RU2496118C2 - Method of identifying radio signals of controlled object and determining position of source - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: method involves preliminary determination of a working area, an object region therein, receiving radio signals at receiving points using direction-finding antennae and a multi-channel receiving device. For each receiving point, noise level distribution in the working area is determined, for which energy of received radio signals is measured, converted to a spatial spectrum which is subtracted from the measured energy. The average geometric noise level distribution and minimum values thereof in and outside the object region are determined, the minimum values are compared, results of which are used to identify radio signals and the position of the source is determined as the position of the minimum in the object region. Conversion to a spatial spectrum is carried out by compensating for phase incursion, taking into account distance from the direction-finding antennae to sources, subsequent summation of the converted radio signals, quadratic detection of the resultant radio signal and dividing the number of direction-finding antennae. The working area is defined in form of a circle with the centre at the geometric centre of the object and is quantised, based on the given accuracy of determining the position of the source of the controlled object, on an Archimedean spiral law.

EFFECT: high accuracy of identification and high accuracy of determining the position of a radiator.

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Description

The invention relates to radio engineering and can be used in radio monitoring systems for identifying and determining the location of sources of unauthorized radio emissions within a controlled object (space zone).

A known method of detecting sources of electromagnetic radiation within the controlled zone, including receiving radio signals outside the controlled zone and within or in the immediate vicinity of it, measuring and comparing the levels of received signals, emitting radiation whose levels within or in the immediate vicinity of the controlled zone are equal to or exceed measured levels outside this zone. [one. RF patent No. 2099870, cl. H04B 1/46, G01S 11/00, publ. 1997].

The disadvantage of this method is the inability to determine the location of the emitter in a controlled area.

Of the known closest to the proposed technical essence and the achieved effect is (prototype) a method for identifying sources of electromagnetic radiation of an object with a mobile direction finder, including preliminary determination, by uniform quantization in the Cartesian coordinate system, of the working area, as the area of energy availability of radio emissions, in it the area of the object , receiving radio signals and direction finding using direction finding antennas forming an antenna array, and a multi-channel receiving device mobi direction finder at reception points located on different sides of the object, determining for each receiving point the angular boundaries of the object’s area, comparing the direction finding results with these boundaries, if they get into which the radiation is identified as belonging to the object, in this case, lines of bearings are laid , and the location of the radiation source is estimated from the intersections of the lines of bearings. [2. Ashikhmin A.V., Zhukov A.A., Kozmin V.A. etc. Detection of sources of electromagnetic waves in objects using a mobile complex of radio direction finding and control. "Special equipment", special. issue, January 2003, p. 61-73].

The disadvantages of this method are as follows. With large direction-finding errors, the method provides low identification accuracy and location accuracy. In this case, the bearing lines extend beyond the area of the object, which is accompanied by a transmission of radiation. Instrumental accuracy is also reduced due to uniform quantization of the working area. At high levels of interference and direction-finding errors that are characteristic of the conditions of an industrial city that are high and unknown at various points of reception, the operation of setting the identification boundaries of an object becomes completely uncertain. An artificial increase in the area of an object in excess of its true size leads to an increase in the level of false alarms; uncertainty arises in estimating the location of the emitter.

An object of the invention is to increase the reliability of identification, increase the accuracy of determining the location of the emitter, providing identification at high and unknown levels of interference.

, где x_ν, y_ν - абсцисса и ордината ν-го кванта в декартовой системе координат, ν=0,1,…,V-1 - номер кванта, i - мнимая единица, Δ - заданная точность определения местоположения, V=R_s/Δ - число квантов, R_s - радиус рабочей зоны.The stated technical problem is solved due to the fact that in the known method of identifying radio signals of a controlled object and determining the location of the source, including preliminary determination of the working area, the area of the object in it, the reception of radio signals at reception points using direction finding antennas and a multi-channel receiving device, according to the invention, for each receiving point, the distribution of the level of interference in the working area is estimated, for which the energy of the received radio signals is measured, and converted into space This spectrum, which is subtracted from the measured energy, then determines the geometric mean of the distributions of the interference level, its minima in the region of the object and outside the object, the values of the minima are compared, as a result of which the radio signals are identified and the source location is determined as the position of the minimum in the region of the object, while the transformation in the spatial spectrum is performed by compensating the calculated, taking into account the distances from direction-finding antennas to sources, phase incursions of the received radio signals, subsequent summation converted radio signals, quadratic detection of the total radio signal and dividing by the number of direction-finding antennas, and the working area is determined in the form of a circle centered at the geometric center of the object and quantized, based on the given accuracy of determining the location of the source of the controlled object, according to the law of the Archimedes spiral, while the complex coordinates of quanta as places of possible radiation, determined by the formula $${\dot{z}}_{\nu }=y_{\nu }+i\cdot x_{\nu }=\nu \cdot \Delta \cdot e^{i\cdot \mathrm{one}.737\cdot \nu }$$

, where x _ν , y _ν is the abscissa and ordinate of the νth quantum in the Cartesian coordinate system, ν = 0,1, ..., V-1 is the quantum number, i is the imaginary unit, Δ is the specified location accuracy, V = R _s / Δ is the number of quanta, R _s is the radius of the working area.

These advantages, as well as features of the present invention are illustrated by a variant of its implementation with reference to the accompanying figures.

Figure 1 is a structural diagram of a radio monitoring system for implementing the inventive method;

Figure 2 is a structural diagram of a processing and identification unit;

Figure 3 is a quantized working area (in small dots) with locations of reception points (in bold dots) and an object area (bounded by a circle);

Figure 4 is a graph of the distribution surface of the average interference level;

5 is a histogram of crucial statistics;

6 - dependence of the probabilities of correct identification and false alarm from the bearing error;

Fig.7 - dependence of the linear error of determining the location of the emitter of the object from the bearing error.

The solution of the technical problem posed is based on the results of statistical synthesis under conditions of uncertainty of interference levels and consists in the transition from the attribute space of bearings adopted in the closest analogue [2] to the attribute space in the form of a distribution of the average interference level in the working area. For this, the distribution of the interference level is evaluated at each reception point, then averaged over the set of reception points, determining the geometric mean.

When evaluating the distribution of the interference level, the energy of the received radio signals is measured, converted into a spatial spectrum, which is subtracted from the measured energy. The spatial spectrum characterizes the distribution of radiation energy in the working area, is formed by compensating for the calculated phase incursions of the received radio signals, then summing the converted radio signals over the set of direction-finding antennas of the receiving point, quadratic detection of the total radio signal and dividing by the number of direction-finding antennas. The calculated phase incursions are determined based on the distances from direction-finding antennas to possible radiation sites.

The proposed procedure for determining the spatial spectrum is based on taking into account the dependence of the source field strength on the distance to it. In particular, the phase incursion is proportional to distance. In the closest analogue [2], this information is taken into account indirectly during direction finding. A more complete consideration of this factor provides an increase in the efficiency of solving the problem of identification and location.

After subtracting the spatial spectrum from the energy at the point of the true coordinates of the source, the noise component remains in the resulting difference. For other points in space there will be a noise composition and an uncompensated remainder of radiation, that is, with a level higher than at the point of true coordinates. Regardless of the intensity of noise (interference), the global minimum of distribution is located in the vicinity of the true coordinates of the source. When radiation comes from an object, the minimum distribution in the region of the object is predominantly less than the minimum determined in the region of space outside the object. The reverse situation is when a third-party source emits.

This allows, by determining and comparing the minima of the average level of interference in the area and outside the object, to make the most plausible decisions, statistical stability of identification is achieved with an unknown noise level in a wide range of its variation.

The definition of the average level of interference in the form of a geometric mean, as a root of degree N from a product of n [3. Bronstein I.N., Semendyaev K.A. A reference book in mathematics for engineers and students of technical colleges. - M., Nauka, 1986, p.139], the distribution of all points of reception is achieved by taking into account the unevenness of measurements, inversely proportional to the estimated level of interference, ultimately, improves the accuracy of positioning.

An additional increase in accuracy due to the transition from adopted in the prototype [2] uniform quantization to uneven quantization of the working area. The error in determining coordinates increases with distance from the center of the working area. Quantization according to the law of the spiral of Archimedes achieves an increase in the density of quantization points in the region of the object, inversely proportional to the distance from the center of the working area.

Thus, taking into account the dependence of the source field strength on the distance to it, the transition to the characteristic space in the form of a distribution of the average level of interference in the working area and its uneven quantization, in accordance with the proposed new actions on the signals, the conditions and the order of their implementation, allows us to solve the problem : increase the accuracy of identification, increase the accuracy of determining the location of the emitter, to ensure identification with unknown levels of interference.

The claimed method can be implemented using the appropriate radio monitoring system.

The radio monitoring system (figure 1) that implements the proposed method contains N≥1 reception points 1.1-1.N, each of which includes M≥3 direction-finding antennas 2.1-2.M, radio receiver 3, switch 4 and data transmission equipment 5 , a control and processing center 6, containing data transmission equipment 7, a processing and identification unit 8, a control panel 9, an indicator 10. Antennas 2.1-2.M through the inputs of a 1-M radio receiver, its 1-M outputs are connected to inputs 1-M switch 4, the output of which is connected to the first input of data transmission equipment 5 points reception 1.1, the first output of which is connected to input 0 of the radio receiving device 3. The second input of data transmission equipment 5 is the input of reception point 1.1, the output of which is the second output of this equipment. The inputs 1-N of the data transmission equipment 7 of the control and processing center 6 are connected to the outputs of the receiving points 1.1-1.N, respectively, and its outputs of the same name to their inputs. The data transmission equipment 7 of the control and processing center 6 is connected through 0 output, 1 input of the processing and identification unit 8 of its 1-3 outputs to indicator 10 through its 1-3 inputs. The output of the control panel 9 is connected to 0 input of the data transmission equipment 7 and 2 to the input of the processing and identification unit 8.

The processing and identification unit 8 contains (Fig. 2) means for evaluating the distribution of the interference level 11, comprising an energy meter 12, including a series-connected detector 13 and an accumulating adder 14, a multiplier 15, a phase advance calculator 16, connected in series by the input to the output of the multiplier 15 accumulating adder 17, detector 18, divider 19, through the second input a subtractor 20 and an averaging device 21, a memory (memory) 22 of the antenna coordinates, connected by an output to 3 input of the phase advance calculator 16, the second input is a cat It is connected to the output of the working area memory 23, the storage area 24 of the object is connected through 1 input of the matching circuit 25, the inverter 26 to the input 2 of the first minimum determinant 27.1, the second 27.2 minimum determinant, the first output of which is connected to 2 input of the comparison circuit 28, to 1 input which is connected 1 output of the first determinant of the minimum 27.1, the first input of which and the first input of the second determinant of the minimum 27.2 are connected to the output of the averaging device 21. The output of the accumulating adder 14 of the energy meter 12 is connected to 1 input of the subtractor 21. The output of the memory 23 working zone is connected to the input 2 of the matching circuit 25. The input 1 of the noise level estimator 11 is the first input of the processing and identification unit 8, connected to the first input of the multiplier 15 and the input of the detector 13 of the energy meter 12, the input 2 of this means is the second input of the processing and identification unit 8 is connected to 1 input of the phase advance calculator 16. Outputs 1-3 of the processing and identification unit 8 are, respectively, 2 output of the first determinant of minimum 27.1, output of the comparison circuit 28 and output 2 of the second determinant of minimum 27.2.

If possible, the reception points 1.1-1.N it is advisable to place on the outside of the object near its contour, as shown in figure 3, their number is not less than one, N≥1, but with increasing N, the identification efficiency increases.

Direction finding antennas 2.1-2.M identical, omnidirectional in the horizontal plane, are placed equidistant on the circumference of a given one, in order to ensure unambiguous direction finding, radius. Thus, a direction-finding antenna system (equidistant array) is formed. The number of antennas M≥3. The numbering of antennas m = 1,2, ..., M is performed from the reference direction, for example, the direction to the North, clockwise. The antenna with the number m = 1 is oriented relative to the center in the reference direction.

The radio receiver 3 has a number of channels equal to the number of antennas, performs filtering and synchronous conversion of direction-finding antenna signals with a digital representation in the form of quadrature components (complex amplitudes), for example, according to the option given in [4. Poberezhsky K. S. Digital radio receivers. M., Radio and communications, 1987, pp. 67-68, Fig. 3.14].

Switch 4 provides sequential information retrieval from the outputs of the 1-M radio receiving device 3 supplied to its inputs of the same name, followed by transmission using data transmission equipment 5 through its input 1 and output 2 to the control and processing center 6 to input 1 multi-channel, according to the number reception points, data transmission equipment 7. Next, the information received by the data transmission equipment 7 is transmitted through output 0 to the processing and identification unit 8 to its first input. Similarly and alternately for other points of reception.

The frequency of tuning the radio receiving device 3 of the receiving point 1.1 (similarly for other receiving points) is controlled by the input and receiving device 3 from the control panel 9 through 0 input and 1 output of the data transmission equipment 7 of the control and processing center 6, input 2 and output 1 of the transmission equipment data 5 points of reception 1.1. At the same time, the frequency value from the control panel is fed to input 2 of the processing and identification unit 8, where it is used to calculate the phase incursions.

The indicator 10 displays the identification results received at inputs 1-3 from the outputs of the same name of the processing and identification unit 8.

The processing and identification unit 8 is made FIG. 2 based on a digital element base. The multiplier 15 of this block provides the multiplication of the complex value (at the first input) to the complex conjugate (at the second input). Before the direct operation of the radio monitoring system begins, the coordinates are recorded in the storage devices (antennas): the antennas of the receiving points in the memory 22, the quanta of the working area in the memory 23, the quanta of the object area in the memory 24.

The working area is defined as the area of energy availability of radio emissions in the form of a circle centered in the geometric center of the object. In an industrial city, the radius of the working area is 0.5-3.0 km. An example of such a working area with a radius of R _s = 500 m is shown by small dots in figure 3. The area of the space occupied by the object is an internal subregion of the working area, bounded by a circle with a radius of 100 m.

The working area is quantized, based on the specified accuracy of determining the location of the source of the controlled object, according to the law of the Archimedes spiral [3, p.128], while the complex coordinates of quanta, as places of possible radiation, are determined by the formula

$${\dot{z}}_{\nu }=y_{\nu }+i\cdot x_{\nu }=\nu \cdot \Delta \cdot e^{i\cdot \mathrm{one}.737\cdot \nu },(\mathrm{one})$$

where the point above the quantity indicates its complex nature, x _ν , y _ν - abscissa and ordinate of the v-th quantum in the Cartesian coordinate system, ν = 0,1, ..., V-1 - quantum number, i - imaginary unit, Δ - given location accuracy, V = R _s / Δ is the number of quanta, R _s is the radius of the working area.

The coefficient 1.737 in the exponent, which determines the speed of the angular rotation of the spiral vector, is selected from the condition of ensuring the equidistance of the nearest quanta.

An example of a working zone quantized by formula (1) is shown in FIG. 3 for the parameters: Δ = 1.134 m, R _s = 500 m, V = 441. In the figure and hereinafter, the indication of the numbers of quanta is omitted to simplify the recording.

In accordance with figure 3, the quantization density increases in the center of the working area, that is, exactly where the object is located and the maximum potential accuracy of determining the location of the emitter is achieved.

All coordinates quantized by formula (1) are entered in the memory of 23 quanta of the working area, and in the memory of 24 quanta of the object’s area, the coordinates of the quanta that fall into the object’s area, that is, remote from the center, are points with coordinates (0, 0), the working area is not more than 100 m.

, где n=1,2,…,N - номер пункта приема, m=1,2,…,M - номер антенны этого пункта приема, X_n,m,Y_n,m - абсцисса и ордината координат антенн в декартовой системе, удобно определить как сумму координат непосредственно пункта приема $${\dot{Z}}_n^{\text{'}}$$

и относительных координат антенн $${\dot{Z}}_m^{"}$$

(относительно центра пункта приема):Reception point antenna coordinates $${\dot{Z}}_{n,m}=Y_{n,m}+i\cdot X_{n,m}$$

, where n = 1,2, ..., N is the number of the receiving point, m = 1,2, ..., M is the number of the antenna of this receiving point, X _{n, m} , Y _{n, m} are the abscissa and the ordinate of the antenna coordinates in the Cartesian system , it is convenient to define as the sum of the coordinates of the reception point itself $${\dot{Z}}_n^{\text{'}\text{'}}$$

and relative antenna coordinates $${\dot{Z}}_m^{"}$$

(relative to the center of the reception point):

$${\dot{Z}}_{n,m}={\dot{Z}}_n^{\text{'}\text{'}}+{\dot{Z}}_m^{"}.(2)$$

The coordinates of the points of reception can be determined using radio navigation devices, and the relative coordinates of the antennas are calculated by the formula

$${\dot{Z}}_m^{\text{'}\text{'}\text{'}\text{'}}=R\cdot e^{i\cdot \frac{2\cdot \pi }{M}\cdot (m-\mathrm{one})},(3)$$

where R is the radius of the direction-finding antenna system (array).

The coordinates of the antennas of the receiving points obtained in this way are stored in the memory 22 of the coordinates of the antennas.

The principle of subsequent operation of the radio monitoring system is as follows.

подвергают обработке в блоке обработки и идентификации 8. Истинные значения комплексных амплитуд зависят от расстояний антенн с координатами $${\dot{Z}}_{n,m}$$

до источника излучения с координатами $$\dot{z}$$

.Received antennas 2.1-2.M receiving points 1.1-1.N radio signals in the form of complex amplitudes $${\dot{S}}_{m,n}$$

subjected to processing in the processing and identification unit 8. The true values of the complex amplitudes depend on the distances of the antennas with coordinates $${\dot{Z}}_{n,m}$$

to the radiation source with coordinates $$\dot{z}$$

.

$$r_{n,m}(x,y)=\left|\dot{z}-{\dot{Z}}_{n,m}\right|.(\mathrm{four})$$

These complex amplitudes are determined by the formula

where u _n , ϕ _n is the amplitude and initial phase of the radio signal in the center of the direction-finding antenna system, λ = c / f is the radiation wavelength, c = 3 · 10 ⁸ m / s is the speed of light, f is the radiation frequency, π = 3, 1428 ...

The value in the exponent in (5) of the form

$${\varphi }_{n,m}(\dot{z})=-i\cdot \frac{2\cdot \pi }{\lambda }\cdot r_{n,m}(\dot{z})(6)$$

there is a phase shift of the radio signal due to its delay in propagation.

, начальные фазы ϕ_n, амплитуды u_n неизвестны.Emitter coordinates $$\dot{z}$$

, the initial phases ϕ _n , the amplitudes u _{n are} unknown.

During radio wave propagation and reception, the radio signals are distorted by noise and interference, so that the complex amplitudes of the received radio signals are a mixture

$${\dot{S}}_{n,m}={\dot{a}}_{n,m}+{\dot{\xi }}_{n,m},(7)$$

- шумы приема с неизвестным, в общем случае различным в точках приема уровнем.Where $${\dot{\xi }}_{n,m}$$

- reception noise with an unknown, generally different level at the points of reception.

In the processing and identification unit 8, the following transformations are performed.

For each receiving point in the tool 11 (figure 2) evaluate the distribution of the level of interference in the working area. To do this, using a meter 12 measure the energy of the received radio signals. The radio signal received by each antenna of the receiving point, received at the first input of the means for estimating the distribution of the interference level, is quadratically detected in the detector 13 and summed over the totality of antennas in the accumulating adder 14, the output of which receives the measured energy of the radio signals of each receiving point

$$E_n={\displaystyle \sum _{m=\mathrm{one}}^M{\left|{\dot{S}}_{n,m}\right|}^2.(8)}$$

. Необходимые при этом координаты точек рабочей зоны $$\dot{z}$$

и антенн $${\dot{Z}}_{n,m}$$

поступают из запоминающих устройств соответственно 23 и 22 по второму и третьему входу вычислителя 16, а значение частоты - по его первому входу (со второго входа средства оценки распределения уровня помех 11). Непосредственно преобразование в пространственный спектр выполняют путем умножения принятых радиосигналов, поступающих на первый вход умножителя 15, на комплексный фазовращающий множитель, поступающий на его второй вход с вычислителя 16. После чего, преобразованные радиосигналы суммируют по совокупности пеленгаторных антенн в накапливающем сумматоре 17, квадратично детектируют детектором 18 и делят в делителе 19 на число пеленгаторных антенн. В совокупности реализуется преобразование в пространственный спектр, описываемое следующим аналитическим соотношением:Simultaneously with the measurement of energy, the received radio signals are converted into a spatial spectrum. In this case, in the calculator of phase 16 incursions, taking into account the distances (4) from direction-finding antennas to sources, phase incursions (6) are calculated, with their representation as a complex factor $${\dot{w}}_{n,m}(\dot{z})=e^{i\cdot {\varphi }_{n,m}(\dot{z})}$$

. The necessary coordinates of the points of the working area $$\dot{z}$$

and antennas $${\dot{Z}}_{n,m}$$

come from the storage devices 23 and 22, respectively, at the second and third input of the calculator 16, and the frequency value is received at its first input (from the second input of the means for estimating the distribution of the interference level 11). Direct conversion to the spatial spectrum is performed by multiplying the received radio signals supplied to the first input of the multiplier 15 by a complex phase-shifting factor supplied to its second input from the calculator 16. After that, the converted radio signals are summed over the entire range of direction-finding antennas in the accumulating adder 17 and are quadratically detected by the detector 18 and is divided in the divider 19 by the number of direction-finding antennas. Together, the transformation into the spatial spectrum is realized, which is described by the following analytical relationship:

в показателе экспоненты стоит знак минус (результат умножения на комплексно сопряженную величину в умножителе 15), то набеги фаз принятых радиосигналов $${\dot{S}}_{m,n}$$

в точке истинных координат действительно компенсируются, происходит когерентное сложение и образуется максимум пространственного спектра.Since during the calculated phase incursion $${\varphi }_{n,m}(\dot{z})$$

in the exponent, there is a minus sign (the result of multiplication by the complex conjugate in the multiplier 15), then the phase incursions of the received radio signals $${\dot{S}}_{m,n}$$

at the point of true coordinates, they are really compensated, coherent addition occurs and the maximum of the spatial spectrum is formed.

Based on the measured energy (8) and spatial spectrum (9), subtracting the second from the first in the subtractor 20 estimates the distribution of the noise level at each point of the working area

$$G_n(\dot{z})=E_n-G_n(\dot{z}).(\mathrm{one}0)$$

The resulting distribution is averaged over the totality of all points of reception, for which the geometric mean is determined in the averaging device 21

$$\gamma (\dot{z})=\sqrt[N]{{\displaystyle \prod _{n=\mathrm{one}}^N{G}_n(\dot{z})}}.(\mathrm{one}\mathrm{one})$$

A typical distribution of the average interference level (12) when emitted from the center of the object with the placement of reception points according to FIG. 3 is shown in FIG. 4. This distribution has a minimum at the point of true source coordinates. For subsequent identification, the minima are determined, among all the quanta of the space of the corresponding minimization region, the distribution in the region outside the object, the determinant of the minimum 27.1, and in the region of the object, the determinant of the minimum 27.2. An indication of whether the distribution values of the average level of interference coming from the averaging device 21 belong to, the minimization areas are carried out by signals at the inputs 2 of the control of determinants 27.1, 27.2. These signals are generated by the matching circuit 25. The single level corresponds to the coincidence of the coordinates of the point of the working area of the charger 23 with the coordinates of the points of the object area of the charger 24. At the moment of coincidence, the corresponding value of the average noise level is taken into account when minimizing the minimum in 27.2. The determinant 27.1 functions logically opposite, the control signals for which are changed by the inverter 26.

From the first outputs of the minimum determinants 27.1, 27.2 to the first and second inputs of the comparison circuit 28, the minimum values of the distribution of the average level of interference in the area outside the object and in the area of the object are received. These values are compared and if the first value (outside the object) exceeds the second, the radio signals are identified, a decision is made on whether the radio signals belong to the object, and a logical unit is issued at the second output of the comparison circuit 28. The location of the source is defined as the position of the minimum in the area of the object and from the output 2 of the determinant 27.2, the corresponding coordinates are sent to the output 3 of the processing and identification unit 8 and then to the input of the same indicator 10 to display the location of the emitter. If the comparison condition is not met, a logical zero is generated in circuit 28 and the location of the third-party source (if necessary) is displayed, the coordinates of which are received from the second output of the determinant 27.1 at the first output of the processing and identification unit 8 and then to the first input of the indicator 10.

Figure 5 shows the histograms of the decisive statistics W (g), where g is the ratio of the minima of the distribution of the average noise level in the area outside the object and in the area of the object. The circles indicate the data from the emission of third-party sources, the rhombuses when the object is emitted. The distribution of sources is equally probable in the relevant field. The results were obtained from 1000 statistical experiments for the parameters: N = 3, M = 3, R = 0.1 m, λ = 1 m, signal-to-noise ratio 5 (ratio of the amplitude of the radio signal to the mean square value of the Gaussian centered noise at the output of the radio receiver) . The indicated conditions correspond to a rather high mean square error of direction finding error of 15 degrees. It can be seen that, when the object is emitted, the decisive statistics predominantly exceed unity, which allows identification at unknown noise levels by comparing the distribution minimums of the average noise level in the area of the object and in the area outside the object.

The claimed method can be implemented using a mobile direction finder [2]. In this case, use one set of reception center and a control and processing center combined with it.

Identification efficiency is characterized by two indicators: the probability of correct identification (determining whether the radiation belongs to the object, if it really comes from it) and false alarm (determining whether the radiation belongs to the object, if it emits an external source). The dependences of these indicators on the potential root mean square error of direction finding σ are shown in Fig.6, a circle for false alarm F (σ), a rhombus for the correct identification of P (σ).

The potential accuracy (error) of direction finding for the indicated direction-finding system is determined by the known [5. Dzvonkovskaya A.L., Dmitrienko A.N., Kuzmin A.V. Efficiency of measuring signal arrival angles by direction finders based on the maximum likelihood method. - Radio engineering and electronics, 2001, v. 46, No. 10, p. 1242-1247.] By the ratio:

$$\sigma =\sqrt{\frac{2}{M}}\cdot \frac{\lambda }{\rho \cdot 2\cdot \pi \cdot R},(\mathrm{one}2)$$

where ρ is the signal-to-noise ratio.

The potential accuracy (error) (24) depends not only on the noise level (signal-to-noise ratio), but also on the grating radius and the radiation wavelength. Therefore, although the direction finding is not directly performed in the proposed solution, the potential mean square error of direction finding σ, provided by the direction-finding antenna system used, is adopted as a parameter determining the identification efficiency.

In accordance with Fig.6, in a wide range of changes in direction finding error (and interference level), the probability of correct identification is close to unity. The probability of false alarm decreases sharply, by about two orders of magnitude, as the bearing error decreases.

что эквивалентно ответствующему изменению значения минимума в области объекта.When changing the composition and parameters of the radio monitoring system, as well as the radius of the object R _{0, in} order to stabilize the probability of correct identification, the comparison level in scheme 28 should be adjusted by changing its unit value by a coefficient

which is equivalent to the corresponding change in the minimum value in the area of the object.

The linear error Δr (σ) of determining the location of the emitter of the object (the average value of the distance of the estimated location of the emitter from the source) by the proposed method almost linearly increases with increasing direction finding error.

Compared with the closest analogue [2], the proposed solution provides identification at unknown interference levels, an increase in the reliability of identification is achieved, both by stabilizing the probability of correct identification and by reducing the level of false alarm, the accuracy of determining the location of the emitter is increased. In particular, with the same number of quanta, the quantization step of the object region decreases, relative to uniform quantization in the closest analogue, by π · R _s / Δ times, respectively, the instrumental accuracy of determining the location of the emitter of the object increases. This increase in accuracy reaches three orders of magnitude for the adopted parameters of the radio monitoring system.

Claims (1)

A method for identifying radio signals of a monitored object and determining the source location, including preliminary determination of the working area, the area of the object in it, receiving radio signals at reception points using direction finding antennas and a multi-channel receiving device, characterized in that for each reception point the distribution of the level of interference in the working area is estimated why measure the energy of the received radio signals, convert them into a spatial spectrum, which is subtracted from the measured energy, then determine the average then the geometric distribution of the noise level, its minima in the region of the object and outside the object, the values of the minima are compared, as a result of which the radio signals are identified and the location of the source is determined as the position of the minimum in the region of the object, while the conversion to the spatial spectrum is performed by compensation, taking into account the distance from the direction-finding antennas to sources, calculated phase incursions of received radio signals, subsequent summation of converted radio signals, quadratic detection of the total a radio signal and dividing by the number of direction-finding antennas, while the working area is determined in the form of a circle centered in the geometric center of the object and quantized based on the specified accuracy of determining the location of the source of the controlled object, according to the law of Archimedes spiral, while the complex coordinates of quanta as places of possible radiation determine according to the formula $${\dot{z}}_{\nu }=y_{\nu }+i\cdot x_{\nu }=\nu \cdot \Delta \cdot e^{i\cdot \mathrm{one}.737\cdot \nu },$$

where x _ν , y _ν is the abscissa and the ordinate of the νth quantum in the Cartesian coordinate system, ν = 0,1, ..., V-1 is the quantum number, i is the imaginary unit, Δ is the specified location accuracy, V = R _s / Δ is the number of quanta, R _s is the radius of the working area.

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