΠΠΠΠΠΠΠΠΠΠ ΠΠΠΠΠ ΠΠΠΠΠ ΠΠΠΠ ΠΠΠ’ΠΠ’ΠΠΠ¬ΠΠΠΠ ΠΠΠΠΠ ΠΠ’Π
Strong reduction of new aircraft design period using new technology based on artificial intelligence is the key problem mentioned in forecasts of leading aerospace industry research centers. This article covers the approach to development of quick aerodynamic design methods based on artificial intelligence neural system. The problem is being solved for the classical scheme of small sized unmanned aircraft vehicle (UAV). The principal parts of the method are the mathematical model of layout, layout generator of this type of aircraft is built on aircraft neural networks, automatic selection module for cleaning variety of layouts generated in automatic mode, robust direct computational fluid dynamics method, aerodynamic characteristics approximators on artificial neural networks.Methods based on artificial neural networks have intermediate position between computational fluid dynamics methods or experiments and simplified engineering approaches. The use of ANN for estimating aerodynamic characteris-tics put limitations on input data. For this task the layout must be presented as a vector with dimension not exceeding sev-eral hundred. Vector components must include all main parameters conventionally used for layouts description and completely replicate the most important aerodynamics and structural properties.The first stage of the work is presented in the paper. Simplified mathematical model of small sized UAV was developed. To estimate the range of geometrical parameters of layouts the review of existing vehicle was done. The result of the work is the algorithm and computer software for generating the layouts based on ANN technolo-gy. 10000 samples were generated and the dataset containig geometrical and aerodynamic characteristics of layoutwas created.Π ΡΡΠ½Π΄Π°ΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΡΡ
ΠΏΡΠΎΠ³Π½ΠΎΠ·Π°Ρ
Π²Π΅Π΄ΡΡΠΈΡ
Π½Π°ΡΡΠ½ΡΡ
ΡΠ΅Π½ΡΡΠΎΠ² Π°ΡΡΠΎΠΊΠΎΡΠΌΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΈΠ½Π΄ΡΡΡΡΠΈΠΈ ΠΏΠΎΡΡΠ°Π²Π»Π΅Π½Π° Π·Π°Π΄Π°ΡΠ° ΡΡΡΠ΅ΡΡΠ²Π΅Π½Π½ΠΎ ΡΠΎΠΊΡΠ°ΡΠΈΡΡ Π²ΡΠ΅ΠΌΡ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠΈ Π½ΠΎΠ²ΡΡ
Π»Π΅ΡΠ°ΡΠ΅Π»ΡΠ½ΡΡ
Π°ΠΏΠΏΠ°ΡΠ°ΡΠΎΠ² Π·Π° ΡΡΠ΅Ρ ΡΠΎΠ·Π΄Π°Π½ΠΈΡ Π½ΠΎΠ²ΠΎΠ³ΠΎ ΠΏΠΎΠΊΠΎΠ»Π΅Π½ΠΈΡ ΡΡΠ΅Π΄ΡΡΠ² ΠΏΡΠΎΠ΅ΠΊΡΠΈΡΠΎΠ²Π°Π½ΠΈΡ Ρ ΠΏΡΠΈΠ²Π»Π΅ΡΠ΅Π½ΠΈΠ΅ΠΌ ΡΠΈΡΡΠ΅ΠΌ ΠΈΡΠΊΡΡΡΡΠ²Π΅Π½Π½ΠΎΠ³ΠΎ ΠΈΠ½ΡΠ΅Π»Π»Π΅ΠΊΡΠ°. Π Π΄Π°Π½Π½ΠΎΠΉ ΡΡΠ°ΡΡΠ΅ ΡΠ°ΡΡΠΌΠ°ΡΡΠΈΠ²Π°Π΅ΡΡΡ ΠΏΠΎΠ΄Ρ
ΠΎΠ΄ ΠΊ ΡΠ°Π·Π²ΠΈΡΠΈΡ Π±ΡΡΡΡΡΡ
ΠΌΠ΅ΡΠΎΠ΄ΠΎΠ² Π°ΡΡΠΎΠ΄ΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΏΡΠΎΠ΅ΠΊΡΠΈΡΠΎΠ²Π°Π½ΠΈΡ, ΠΎΡΠ½ΠΎΠ²Π°Π½Π½ΡΡ
Π½Π° ΠΏΡΠΈΠΌΠ΅Π½Π΅Π½ΠΈΠΈ ΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΠΈ ΠΈΡΠΊΡΡΡΡΠ²Π΅Π½Π½ΡΡ
Π½Π΅ΠΉΡΠΎΠ½Π½ΡΡ
ΡΠ΅ΡΠ΅ΠΉ. Π Π΅ΡΠ°Π΅ΡΡΡ Π·Π°Π΄Π°ΡΠ° ΡΠΎΠ·Π΄Π°Π½ΠΈΡ Π±ΡΡΡΡΠΎΠ³ΠΎ ΠΈΠ½ΡΠ΅ΡΠΏΠΎΠ»ΡΡΠΈΠΎΠ½Π½ΠΎΠ³ΠΎ ΠΌΠ΅ΡΠΎΠ΄Π° Π°ΡΡΠΎΠ΄ΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠ°ΡΡΠ΅ΡΠ° ΠΊΠΎΠΌΠΏΠΎΠ½ΠΎΠ²ΠΊΠΈ ΠΌΠ°Π»ΠΎΠ³ΠΎ Π»Π΅ΡΠ°ΡΠ΅Π»ΡΠ½ΠΎΠ³ΠΎ Π°ΠΏΠΏΠ°ΡΠ°ΡΠ° ΡΠ°ΠΌΠΎΠ»Π΅ΡΠ½ΠΎΠΉ ΡΡ
Π΅ΠΌΡ. Π‘ΠΎΡΡΠ°Π²Π½ΡΠΌΠΈ ΡΠ°ΡΡΡΠΌΠΈ ΠΌΠ΅ΡΠΎΠ΄Π° ΡΠ²Π»ΡΡΡΡΡ ΠΌΠ°ΡΠ΅ΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠ°Ρ ΠΌΠΎΠ΄Π΅Π»Ρ ΠΊΠΎΠΌΠΏΠΎΠ½ΠΎΠ²ΠΊΠΈ, Π³Π΅Π½Π΅ΡΠ°ΡΠΎΡ ΠΊΠΎΠΌΠΏΠΎΠ½ΠΎΠ²ΠΎΠΊ Π΄Π°Π½Π½ΠΎΠ³ΠΎ ΠΊΠ»Π°ΡΡΠ° Π½Π° Π±Π°Π·Π΅ ΡΠ΅ΠΏΠ»ΠΈΠΊΠ°ΡΠΈΠ²Π½ΡΡ
ΠΈΡΠΊΡΡΡΡΠ²Π΅Π½Π½ΡΡ
Π½Π΅ΠΉΡΠΎΠ½Π½ΡΡ
ΡΠ΅ΡΠ΅ΠΉ, Π°Π²ΡΠΎΠΌΠ°ΡΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Π½ΡΠΉ Π°Π»Π³ΠΎΡΠΈΡΠΌ Π²ΡΠ±ΡΠ°ΠΊΠΎΠ²ΠΊΠΈ Π½Π΅ΡΠ΄Π°ΡΠ½ΡΡ
ΠΊΠΎΠΌΠΏΠΎΠ½ΠΎΠ²ΠΎΠΊ, ΡΠΎΠ·Π΄Π°Π½Π½ΡΡ
Π² Π°Π²ΡΠΎΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠΌ ΡΠ΅ΠΆΠΈΠΌΠ΅, ΡΠΎΠ±Π°ΡΡΠ½ΡΠΉ ΠΏΡΡΠΌΠΎΠΉ ΠΌΠ΅ΡΠΎΠ΄ Π°ΡΡΠΎΠ΄ΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠ°ΡΡΠ΅ΡΠ° ΠΊΠΎΠΌΠΏΠΎΠ½ΠΎΠ²ΠΎΠΊ, Π°ΠΏΠΏΡΠΎΠΊΡΠΈΠΌΠ°ΡΠΎΡΡ Π½Π° Π±Π°Π·Π΅ ΠΈΡΠΊΡΡΡΡΠ²Π΅Π½Π½ΡΡ
Π½Π΅ΠΉΡΠΎΠ½Π½ΡΡ
ΡΠ΅ΡΠ΅ΠΉ.ΠΠ΅ΡΠΎΠ΄Ρ, ΠΎΡΠ½ΠΎΠ²Π°Π½Π½ΡΠ΅ Π½Π° ΠΏΡΠΈΠΌΠ΅Π½Π΅Π½ΠΈΠΈ ΠΈΡΠΊΡΡΡΡΠ²Π΅Π½Π½ΡΡ
Π½Π΅ΠΉΡΠΎΠ½Π½ΡΡ
ΡΠ΅ΡΠ΅ΠΉ, Π·Π°Π½ΠΈΠΌΠ°ΡΡ Π½Π΅ΠΊΠΎΡΠΎΡΠΎΠ΅ ΠΏΡΠΎΠΌΠ΅ΠΆΡΡΠΎΡΠ½ΠΎΠ΅ ΠΌΠ΅ΡΡΠΎ ΠΌΠ΅ΠΆΠ΄Ρ ΠΌΠ΅ΡΠΎΠ΄Π°ΠΌΠΈ ΡΠ΅ΡΠ΅Π½ΠΈΡ ΠΊΡΠ°Π΅Π²ΡΡ
Π·Π°Π΄Π°Ρ Π²ΡΡΠΈΡΠ»ΠΈΡΠ΅Π»ΡΠ½ΠΎΠΉ Π°ΡΡΠΎΠ΄ΠΈΠ½Π°ΠΌΠΈΠΊΠΈ ΠΈΠ»ΠΈ ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠΎΠΌ ΠΈ ΡΠΏΡΠΎΡΠ΅Π½Π½ΡΠΌΠΈ (ΠΈΠ½ΠΆΠ΅Π½Π΅ΡΠ½ΡΠΌΠΈ) ΠΌΠ΅ΡΠΎΠ΄Π°ΠΌΠΈ. ΠΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ ΠΈΡΠΊΡΡΡΡΠ²Π΅Π½Π½ΡΡ
Π½Π΅ΠΉΡΠΎΠ½Π½ΡΡ
ΡΠ΅ΡΠ΅ΠΉ Π΄Π»Ρ ΠΎΡΠ΅Π½ΠΊΠΈ Π°ΡΡΠΎΠ΄ΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠΈΡ
Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈ-ΡΡΠΈΠΊ Π½Π°ΠΊΠ»Π°Π΄ΡΠ²Π°Π΅Ρ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Π½ΡΠ΅ ΠΎΠ³ΡΠ°Π½ΠΈΡΠ΅Π½ΠΈΡ Π½Π° ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½ΠΈΠ΅ Π²Ρ
ΠΎΠ΄Π½ΠΎΠΉ ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΈ. ΠΡΠΈ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠΈ ΠΈΡΠΊΡΡΡΡΠ²Π΅Π½Π½ΡΡ
Π½Π΅ΠΉΡΠΎΠ½Π½ΡΡ
ΡΠ΅ΡΠ΅ΠΉ Π² ΠΊΠ°ΡΠ΅ΡΡΠ²Π΅ Π°ΠΏΠΏΡΠΎΠΊΡΠΈΠΌΠ°ΡΠΎΡΠ° Π°ΡΡΠΎΠ΄ΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠΈΡ
Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊ ΡΠ°Π·ΠΌΠ΅ΡΠ½ΠΎΡΡΡ Π²Ρ
ΠΎΠ΄Π½ΠΎΠ³ΠΎ Π²Π΅ΠΊΡΠΎΡΠ°, ΠΎΠΏΠΈΡΡΠ²Π°ΡΡΠ΅Π³ΠΎ ΠΊΠΎΠΌΠΏΠΎΠ½ΠΎΠ²ΠΊΡ, Π½Π΅ Π΄ΠΎΠ»ΠΆΠ½Π° ΠΏΡΠ΅Π²ΡΡΠ°ΡΡ Π½Π΅ΡΠΊΠΎΠ»ΡΠΊΠΈΡ
ΡΠΎΡΠ΅Π½. ΠΡΠΈ ΡΡΠΎΠΌ ΠΊΠΎΠΌΠΏΠΎΠ½Π΅Π½ΡΡ Π²Ρ
ΠΎΠ΄Π½ΠΎΠ³ΠΎ Π²Π΅ΠΊΡΠΎΡΠ° Π΄ΠΎΠ»ΠΆΠ½Ρ Π²ΠΊΠ»ΡΡΠ°ΡΡ Π² ΡΠ΅Π±Ρ Π²ΡΠ΅ ΠΎΡΠ½ΠΎΠ²Π½ΡΠ΅ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΡ, ΡΡΠ°Π΄ΠΈΡΠΈΠΎΠ½Π½ΠΎ ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΠ΅ΠΌΡΠ΅ Π΄Π»Ρ ΠΎΠΏΠΈΡΠ°Π½ΠΈΡ ΠΊΠΎΠΌΠΏΠΎΠ½ΠΎΠ²ΠΎΠΊ ΡΠ°ΡΡΠΌΠ°ΡΡΠΈΠ²Π°Π΅ΠΌΠΎΠ³ΠΎ ΠΊΠ»Π°ΡΡΠ° ΠΈ ΠΏΠΎΠ»Π½ΠΎΡΡΡΡ ΠΎΡΡΠ°ΠΆΠ°ΡΡΠΈΠ΅ Π½Π°ΠΈΠ±ΠΎΠ»Π΅Π΅ ΡΡΡΠ΅ΡΡΠ²Π΅Π½Π½ΡΠ΅ Π°ΡΡΠΎΠ΄ΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΈ ΠΊΠΎΠ½ΡΡΡΡΠΊΡΠΈΠ²Π½ΡΠ΅ ΡΠ²ΠΎΠΉΡΡΠ²Π°.Π ΡΡΠ°ΡΡΠ΅ ΠΏΡΠΈΠ²Π΅Π΄Π΅Π½Ρ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡ ΠΏΠ΅ΡΠ²ΠΎΠ³ΠΎ ΡΡΠ°ΠΏΠ° ΡΠ°Π±ΠΎΡ. ΠΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½Π° ΠΎΠ±ΠΎΠ±ΡΠ΅Π½Π½Π°Ρ ΠΌΠ°ΡΠ΅ΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠ°Ρ ΠΌΠΎΠ΄Π΅Π»Ρ ΠΊΠΎΠΌΠΏΠΎΠ½ΠΎΠ²ΠΎΠΊ ΠΌΠ°Π»ΠΎΡΠ°Π·ΠΌΠ΅ΡΠ½ΡΡ
Π±Π΅ΡΠΏΠΈΠ»ΠΎΡΠ½ΡΡ
Π»Π΅ΡΠ°ΡΠ΅Π»ΡΠ½ΡΡ
Π°ΠΏΠΏΠ°ΡΠ°ΡΠΎΠ². ΠΠ»Ρ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ Π΄ΠΈΠ°ΠΏΠ°Π·ΠΎΠ½Π° ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΡ Π³Π΅ΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² ΠΊΠΎΠΌΠΏΠΎΠ½ΠΎΠ²ΠΊΠΈ ΡΠ΄Π΅Π»Π°Π½ ΠΎΠ±Π·ΠΎΡ Π°ΠΏΠΏΠ°ΡΠ°ΡΠΎΠ² Π΄Π°Π½Π½ΠΎΠ³ΠΎ ΠΊΠ»Π°ΡΡΠ°. Π Π΅Π·ΡΠ»ΡΡΠ°ΡΠΎΠΌ ΡΠ°Π±ΠΎΡΡ ΡΠ²Π»ΡΠ΅ΡΡΡ Π°Π»Π³ΠΎΡΠΈΡΠΌ ΠΈ ΠΊΠΎΠΌΠΏΡΡΡΠ΅ΡΠ½Π°Ρ ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌΠ° Π½Π° Π±Π°Π·Π΅ ΠΈΡΠΊΡΡΡΡΠ²Π΅Π½Π½ΡΡ
Π½Π΅ΠΉΡΠΎΠ½Π½ΡΡ
ΡΠ΅ΡΠ΅ΠΉ Π΄Π»Ρ Π³Π΅Π½Π΅ΡΠ°ΡΠΈΠΈ ΠΊΠΎΠΌΠΏΠΎΠ½ΠΎΠ²ΠΎΠΊ Π΄Π°Π½Π½ΠΎΠ³ΠΎ ΠΊΠ»Π°ΡΡΠ°. Π‘Π³Π΅Π½Π΅ΡΠΈΡΠΎΠ²Π°Π½ΠΎ 10000 ΠΊΠΎΠΌΠΏΠΎΠ½ΠΎΠ²ΠΎΠΊ, Π²ΡΠ±ΡΠ°ΠΊΠΎΠ²ΠΊΠ° Π½Π΅ΡΠ΄Π°ΡΠ½ΡΡ
ΠΏΠΎΠ·Π²ΠΎΠ»ΠΈΠ»Π° ΡΠΎΠ·Π΄Π°ΡΡ Π½Π°Π±ΠΎΡ Π΄Π°Π½Π½ΡΡ
. ΠΡΠ±ΡΠ°Π½, ΡΠ΅ΡΡΠΈΡΠΎΠ²Π°Π½ ΠΈ ΠΏΠΎΠ΄Π³ΠΎΡΠΎΠ²Π»Π΅Π½ ΠΊ ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½ΠΈΡ ΡΠΈΡΠ»Π΅Π½Π½ΡΡ
ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠΎΠ² ΠΏΡΡΠΌΠΎΠΉ ΠΌΠ΅ΡΠΎΠ΄ Π΄Π»Ρ Π²ΡΠΏΠΎΠ»Π½Π΅Π½ΠΈΡ Π°ΡΡΠΎΠ΄ΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠ°ΡΡΠ΅ΡΠ°
Impact of a Strong Magnetic Storm and Two X-Ray Flares on the Ionospheric HF Channel in the Summer Solstice of 2015 According to Oblique Sounding in the Eurasian Region
Β© 2017, Springer Science+Business Media, LLC. We present the results of observations of the impact a strong magnetic storm and two X-ray flares in the summer solstice of 2015 on the HF signal characteristics during oblique sounding of the ionosphere in the Eurasian region. It was found that the negative phase of the magnetic storm led to a strong degradation of the ionospheric channel, up to a long blackout on the paths adjacent to the subauroral latitudes. On the midlatitude paths, a decrease in the maximum observable frequency of the F layer reached 50% with respect to the average values for an undisturbed ionosphere. The propagation velocity of the negative phase of a disturbance from the subauroral to the midlatitude ionosphere is determined (it is equal to about 100 m/s). It is shown that during a magnetic storm the least observable frequency and the average signal-to-noise ratio for the propagation mode via the sporadic E s layer correlate well with the auroral AE index. Anomalous signals were detected in the main phase of the magnetic storm on the CyprusβRostov-on-Don path when a chirp ionosondeβradio direction finder was operated in the over-the-horizon HF radar mode. On the basis of modeling and comparison with experimental data, it is shown that the anomalous signals are due to scattering of radio waves by small-scale irregularities located in the subauroral ionospheric F region
Impact of a Strong Magnetic Storm and Two X-Ray Flares on the Ionospheric HF Channel in the Summer Solstice of 2015 According to Oblique Sounding in the Eurasian Region
Β© 2017 Springer Science+Business Media, LLC We present the results of observations of the impact a strong magnetic storm and two X-ray flares in the summer solstice of 2015 on the HF signal characteristics during oblique sounding of the ionosphere in the Eurasian region. It was found that the negative phase of the magnetic storm led to a strong degradation of the ionospheric channel, up to a long blackout on the paths adjacent to the subauroral latitudes. On the midlatitude paths, a decrease in the maximum observable frequency of the F layer reached 50% with respect to the average values for an undisturbed ionosphere. The propagation velocity of the negative phase of a disturbance from the subauroral to the midlatitude ionosphere is determined (it is equal to about 100 m/s). It is shown that during a magnetic storm the least observable frequency and the average signal-to-noise ratio for the propagation mode via the sporadic E s layer correlate well with the auroral AE index. Anomalous signals were detected in the main phase of the magnetic storm on the CyprusβRostov-on-Don path when a chirp ionosondeβradio direction finder was operated in the over-the-horizon HF radar mode. On the basis of modeling and comparison with experimental data, it is shown that the anomalous signals are due to scattering of radio waves by small-scale irregularities located in the subauroral ionospheric F region
Impact of heliogeophysical disturbances on ionospheric HF channels
Β© 2017 COSPAR. The article presents the results of the observation of a strong magnetic storm and two X-ray flares during the summer solstice in 2015, and their impact on the HF signals characteristics in ionospheric oblique sounding. It was found that the negative phase of the magnetic storm led to a strong degradation of the ionospheric channel, ultimately causing a long blackout on paths adjacent to subauroral latitudes. On mid-latitude paths, the decrease in 1FMOF reached βΌ50% relative to the average values for the quiet ionosphere. It is shown that the propagation conditions via the sporadic Es layer during the magnetic storm on a subauroral path are substantially better than those for F-mode propagation via the upper ionosphere. The delay of the sharp decrease in 1FMOF during the main phase of the magnetic storm allowed us to determine the propagation velocity of the negative phase disturbances (βΌ100. m/s) from subauroral to mid-latitude ionosphere along two paths: Lovozero - Yoshkar-Ola and Cyprus - Nizhny Novgorod. It is shown that both the LOF and the signal/noise ratio averaged over the frequency band corresponding to the propagation mode via the sporadic Es layer correlate well with the auroral AE index. Using an over-the-horizon chirp radar with a bistatic configuration on the Cyprus - Rostov-on-Don path, we located small-scale scattering irregularities responsible for abnormal signals in the region of the equatorial boundary of the auroral oval
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