RU2394371C1 - Device for determining optimum working frequencies of ionospheric radio channel - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: device includes GPS receiver with antenna, time synchronisation unit, radio receiver (RR) with receiving antenna, which includes high frequency amplifier, the first mixer, chirp signal generator, filter of the first intermediate frequency and amplifier of the first intermediate frequency, the second mixer, heterodyne oscillator, filter of the second intermediate frequency and amplifier of the second intermediate frequency; in addition, the device includes analogue-to-digital converter of the second intermediate frequency and multi-stream computer intended for determining optimum working frequencies of ionospheric radio channel as per the data of inclined sounding by processing, calculation and selection of sections of frequencies with minimum error probability and maximum reliability of short-wave radio communication.

EFFECT: possibility of selecting the sections of frequencies of ionospheric radio channel with minimum error probability and maximum reliability of short-wave radio communication for various types of signal.

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Description

The invention relates to radio engineering, is designed to quickly determine the optimal operating frequencies (ORC) of the ionospheric radio channel according to oblique sounding of the ionosphere and can be used to provide highly reliable adaptive KB radio communications by dynamically controlling the frequency resource of the radio link.

Despite the development of satellite and fiber communication lines, KB radio communication still plays an important role in solving various applied problems. Its advantages are its long range, high mobility, survivability and low cost compared to other types of communications. The main problem of KB radio communication is the unsteadiness of the ionospheric radio channel, caused primarily by the influence of various kinds of perturbations of natural / artificial origin and interference caused by extraneous radio stations. The use of predictive models of the ionospheric KB channel does not provide the necessary quality of radio communications, especially on radio links at high latitudes, where there are no models that adequately describe the state of the ionosphere, especially in perturbed conditions. To control the frequency resource of a radio link under conditions of non-stationary channel, it is necessary to constantly monitor the current ionospheric situation and control the channel load by the interference level. Based on the results of diagnostics of the ionosphere channel, it is possible to determine the optimal time-frequency intervals by signal / noise level, fading (multipath), error probability to ensure high reliability of communication. The key characteristics of the ionospheric radio channel, the operational data of which are necessary for matching narrow-band and wide-band communication systems with the information transmission channel, are: signal-to-noise ratio, ionospheric turbidity coefficient (power ratio of the regular and fluctuation signal components), beam delay range (channel multipath) , frequency dispersion (dτ / df), characterizing the dependence of the time of group propagation of the radio signal (τ) on the path from frequency (f). Using these parameters allows the adaptation of KB radio communication systems in frequency, transmitter power, information transfer rate, type of radio signal and its processing method to ensure the required reliability of radio communication.

Known methods and devices (RU 2010429, RU 1838880, RU 2001529) that evaluate the state of radio channels by measuring and comparing a limited number of parameters (noise level and passing a test signal), which, however, does not provide a comprehensive adaptation of the communication system to the current state of the ionosphere and As a result, it does not lead to a noticeable increase in the reliability of communication, especially in conditions of increased magnetic-ionospheric disturbance. In addition, the known methods and devices have a significant drawback, namely, they do not measure the distance-frequency characteristic (DFC) of the radio links. This limits their strategic possibilities when deciding to change the parameters of a communication system under conditions of a rapid and significant change in the ionospheric environment, for example, during magnetic storms, when anomalous propagation channels arise (“side” propagation through scattering by intense inhomogeneities, waveguide propagation). In this case, the selected frequency in a short time can "go" either into the multipath range, or even "leave" from the transmission range, i.e. the communication channel will be unstable. This will lead to a deterioration in the quality of communication and the need for repeated interrogation by selecting frequencies to determine the best communication frequency, which in turn leads to the need to open the communication channel, thereby facilitating the interception of information and the suppression of the communication system.

The closest analogue is a device (RU 2223601) for determining noise-resistant channels of communication KB. However, the known device does not allow to determine the key parameter of the ionospheric channel - the turbidity coefficient (power ratio of the regular and fluctuation components of the signal) without changing the composition of the hardware-software complex, which would lead to the achievement of the maximum possible reliability of KB radio communication.

The problem to which the invention is directed, is to provide highly reliable adaptive KB radio communications.

This problem is solved using the technical result, which consists in increasing the reliability of determining the optimal operating frequencies of the ionospheric radio channel.

The proposed device allows you to determine the optimal operating frequency of the ionospheric radio channel using a specially developed spectral processing algorithm for the difference signal of an inclined LFM sounding, which selects the mirror and scattered components of the signal transmitted through the ionospheric radio channel, and calculates, on this basis, the probability of error and reliability of communication in the entire frequency range of the passage of radio waves on of a given radio link and selection of frequency sections with the least probability of error and the greatest reliability of KB radio communication for various types of signal.

This result is achieved in that in a device containing a GPS receiver with an antenna, a time synchronization unit, the first input of which is connected to the output of the GPS receiver, a radio receiving device (RPU) with a receiving antenna, a receiving device that includes a high-frequency amplifier is used as the RPU, the first mixer, the first input of which is connected to the output of the high-frequency amplifier, a linear frequency-modulated (LFM) signal generator, the output of which is connected to the second input of the first mixer, and the first input of the generator a chirp of the LFM signal is connected to the first output of the time synchronization unit, a filter of the first intermediate frequency and an amplifier of the first intermediate frequency, connected in series at the output of the first mixer, a second mixer, the first input of which is connected to the output of the amplifier of the first intermediate frequency, a local oscillator, the output of which is connected to the second input the second mixer, the filter of the second intermediate frequency and the amplifier of the second intermediate frequency, sequentially connected at the output of the second mixer, in addition to the devices additionally included an analog-to-digital converter of the second intermediate frequency and a multi-threaded computer designed to determine the optimal operating frequencies of the ionospheric radio channel from the data of oblique sounding by processing, calculating and selecting frequency sections with the least error probability and the greatest reliability of radio communication KB, while the output of the second intermediate frequency amplifier is connected to the first input of the analog-to-digital converter of the second intermediate frequency, the second input of which is connected to the W the output of the time synchronization unit, and the output of the analog-to-digital converter of the second intermediate frequency is connected to the input of the multithreaded computer, the first output of which is connected to the second input of the time synchronization unit, and the second output of the multithreaded computer is connected to the second input of the chirp signal generator.

Figure 1 shows the structural diagram of the device. The device includes a GPS antenna 1 connected to the GPS receiver 2, a time synchronization unit 3, the first input of which is connected to the output of the GPS receiver 2, a receiving antenna 4 connected to the receiving device 5 (circled in dashed line in FIG. 1), which includes a high amplifier frequency 6, the first mixer 7, the first input of which is connected to the output of the high-frequency amplifier 6, the LFM signal generator 8, the output of which is connected to the second input of the first mixer 7, and the first input of the LFM generator 8 is connected to the first output of the temporary block synchronization 3, the filter of the first intermediate frequency (FPF1) 9 and the amplifier of the first intermediate frequency (UPCH1) 10, sequentially connected at the output of the first mixer 7, the second mixer 11, the first input of which is connected to the output of the amplifier of the first intermediate frequency 10, local oscillator 12, the output of which connected to the second input of the second mixer 11, the filter of the second intermediate frequency (FPF2) 13 and the amplifier of the second intermediate frequency (UPCH2) 14, sequentially connected at the output of the second mixer 11. In addition, the device is additionally included us analog-digital converter of the second intermediate frequency (ADC) 15 and a multi-threaded computer 16 (enclosed in a chain line in Figure 1) adapted to calculate the optimum operating frequency ionospheric radio channel by selecting a frequency of sites with the lowest probability of error and the most reliable radio KB. The multi-threaded computer 16 contains a block for obtaining quadrature components of the difference signal 17, the input of which is connected to the output of the ADC 15, a block for estimating the spectral power density (PSD) of a signal and noise using a multi-window method (MTM method) in a wide and narrow band, detecting the rays, determining their number n, amplitudes α _j , delays τ _j , turbidity coefficient β 18, the input of which is connected to the output of block 17, a block for cleaning ionograms, extracting frequency branches and forming dependences α _j (f), τ _j (f), σ _N (f) , c / w _{N (f), βj (f} ), determining the least observable frequencies (LF), maximum observed frequencies (MNF), multipath intervals, determining the number of beams at intervals of controlled frequencies, time scattering intervals, coherence band, standard deviation of the s / w ratio σ, reliability estimate of coupling 19, the input of which is connected to the output of block 18, a unit for generating and displaying output information 20, a first input of which is connected to an output of a block 19, a user interface 21, a first output of which is connected to a second input of a unit for generating and displaying output information 20, the second output of the user interface 21 is connected to the second input of the time synchronization unit 3, and the third output of the user interface 21 of the multi-threaded calculator 16 is connected to the second input of the chirp generator 8.

Consider the operation of the device and the functional purpose of the individual units that provide a solution to the main task of the invention - the determination of the optimal operating frequencies KB radio communication according to the data of inclined chirp sounding of the ionosphere.

The LFM signal of the transmitter is received by antenna 4 and from the antenna output is fed to the input of UHF 6 of receiver 5, intended for selection and amplification of high-frequency signals (UHF) in the range from 3 to 30 MHz, from the output of UHF 6 the signal is fed to the first input of the first mixer 7, the second input of which receives a signal from a generator whose functions are performed by a linear frequency-modulated (LFM) synthesizer 8. From the output of the first mixer 7, the difference signal (f _gene -f _prin ) of the first intermediate frequency (IF) is fed to the input of filter 1- th inverter 9, with output to of which the signal is fed to the input of the amplifier of the 1st IF 10, from the output of which the signal is fed to the first input of the 2nd mixer 11, to the second input of which the signal of the local oscillator 12. From the output of the 2nd mixer 11, the signal of the 2nd intermediate frequency is fed to the input of the filter of the 2nd IF 13, the output of which the signal is fed to the input of the amplifier of the 2nd IF 14, the output of which the difference signal is fed to the first input of the analog-to-digital converter (ADC) 15.

The time synchronization of the chirp signal generator 8 and the ADC 15 with the operation of the remote chirp transmitter is performed using the time synchronization block 3. The block consists of programmable hardware clocks that, at the right time, programmed using the user interface 21, give a start pulse. According to this pulse, the LFM signal generator 8 and the single-channel ADC 15 for converting the difference signal are simultaneously launched.

The exact binding of the hardware clock to world time is carried out using a standard GPS receiver 2.

An accurate time synchronization GPS receiver is connected to its own antenna 1.

The complex for receiving and processing the results of chirp sounding is controlled using the user interface 21 of the multi-threaded calculator 16. The tasks of this unit are to program the hardware clock for accurate time synchronization 3, to program the operating mode of the chirp signal generator 8, and to control the output information generation and display unit 20.

The digitized difference signal is processed by a multi-threaded calculator 16. The received difference signal generated at the second intermediate frequency (IF) at the output of the IFA2 14 is digitized by the ADC 15 with a sampling frequency f _d , which is selected depending on the IF value. IF differential signal processing has several advantages:

- excluded sources of measurement errors and interference associated with additional hardware transformations and the detection process;

- it becomes possible to obtain the quadrature components of the difference signal by digital methods without additional hardware units (phase shifters);

- eliminates the dependence of the digitization and processing procedures on the parameters of the hardware low-pass filters RPU.

All further conversions of the digitized difference signal are carried out in the memory of a multi-threaded computing device 16.

In block 17, the digital signal undergoes operations of transfer to the zero frequency to obtain quadrature components, low-pass filtering, and decimation. The quadrature components of the low-frequency complex signal are obtained by multiplying by the cosine (real quadrature component Re (t)) and sine (imaginary quadrature component Im (t)) of a model signal of unit amplitude with a frequency equal to the replaced IF. After low-pass filtering with a digital filter with a bandwidth, which is selected for reasons of the required viewing range of the time delays, the procedure for lowering the sampling frequency (decimation) is performed. The procedures of digitization, filtering, quadrature signal extraction and decimation are constructed in such a way that all processing is carried out automatically in real time in a separate stream of a multi-threaded computer and allows you to receive a continuous complex difference signal of unlimited time duration. As a result, the quadrature components of the digitized difference signal are processed in real time by two streams. One stream is intended for processing a digital complex differential signal in a wide band with separation into separate modes and propagation rays, and evaluating their information parameters. The second processing stream is designed to obtain information parameters in a narrow band. All three streams (one - receiving a complex difference signal and two processing streams in the narrow and wide bands) operate synchronously and in parallel in the memory of a multi-threaded computing device. As a result of the procedures of digitizing, filtering, extracting the quadrature signal and decimating the differential signal at the output of block 17, we obtain a time-discrete complex low-frequency signal (discrete complex envelope of the differential signal), which is input to block 18 to estimate the power spectral density (PSD) of the difference signal .

) за время съема информации. Полоса сигнала Δf, которая определяет диапазон временного рассеяния Δτ, находится по уровню ε=95% от полной энергии сигнала в полосе ЛЧМ приемника. Значение энергии шумов в полосе, согласованной с сигналом, находится произведением вероятного уровня СПМ шумов

на Δf. После этого определяется отношение мощности сигнала к мощности шума.To estimate the spectral power density (PSD) of a difference signal in a wide band, a multi-window spectral analysis method is chosen, which is carried out in block 18. The main advantages of this method for estimating PSDs are: deterministic choice of spectral windows, the ability to work with short time samples, variance analysis of discrete components, high spectral resolution. The multi-window method of spectral analysis of difference signals reflected from the ionosphere makes it possible to achieve high spectral resolution in frequency; based on a formal statistical criterion, detect discrete (mirror) signal components; get the complex amplitudes of the mirror components of the signal; in contrast to the prototype, isolate the PSD of the scattered (continuous) signal components and evaluate its energy; calculate the turbidity coefficient of the ionosphere (the ratio of the energy of the mirror component to the energy of the scattered component β ² ); determine the delay of the partial mirror components of the signal. The multi-window spectral estimation method allows additionally real-time calculation of noise PSD and the ratio of signal power to noise power in a band matched to the signal. The last two values are determined by the histogram method under the assumption that the frequency band of the spectral analysis is much larger than the band of the received signal. This condition is always realized in the spectral processing of a difference signal, since the useful difference signal is a priori narrow-band. For this, a histogram of the PSD levels in the passband of the chirp receiver is constructed numerically on a decibel scale, the maximum of which corresponds to a probable value of the noise spectral density of 101 g (

) during the collection of information. The signal band Δf, which determines the time scattering range Δτ, is at the level ε = 95% of the total signal energy in the LFM band of the receiver. The value of the noise energy in the band matched with the signal is found as the product of the probable level of noise PSD

on Δf. After that, the ratio of signal power to noise power is determined.

, где Т - ширина временного окна спектрального анализа, n - дискретная частота, τ_shift - заданная временная задержка ЛЧМ синтезатора частоты. Как следствие, предложенный метод применительно к анализу разностного сигнала позволяет осуществлять автоматическое обнаружение гармонических составляющих в спектре разностного сигнала и оценивать их параметры, разделять дискретные и непрерывные части СПМ сигнала. Энергетические параметры отдельных лучей вычисляются в реальном масштабе времени и отображаются в координатах амплитуда-частота одновременно с бинарным изображением ионограммы.To obtain a digital image of an ionogram, a sequence of PSD estimates for different time instants (actually for different frequencies) is displayed on a two-dimensional plane in the coordinates of the frequency-time delay. The frequency f = µ ₀ t is plotted along the abscissa, where t is the time from the start of sounding, µ ₀ is the frequency tuning rate. The ordinate axis represents the absolute time delay.

where T is the width of the time window of the spectral analysis, n is the discrete frequency, τ _shift is the specified time delay of the LFM of the frequency synthesizer. As a result, the proposed method as applied to the analysis of the difference signal allows automatic detection of harmonic components in the spectrum of the difference signal and their parameters, separate discrete and continuous parts of the PSD signal. The energy parameters of individual beams are calculated in real time and displayed in amplitude-frequency coordinates simultaneously with the binary image of the ionogram.

At the output of block 18, digital series of values of the complex amplitudes of the mirror components of the signal, the scattered (continuous) signal components, the ionospheric turbidity coefficient (the ratio of the energy of the mirror component to the scattered energy β ² ), the PSD noise and the ratio of the signal power to the noise power in the band consistent with signal, delays the partial mirror components of the signal. This data is fed to the input of block 19, where ionograms are cleaned up and parameters necessary for estimating the probability of error and reliability of communication to determine the optimal operating frequencies of the ionospheric radio channel are calculated.

Figure 2 shows the distance-frequency characteristic (a) and the amplitude-frequency characteristic of the individual signal modes (b).

гистограммным методом. В реальном масштабе времени одновременно с процессом получения параметров лучей по оценкам СПМ выполняется процедура формирования лучей и мод распространения. При этом осуществляется окончательная очистка частотных характеристик от шумов. Лучи и моды распространения формируются на основе сравнения точек в многомерном пространстве частота-задержка-амплитуда. При этом каждая точка, которая первоначально отождествлена с каким-то лучом распространения, характеризуется тремя координатами: f_j - частота, τ_jl - задержка, a_jl - амплитуда соответственно l-го луча на j-й частоте. Количество лучей - n_j и их координаты в трехмерном пространстве определяются в процессе спектральной обработки разностного сигнала.The digital image of the ionogram is cleaned in real time during its construction in block 19. In this case, an adaptive threshold criterion for signal-to-noise ratio in the band of the elementary filter of digital analysis is used (δf = 1 / Т). In the process of constructing a digital image, a sample of a signal of length T is taken. The corresponding band of the LFM signal received during time T is µ ₀ T. Based on this sample, the PSD of the difference signal and the current value of the spectral density of interference in a wide band are estimated

the histogram method. In real time, simultaneously with the process of obtaining the parameters of the rays according to the PSD estimates, the procedure for the formation of rays and propagation modes is performed. In this case, the final cleaning of the frequency characteristics from noise is carried out. Rays and propagation modes are formed based on a comparison of points in a multidimensional frequency-delay-amplitude space. Moreover, each point that is initially identified with some kind of propagation beam is characterized by three coordinates: f _j is the frequency, τ _jl is the delay, and _jl is the amplitude, respectively, of the l-th beam at the j-th frequency. The number of rays - n _j and their coordinates in three-dimensional space are determined in the process of spectral processing of the difference signal.

Figure 3 shows the interference-free chirp chondogram ionogram corresponding to the experimental ionogram shown in figure 2; figa - distance-frequency characteristic, figb - amplitude-frequency characteristic of the individual signal modes.

After the formation of frequency branches, a secondary processing procedure is carried out, during which there are areas of existence limited by the lowest (LF) and maximum (MNP) observed frequencies for each of the branches. The totality of these areas for all frequency branches allows us to determine the multipath intervals - frequency intervals on which there is only one beam, two rays, three rays, etc. From the VLF of all the rays, the VLF path is determined as the maximum frequency of all observed. At the lowest frequencies of all frequency branches, the LF path is determined as the minimum frequency of all observed.

на любой контролируемой частоте f. При этом производная dτ/df для каждой частотной ветви определяется на основе аппроксимации функции τ₁(f) по методу наименьших квадратов в окрестности контролируемой частоты f линейной зависимостью.In the process of sounding to solve the problems of diagnostics of the ionospheric radio channel, it is possible to determine in real time the parameters of the radio channel at fixed controlled frequencies. At controlled frequencies, the following quantities are calculated: the number of rays forming the total field at the receiving point, time scattering intervals, signal-to-noise ratios in the narrow and wide bands, channel coherence bands, amplitudes and delays of the dominant rays, the probability of communication error, and communication reliability. The time scattering interval in a multipath situation is found as the difference between the maximum and minimum of the ray delays forming the total field at the receiving point. In this case, the value of the protective coefficient is used, the meaning of which is that when determining the time scattering interval, only those rays are used whose amplitudes differ from the amplitude of the dominant beam by no more than a predetermined value (protective coefficient). The protection factor is set in decibels. For a single-beam channel, the time-scattering interval is assumed to be equal to the width of the spectral line corresponding to this beam. The individual frequency branches obtained as a result of the above procedure are used to estimate the coherence band according to the formula

at any controlled frequency f. In this case, the derivative dτ / df for each frequency branch is determined based on the approximation of the function τ ₁ (f) by the least squares method in the vicinity of the controlled frequency f by a linear dependence.

In this device, the CRF selection criterion is based on a functional relationship between the probability of a bit error averaged over random channel parameters and the characteristics of the information transmission channel for various types of signals. In this case, the optimal operating frequencies are the frequencies of the communication channel, during the transmission of information on which the probability of a bit error will be less than the acceptable level, and the reliability of communication is higher than the required value.

The calculation of the probability of error and the reliability of communication is according to the following rules. Unlike the prototype, where the Rayleigh channel is accepted a priori, the proposed device allows one to determine the ORC of the communication channel for signals with different fading statistics, including the most common quasi-Rayleigh channel in the ionosphere when both the mirror and scattered signal components are present. For a quasi-Rayleigh channel, the probability of a bit error is calculated by the formula:

where β ² is the ionospheric turbidity coefficient (power ratio of the regular and fluctuation signal components), h ² is the signal-to-noise power ratio.

For broadband signals with incoherent reception with incoherent addition of rays, the probability of error is calculated by the formula:

,

,

where N is the number of rays, p _i is the probability of a bit error for the i-th ray.

Then, the reliability of the connection is calculated, which has the meaning of the probability that the probability of an error does not exceed a given threshold p _add . This quantity is expressed in terms of the probability integral.

,

,

Where

.

.

- среднеквадратичное отклонение отношения сигнал/помеха, выраженное в децибелах. Последняя величина находится по экспериментальным данным в окрестности контролируемой частоты.Here z _add = 101gh ² _add - the allowable value is the ratio of signal power to interference power corresponding to the allowable probability of error p _add , z = z (f) = 101gh ² (f) is the measured value is the ratio of signal power to interference power, z _add and z expressed in decibels

- the standard deviation of the signal-to-noise ratio, expressed in decibels. The latter value is found from experimental data in the vicinity of the controlled frequency.

From the output of block 19, digital series of values that carry information about all the characteristics of the ionospheric radio channel go to the first input of the data generation and display unit 20, to the second input of which information comes from the third output of the user interface 21. In block 20, data is accumulated and visualized, and graphs are plotted. , tables for the commands received from block 21.

To test the operability of the proposed device, a R-399A radio receiver was used as a receiving device, in which the difference signal was taken from the output of the second intermediate frequency, in which the first intermediate frequency f _pc1 = 34785 kHz, the second intermediate frequency f _pc2 = 215 kHz.

The GPS receiver module of the Lassen SKII type was used as a time synchronization block.

As an analog-to-digital converter of intermediate frequency, an external module of fourteen bit ADCs of the E-440 type is used.

Figure 4 in the form of Table 1 shows the results of the operation of the device on the route Cyprus (transmitter power 100 W) - Rostov-on-Don as applied to determining the optimal operating frequencies for various communication systems with the display of key parameters of the ionospheric radio line, which are:

f is the sounding frequency;

N is the number of discrete rays;

Δτ is the time scattering interval;

- отношение мощности сигнала к мощности шума для узкополосных систем связи;

- the ratio of signal power to noise power for narrowband communication systems;

- отношение мощности сигнала к мощности шума для широкополосных систем связи с учетом некогерентного сложения лучей;

- the ratio of signal power to noise power for broadband communication systems, taking into account incoherent addition of rays;

σ _{s / w} is the variance of the ratio of signal power to noise power;

- допустимое значение отношения мощности сигнала к мощности шума для допустимой вероятности ошибки р_ош.доп=3·10^-3;

- the permissible value of the ratio of signal power to noise power for an acceptable error probability p _er.dop = 3 · 10 ^-3 ;

PC - coherence band KB of the radio channel;

τ is the delay for the beam dominating in power;

β ² is the ratio of the power of the regular and fluctuation components of the signal (the coefficient of turbidity of the ionosphere);

p ₁ is the probability of error for narrow-band communication systems for a multipath channel;

F ₁ - the reliability of radio communications for a narrow-band channel with a probability of an admissible error p _er.dop = 3 · 10 ^-3 ;

p ₂ is the probability of error for broadband communication systems for a multipath channel;

F ₂ - the reliability of radio communications for a narrow-band channel with a probability of an admissible error p _er.dop = 3 · 10 ^-3 .

From the data in Table 1, you can select the frequency that corresponds to the required reliability of communication on a given radio link for the current time moment for both narrowband and broadband communication systems. These data are generated after each sensing cycle in real time, for example, every 5 minutes, depending on the operating mode, and can be used to determine the optimal operating frequencies of a connected radio line when the current ionospheric situation changes. For example, if for this session we take the reliability threshold F _pop = 0.9, then, as follows from Table 1, the optimal operating frequencies for a narrow-band communication system will be frequencies: 11.2, 12.4, and 14.4 MHz, and for a broadband communication system, the optimal working frequencies will be: 8.0, 8.4, 8.8, 9.2, 9.6, 10.0, 10.8, 11.2, 11.6, 12.0, 12.4, 12.8, 13.2, 14.0, 14.4, 14.8, 15.2 MHz, for which the communication reliability F> F _pop = 0.9.

On figa, 5b for 12/14/2006 shows the results of the operation of the device on the route Cyprus - Rostov-on-Don during the day according to the reliability of communication F for narrowband (figa) and broadband (fig.5b) multipath channel power of a connected transmitter of 100 W and an admissible probability of a bit error p _add = 3 · 10 ^-3 , based on which the optimal operating frequencies of a connected radio line with a given reliability for a given time of day are determined for various types of connected signals.

Claims (1)

A device for determining the optimal operating frequencies of the ionospheric radio channel, containing a GPS receiver with an antenna, a time synchronization unit, the first input of which is connected to the GPS receiver output, a radio receiving device (RPU) with a receiving antenna, characterized in that a receiving device is used as the RPU, which includes a high-frequency amplifier, a first mixer, the first input of which is connected to the output of a high-frequency amplifier, an LFM signal generator, the output of which is connected to the second input of the first mixer, and the first the first input of the chirp signal generator is connected to the first output of the time synchronization unit, the filter of the first intermediate frequency and the amplifier of the first intermediate frequency, sequentially connected to the output of the first mixer, the second mixer, the first input of which is connected to the output of the amplifier of the first intermediate frequency, the local oscillator, the output of which is connected to the second input of the second mixer, the filter of the second intermediate frequency and the amplifier of the second intermediate frequency, sequentially connected at the output of the second mixer, except о the device additionally includes an analog-to-digital converter of the second intermediate frequency and a multi-threaded computer designed to determine the optimal operating frequencies of the ionospheric radio channel from the data of oblique sounding by processing, calculating and selecting frequency sections with the least error probability and the highest reliability of radio communication KB, while the amplifier output is second intermediate frequency is connected to the first input of an analog-to-digital converter of the second intermediate frequency, the second input of which The key to the second output of the timing unit, and the output of analog-to-digital converter of the second intermediate frequency is connected to the threaded input calculator, a first output of which is connected to a second input timing block, and the second output multithreaded calculator connected to the second input of the chirp signal generator.

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