RU2294546C2 - Method for identification of radio-radiation - Google Patents

Abstract

FIELD: radio engineering, possible use in radio direction finders, systems of radio control, radio location, radio astronomy.

SUBSTANCE: for constant level of correct identification equal to 0,9 with usage of seven-element antenna system (radius 30 meters, radiation wave length 20 meters) probability of false identification of no more than 0,1 is achieved in case of deviation of direction of radio radiation arrival from standard one equal to 0,04°. In method for identification of radio radiation, including receipt of radio radiation by means of N antennas and N-channeled receiving device, where N>2, measurement of value of angular spectrum of received radio signals from given direction and comparison to threshold, on basis of results of which arrival of radio radiation from given direction is detected, in accordance to invention, additionally measured are value of angular spectrum, maximal in possible directions, and total energy of received radio signals, after that relation of difference of total energy and maximal value of angular spectrum to difference of total energy and value of angular spectrum of received radio signals from given direction is determined, while received relation is compared to threshold, and value of threshold is determined on basis of provision of required probability of correct identification.

EFFECT: increased efficiency of identification due to stabilization of level of correct identification and decreased level of false identification of radio radiation sources positioned close to given direction, and also when noise intensiveness is unknown.

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Description

The invention relates to radio engineering and can be used in direction finders, radio monitoring systems, radiolocation, radio astronomy.

The need to identify radio emissions in the direction of arrival of radio waves, that is, to establish the fact of the arrival of radio waves not from an arbitrary, but from a given, reference direction, arises in many practical problems. In this case, an objective sign of identification is the direction to the radiation source.

A known method of spatial identification of radio emission, including coherent reception of radio emission using an antenna system and a multi-channel receiving device, measuring the angular spectrum of the received radio signals, the maximum position determines the azimuth and elevation bearings to an identifiable source, and comparing bearings with a given direction, according to which they judge the arrival of radio emissions from this direction. In this case, the measurement of the angular spectrum of the received radio signals is performed with a quantization step set in azimuth and elevation angle by discrete Fourier transform of the received radio signals, subsequent convolution of the radio signal spectra received by different pairs of antennas, two-dimensional spatial Fourier transform of the convolution results and determination of the square of the module of the results of the two-dimensional Fourier transform [Patent RF No. 2158002, G 01 S 3/14, 5/04, 1999].

This method, due to the uncertainty of the comparison threshold in the absence of information about the accuracy of bearing measurements, for example, with an unknown signal amplitude or noise intensity, has a low identification reliability. The disadvantages of the method include significant time costs due to the need to perform a large amount of operations to determine bearings of identifiable sources, especially with a small step of quantizing the range of angles of arrival of radio waves in the horizontal (azimuth) and vertical (elevation) plane.

The closest in technical essence and the achieved result to the proposed one (prototype) is a method of identifying radio emission, including receiving radio emission using N antennas and an N-channel receiving device, where N> 2, measuring the angular spectrum of the received radio signals from a given direction and comparing it with threshold, according to the results of which they judge the arrival of radio emission from a given direction. In this case, the threshold value is set in accordance with the Neumann-Pearson criterion, based on the given probability of false alarm and noise intensity of the receiving device, and the angular spectrum is measured by quadratic amplitude detection of the radio signals of each antenna, phase detection of the pairs of radio signals of various antennas, accumulation of detection results for interval of observation and conversion of accumulated values according to the formula

- комплексный коэффициент направленности n-й антенны в заданном по азимуту θ₀ и углу места β₀ направлении, Е_n - накопленные за время наблюдения результаты квадратичного амплитудного детектирования (энергия радиосигнала принятого n-й антенной),

- накопленные за время наблюдения результаты фазового детектирования (взаимная энергия радиосигналов, принятых n-й и n'-антеннами), * - знак комплексного сопряжения [Репин В.Г., Тартаковский Г.П. Статистический синтез при априорной неопределенности и адаптация информационных систем. М.: Сов. радио, 1977, с.381-388].Where

is the complex directional coefficient of the nth antenna in the direction given in azimuth θ ₀ and elevation angle β ₀ , E _n are the results of quadratic amplitude detection (radio signal energy received by the nth antenna) accumulated during the observation,

- the results of phase detection accumulated during the observation period (mutual energy of radio signals received by the nth and n'-antennas), * - sign of complex conjugation [Repin V.G., Tartakovsky G.P. Statistical synthesis with a priori uncertainty and adaptation of information systems. M .: Sov. Radio 1977, p. 381-388].

Identification decisions in this method are accompanied by errors in assigning sources to a given direction when they are located close to this direction, especially with a high power of interfering radio emissions or with an unknown noise intensity. A contradiction arises: an increase in the level of the interfering signal leads to a decrease in the reliability of identification. In addition, the level (probability) of correct identification (making a decision on the arrival of radio emission from a given direction, if the radiation source is in this direction) is unstable and significantly depends on the noise power, the knowledge of which is necessary to set a threshold.

The technical task of this invention is to increase the identification efficiency by stabilizing the level of correct identification and reducing the level of false identification of radio sources located near a given direction, as well as with an unknown noise intensity.

The problem is achieved in that in the known method of identifying radio emission, which consists in receiving radio emission using N antennas and an N-channel receiving device, where N> 2, measuring the angular spectrum of the received radio signals from a given direction and comparing with a threshold, according to the results of which about the arrival of radio emission from a given direction, additionally measure the maximum in the possible directions value of the angular spectrum and the total energy of the received radio signals, and then determine the ratio difference between the total energy and the maximum value of the angular range to the difference value of the total energy and the angular spectrum of the received radio signal with a predetermined direction, and is compared with a threshold obtained ratio, and the threshold value is determined on the basis of providing the desired probability of correct identification.

A comparative analysis of the claimed solution with the prototype shows that the proposed method differs from the known presence

firstly, new actions on signals and the order of their execution:

measure the maximum value of the angular spectrum;

measure the total energy of the received radio signals;

determine the ratio of the difference in total energy and the maximum value of the angular spectrum to the difference between it and the value of the angular spectrum from a given direction,

secondly, new conditions for the implementation of actions:

the arrival of radio emission from a given direction is judged by comparison with the threshold of the received ratio;

the threshold value is determined on the basis of ensuring the required probability of correct identification.

In the study of other well-known technical solutions in the art, the specified set of features that distinguish the invention from the prototype was not identified.

The proposed technical solution is based on the results of statistical synthesis, as a result of which the need for joint measurement of the angular spectrum values from a given direction (prototype) and the maximum angular spectrum values in the possible directions (analogue), as well as additional measurements of the total energy of the received radio signals, has been established. The difference in the total energy of the received radio signals, the maximum value of the angular spectrum and the values of the angular spectrum from a given direction gives an estimate of the unknown dispersion of noise in the case of respectively the arrival of radio emission from an unknown and a given direction. The decisive statistics in the form of a ratio of differences (variance estimates) turns out to be invariant to the parameters of the signals and noise and tends to 1 when the radio emission arrives from a given direction. This allows you to stabilize the level of correct identification. On the contrary, when radio emission arrives from a different direction from the reference direction, the value of the decisive statistics decreases (to zero), and the greater the higher the level of this radio emission. As a result, the minimum possible probability of false alarm and the “over-resolution” effect are achieved. The physical basis of this effect is the difference in the amplitude-phase relations between the radio signals of the antennas when emitted from different directions. The invariance of the decisive statistics to the parameters of signals and noise is explained by obtaining a specific dispersion ratio in which unknown parameters are mutually compensated. Using these properties in accordance with the proposed new actions on the signals, the order of their implementation and the implementation conditions allows you to remove the contradictions and solve the problem.

Figure 1 shows the structural diagram of a device that implements the proposed method, figure 2 is a variant of the energy meter, figure 3 is a view of the angular spectrum, figure 4 is a histogram of the decisive statistics when the signal-to-noise ratio is 3, 5 is a histogram of decisive statistics with a signal-to-noise ratio of 30; FIG. 6 is a printout of the model of operation of the device in question in the "Mathcad-2000" system.

A device that implements the proposed method contains (Fig. 1) antennas 1.1-1.N, a radio receiver 2, an energy meter 3, a module determination unit 4, a switch 5, a storage device (memory) 6, an angular spectrum analyzer 7, a maximum determination device 8, memory cells (memory cell) 9.1, 9.2, the first accumulating adder (accumulator) 10 and a resolving device 11. The energy meter 3 (figure 2) consists of an analog-to-digital converter (ADC) 12, random access memory 13 multipliers (multiplies) 14.1, 14.2, second and third n accumulating adders 15.1, 15.2.

Antennas 1.1-1.N are connected (Fig. 1) to the inputs of the radio receiver 2 and through its output to the inputs of the energy meter 3, the first output of which is connected to the first input of the switch 5 and directly to its second input through the unit for determining module 4. The output of the switch 5 is connected to the first input of the angular spectrum analyzer 6, the second output of which is connected to the second output of the energy meter 3, and the output of the storage device 6 is connected to the third input. The output of the angular spectrum analyzer 7 is connected to the input of the maximum determining device 8 and the input of the storage cell 9.1 . The device for determining the maximum of 8 output connected to the input of the storage cell 9.2. The second output of the energy meter 3 is connected to the input of the accumulating adder 10. The outputs of the memory cell 9.1, the memory cell 9.2, and the accumulating adder 10 are connected respectively to the first, second, and third inputs of the resolver 11. The analog-to-digital converter 12 of the energy meter 3 is connected with 3 outputs (Fig. 2) with the corresponding inputs of random access memory 13, the first output of which is connected to the first input of the multiplier 14.1, and the second output to the second input of the multiplier 14.1, multiply the first and second input For 14.2, the output of which is connected to the input of the third accumulating adder 15.2, and the output of the multiplier 14.1 is connected to the input of the second accumulating adder 15.1. The outputs of the second and third accumulating adders 15.1, 15.2 are the first and second outputs of the energy meter 3, and the output of the deciding device 11 is the output of the device as a whole.

The number of antennas 1.1, 1.2, ..., 1.N is at least three. The radio receiver 2 is multi-channel, the number of channels is equal to the number of antennas N. The channels are tuned to the frequency of the received signals, have a bandwidth ΔF, consistent with the width of their spectrum.

The energy meter 3 provides a measurement of the energy of the radio signals received by each antenna and the mutual energy of the radio signals of pairs of different antennas. The number of inputs is equal to the number of antennas. The block has two outputs, through the first of which the values of mutual energy are output, through the second output - the values of the energy of the radio signals received by each antenna. A variant of the meter containing quadrature channels with analog detectors and integrators is contained in the book [Repin V.G., Tartakovsky G.P. Statistical synthesis with a priori uncertainty and adaptation of information systems. M .: Sov. radio, 1977, p. 384, Fig. 14.2], and an example of its implementation using digital signal processing is shown in figure 2. The analog-to-digital converter 12 as part of the energy meter 3 is designed to synchronously convert the radio signals of all receive channels to obtain their quadrature components, for example, by counting a pair of values of the sampled radio signals after a quarter of their oscillation period [K. Poberezhsky Digital radio receivers. M., Radio and communications, 1987, p. 64, fig. 3.12 c].

The angular spectrum analyzer 7 is made on the basis of microprocessors and provides the measurement of angular spectrum values by weighted summation of energy and mutual energy with weights determined by the directivity of the antennas, according to the well-known (prototype) formula

комплексный коэффициент направленности n-й антенны, θ, β - возможные углы прихода радиоволн в горизонтальной (азимут) и вертикальной (угол места) плоскости, Е_n - энергия радиосигнала принятого n-й антенной,

- взаимная энергия радиосигналов, принятых n-й и n'-антеннами, звездочка * - знак комплексного сопряжения.Where

the complex directional coefficient of the nth antenna, θ, β are the possible angles of arrival of radio waves in the horizontal (azimuth) and vertical (elevation) plane, E _n is the energy of the radio signal received by the nth antenna,

- mutual energy of radio signals received by the n-th and n'-antennas, asterisk * - sign of complex conjugation.

записывают до начала работы в запоминающее устройство 6 с заданным шагом квантования возможных значений углов прихода радиоволн.Necessary values of complex antenna directivity

write before starting work in the storage device 6 with a given quantization step of possible values of the angles of arrival of radio waves.

Other elements of the device are typical and are implemented using a digital element base.

The principle of operation of the device is as follows.

The radio emission of the transmitter is received using antennas 1.1-1.N and a radio receiving device 2.

In energy meter 3, the energy of a radio signal received by each antenna and the mutual energy of the radio signals of pairs of different antennas, that is, antennas with numbers 1 and 2, 1 and 3 ..., 2 and 3, 2 and 4 ..., etc. are measured. in accordance with the numbers n and n 'in the formula (1). The measurement process is as follows. Using the analog-to-digital Converter 12 synchronously receive complex, in the form of quadrature components, the samples of the radio signal of each antenna with the recording of the results in random access memory 13. The instantaneous value of the radio signal of the nth antenna at time τ = 0, 1, 2, ... (sampling cycle) is a mixture of the received radio signal of a radio emission source and noise

- комплексная огибающая радиосигнала в фазовом центре антенной решетки, θ_и, β_и - направление на источник излучения,

- шум приемного канала.Where

- the complex envelope of the radio signal in the phase center of the antenna array, θ _and , β _and - the direction to the radiation source,

- noise of the receiving channel.

The total number of samples of the radio signal of each antenna is defined as the ratio of the observation time to the sampling period. The sampling frequency in accordance with the Kotelnikov theorem is at least the spectral width of the sampled signal (taking into account the receipt of quadrature components at each count).

радиосигналов, принятых n-й и n' антенной, где n=1, 2,..., N-1, n'=2, 3,..., N и n'>n. Отличие состоит в том, что перемножают отсчеты радиосигналов пар различных антенн. Таким образом, значения энергии и взаимной энергии радиосигналов, принятых антеннами, определяются следующими формулами:The stored values are read in pairs from random access memory 13 for pairs of different combinations of antennas. In the multiplier 14.2, the samples are multiplied by their conjugate values, that is, the squares of the envelope modules of the radio signals of each antenna are formed. The result of the accumulation of these squares of the modules during the observation time (in the adder 15.2) is (up to a constant coefficient) the energy of each of the radio signal antennas received. Similarly, using the multiplier 14.1 and the accumulating adder 15.1, the mutual energies are determined

radio signals received by the nth and n 'antenna, where n = 1, 2, ..., N-1, n' = 2, 3, ..., N and n '> n. The difference is that they multiply the samples of the radio signals of pairs of different antennas. Thus, the values of the energy and mutual energy of the radio signals received by the antennas are determined by the following formulas:

The definition of energy and mutual energy according to formulas (3) corresponds to the accepted [Trakhtman A.M., Trakhtman V.A. Fundamentals of the theory of discrete signals at finite intervals. M .: Sov. Radio, 1975, p. 11].

The total number of measured energy values is equal to the number of antennas N, and the mutual energy is 0.5 · N · (N-1).

, после чего процесс измерения суммарной энергии принятых радиосигналов завершается выдачей результата измерения в решающее устройство 11 (на его третий вход).The measurement results from the outputs of the energy meter 3 are fed to the analyzer of the angular spectrum 7: the values of the mutual energy pass through the first output of the energy meter 3 and the switch 5 to the first input, and the energy values to the second input. In the analyzer of the angular spectrum 7, for each possible value of the angles of arrival of radio waves in accordance with formula (1), the values of the angular spectrum are measured. Simultaneously with the measurement of the angular spectrum, the values of the energy of the radio signals received by each of the antennas accumulated during the observation period, which are generated at the second output of the energy meter 3, are accumulated in the adder 10 along the set of antennas:

, after which the process of measuring the total energy of the received radio signals ends with the issuance of the measurement result to the decisive device 11 (to its third input).

Thus, the measurement of the total energy of the received radio signals includes analog-to-digital conversion to obtain the quadrature components of the radio signals, multiplying the samples of the radio signals by their conjugate values, accumulating the results of the multiplication during the observation time and in the aggregate of antennas.

Among the obtained values of the angular spectrum, the maximum determination device 8 determines the maximum value Z (θ _max , β _max ) in the possible directions of arrival of the radio waves and is recorded in memory cell 9.2, and the measured value of the angular spectrum in the given direction Z (θ ₀ , β ₀ ) is entered into memory cell 9.1 at the time of its receipt from the output of the analyzer of the angular spectrum 7.

Thus, the process of measuring the value of the angular spectrum from a given direction and the maximum value of the angular spectrum includes analog-to-digital conversion to obtain the quadrature components of the radio signals, multiplying the quadrature samples of the radio signals of various pairs of antennas by their conjugate values with time accumulation (measuring the energy and mutual energy of radio signals) , weighted summation of the measured values of energy and mutual energy with weights determined by the antenna directivity coefficients in the rear or the possible direction, and determining the maximum angular spectrum value in the possible directions. The value of the angular spectrum from a given direction in this case is one of the total set of values of the angular spectrum in possible directions.

Note that the weighted summation with weights determined by the directivity of the antennas is carried out once according to the results of previous accumulation. It is fundamentally possible to perform this operation as applied directly to the received radio signals with subsequent accumulation over time of the square of the module of all the results of the weighted summation:

Where

весовые коэффициенты. Данная формула в математическом плане эквивалентна формуле (1). При этом, однако, пропорционально времени наблюдения возрастает число умножений на весовые коэффициенты.

weighting factors. This formula is mathematically equivalent to formula (1). In this case, however, in proportion to the time of observation, the number of multiplications by weight coefficients increases.

причем всегда правая часть примерного равенства больше либо равна левой. Тогда измерение максимального значения углового спектра достигается путем накопления по совокупности пар антенн модулей взаимной энергии, суммирования удвоенного результата этого накопления и суммарной энергии принятых радиосигналов с последующей нормировкой полученной суммы на число антенн, то есть по формулеIn particular cases of using identical non-directional antennas, for example, vertical vibrators, it is proposed to measure the maximum value of the angular spectrum without resorting to quantization and calculation of all its values. The modules of the directivity of such antennas are equal to 1. Then, in the region of the maximum of the angular spectrum, an approximation of the form

moreover, always the right side of the approximate equality is greater than or equal to the left. Then the measurement of the maximum value of the angular spectrum is achieved by accumulating, by the aggregate of the pairs of antennas, modules of mutual energy, summing the doubled result of this accumulation and the total energy of the received radio signals, followed by normalizing the resulting amount to the number of antennas, i.e., by the formula

после их образования в блоке 4 определения модуля и реализуется измерение максимального значения углового спектра в соответствии с формулой (4) при значениях комплексных коэффициентов направленности антенн, равных единице.The implementation in this device of this embodiment of the operation of measuring the maximum, in possible directions, values of the angular spectrum differs from the above general case as follows. In the storage device 6 are entered the values of the complex directivity of the antennas for a given direction of identification and one when determining the maximum angular spectrum. In the analyzer of the angular spectrum 7, the measurement is carried out in two stages (at two points): the values of the angular spectrum in a given direction and the maximum value. At the first stage, the results of measuring the mutual energy enter the analyzer of the angular spectrum 7 through the second input of the switch 5, and the measurement is as described previously using the values of the complex directivity of the antennas for a given direction. At the second stage, analysis of the mutual energy modules is transmitted through the first input of the switch 5

after their formation, in the module determination block 4, the maximum value of the angular spectrum is measured in accordance with formula (4) for the values of the complex antenna directivity coefficients equal to unity.

According to the results of the measurements in the deciding device 11, the difference in the total energy of the received radio signals and the maximum value of the angular spectrum, the difference in the total energy of the received radio signals and the value of the angular spectrum from a given direction, as well as the ratio of these differences with the formation of decision statistics of the following form are determined

At the final stage, the ratio of differences is compared with the threshold

If the threshold h is exceeded, a decision is made on the arrival of radio emission from a given (reference) direction, otherwise, on the arrival of radio emission from a direction other than the reference. The result of the decision in the form of a logical unit (zero) is output to the device.

The angular spectrum characterizes the energy distribution of the received radio signals over the possible angles of arrival of radio waves. Moreover, the following relation holds: Z (θ _max , β _max ) ≤E. Equality is achieved when receiving radio emission from a given direction. Consequently, the angular spectrum has a maximum in the direction of the source of radio emission. An example of the angular spectrum in the azimuthal plane and the polar coordinate system for N = 7 antennas is shown in Fig.3.

разрешается в пользу значения решающей статистики, равного 1. Напротив, при приходе радиоизлучения с иного от заданного направления значение решающей статистики падает (до нуля) по причине уменьшения энергии, принимаемой с заданного направления. Данные положения подтверждаются гистограммами решающей статистики фиг.4, 5, полученными при отношении сигнал-шум (амплитуды сигнала к среднему квадратичному значению шума), равном 3 и 30 соответственно. Гистограммные числа К(Λ) даны по результатам обработки 1000 экспериментов. Сплошной линией показаны результаты при приходе радиоизлучения с заданного направления, а пунктирной - при отличии пеленга от заданного направления на 4°. Видно, что решающие статистики инвариантны к изменению отношения сигнал-шум, очевидны и существенные различия статистических свойств решающих статистик при приеме сигналов с заданного и отличного от него направления. Последнее свойство служит основой принятия решения при идентификации.The difference in the total energy, the maximum value of the angular spectrum and its value from a given direction gives an estimate of the unknown dispersion of noise in the case of respectively the arrival of radio emission from an unknown and a given direction. Decisive statistics in the form of a ratio of differences (variance estimates) are invariant to the parameters of signals and noise. Uncertainty arising upon arrival of radio waves from a given direction

resolved in favor of a decisive statistic value of 1. On the contrary, when radio emission arrives from a different direction, the decisive statistic decreases (to zero) due to a decrease in energy received from a given direction. These positions are confirmed by histograms of the decisive statistics of FIGS. 4, 5 obtained with a signal-to-noise ratio (signal amplitude to mean square noise value) equal to 3 and 30, respectively. The histogram numbers K (Λ) are given according to the results of processing 1000 experiments. The solid line shows the results when radio emission arrives from a given direction, and the dashed line shows the results when the bearing differs from the given direction by 4 °. It can be seen that the decisive statistics are invariant to a change in the signal-to-noise ratio, and significant differences in the statistical properties of the decisive statistics when receiving signals from a given and different direction are obvious. The last property serves as the basis for decision making during identification.

, где i - мнимая единица. Принимался сигнал с частотной модуляцией тоном 1 кГц, девиацией частоты 5 кГц приемным устройством с шириной полосы пропускания 25 кГц при частоте дискретизации аналого-цифрового преобразования 25 кГц. Время наблюдения 320 мкс (восемь отсчетов АЦП). Эталонное значение азимута равно 135°, а угла места 40°. На фиг.6 приведена распечатка модели работы рассматриваемого устройства в системе "Mathcad-2000". В пункте 1 модели (исходные данные) указаны регулируемые параметры антенной системы, системы обработки, сигналов и шумов.The illustrations of FIGS. 3-5 are shown for the following conditions. Antennas (N = 7) are located on a circle, at the same mutual distance. One of the antennas is oriented from the center of the circle to the north and has the number n = 1. Numbering of other antennas and azimuth report clockwise with increasing numbers. The radius of the antenna system is R = 30 m, the radiation wavelength is λ = 20 m. The complex antenna directivity coefficients are determined by the formula

where i is the imaginary unit. A signal with a frequency modulation of 1 kHz tone and a frequency deviation of 5 kHz was received by a receiver with a bandwidth of 25 kHz at a sampling frequency of the analog-to-digital conversion of 25 kHz. Observation time 320 μs (eight samples of the ADC). The reference azimuth is 135 ° and the elevation angle is 40 °. Figure 6 shows a printout of the model of operation of the device in question in the system "Mathcad-2000". Paragraph 1 of the model (initial data) indicates the adjustable parameters of the antenna system, processing system, signals and noise.

In accordance with the results of a statistical analysis of the obtained experimental data, the decisive statistics (4) has a beta distribution

where Γ (·) is the gamma function.

In the case of the arrival of radio waves from a given direction, the shape parameters of this distribution α, β are determined only by the number of antennas and the number W of uncorrelated samples

The number of uncorrelated readings is equal to the product of the observation time and the width of the radiation spectrum (passband of the receiving device).

The threshold value is determined on the basis of a given probability P of correct identification, that is, a decision is made about the arrival of radio emission from a given direction, if the radio emission really comes from this direction. The threshold calculation is performed according to the formula

where qbeta (1-P, α, β) is the function inverse to beta function (7) of argument (1-P).

Thus, the threshold value does not depend on the noise power and is determined by the given probability of correct identification P, the number of antennas N and the number of uncorrelated samples of the signal during the observation time W. The probability of false identification (making decisions about the arrival of radio emission from a given direction, when in reality the direction to the source otherwise) is a function of a large number of parameters of signals, noise and antenna system.

The proposed method provides an increase in identification efficiency by stabilizing the level of correct identification and reducing the level of false identification of radio sources located near a given direction, as well as with an unknown noise intensity. For the above conditions for receiving radio emission using seven antennas against a background of noise of unknown intensity at a fixed level of correct identification P = 0.9 and a signal-to-noise ratio of 3, 30, 300, the probability of false identification of not more than 0.1 is achieved when the direction deviates the arrival of radio emission from a reference equal to 4 °, respectively; 0.4 ° and 0.04 °. In the prototype method, a similar one is possible when detuning beyond the main lobe of the angular spectrum, that is, 30 or more degrees (see Fig. 3), while the noise intensity must be known to ensure setting the threshold.

Claims (1)

A method for identifying radio emission, including receiving radio emission using N antennas and an N-channel receiving device, where N> 2, measuring the angular spectrum of received radio signals from a given direction and comparing with a threshold, based on which the radio emission from a given direction is judged, characterized in that additionally measure the maximum angular spectrum value in possible directions and the total energy of the received radio signals, after which the ratio of the difference of the total energy and max the angular spectrum to the difference between the total energy and the angular spectrum of the received radio signals from a given direction, and the ratio is compared with the threshold, and the threshold value is determined based on ensuring the required probability of correct identification.

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