RU2326402C1 - Method of measurement of radial speed of air target in the mode of frequency tuning from pulse to pulse - Google Patents

Abstract

FIELD: radio location.

SUBSTANCE: accidental law of probing frequency alteration is formed algorithmically from linear - step law of frequency alteration in pulse signals burst. Used range of waves is centimeter with frequency tuning within 150 MHz. Number of used signals in burst is equal to 2^k , where k=6...8. The burst duration should not exceed interval of air target turn angular correlation. Speed is measured during duration of one burst by method of distant portrait complex vector entropy calculation, which is received from frequency characteristic, which is rephrased with complex multipliers, which consider searching of all possible radial speeds of object movement with discretization pitch dV.

EFFECT: high accuracy of measurement and high noise immunity independently from shape, dimensions and geometric structure of target.

3 dwg

Description

The invention relates to the field of radar and is intended to measure the radial speed of an object when using the mode of tuning the carrier frequency from pulse to pulse according to a random law that excludes the negative impact of interference-frequency interference.

There is a method of determining the radial velocity of a target by differentiating ranges when using signals with any law of changing the carrier frequency from pulse to pulse, which consists in the fact that they emit pulsed sounding signals, receive signals reflected from the target, lower the frequency of the received signals to an intermediate one, amplify the received signals by power, convert them into video pulses, compare the received and reference (expected) signals, form an error signal that carries information about the magnitude and sign of disagreement ning, form a control voltage, the change of which repeats the change in the delay time (range), by differentiating the control voltage, a voltage proportional to the radial velocity of the target is obtained [1].

The disadvantage of this method is the low accuracy of speed measurement, due to the fact that range measurement errors, which reach tens of meters in modern radar stations (radars), distort the estimates of the target radial velocity calculation.

попарных произведений комплексно-сопряженных отсчетов отраженных сигналов одной частоты в смежных периодах повторения по формулеThere is another method of measuring radial velocity when using multi-frequency signals [2], which includes emitting multi-frequency signals consisting of two frequency components, receiving signals reflected from the target by two frequency channels of the radar, lowering the frequency of the received signals to intermediate, amplifying the received signals, converting the received signals to video frequency using two quadrature phase detectors, converting the quadrature components of the signals into digital form using analog-to-digital conversion users and conducting algorithmic processing with them in a digital computer. During algorithmic processing, in each k-th frequency channel, the complex sum is found

pairwise products of complex conjugate samples of reflected signals of the same frequency in adjacent repetition periods according to the formula

where the symbol * means the operation of complex pairing;

k is the number of the frequency channel, and k = 1, 2;

j is the number of the repetition period of the multi-frequency signal.

найденных сумм

которые являются доплеровскими сдвигами фаз сигнала за период повторения сигналов одинаковой частоты Т, вычисляют разность Δφ полученных фазовых аргументов φ^(k) сумм в двух, отличающихся частотой излучения, каналахThen, phase arguments are determined in each frequency channel.

amounts found

which are Doppler phase shifts of the signal during the repetition period of signals of the same frequency T, calculate the difference Δφ of the obtained phase arguments φ ^{(k) of the} sums in two channels differing in the frequency of radiation

Δφ = φ ⁽¹⁾ -φ ⁽²⁾ ,

цели по формулеwhere φ ⁽¹⁾ and φ ⁽²⁾ are the Doppler phase shifts of the reflected signal during the repetition period T of single-frequency signals in the first and second channels, respectively. Further, the ambiguity associated with the possibility of obtaining the Δφ value of a different sign is eliminated, and then the radial velocity estimate is calculated from the phase difference Δφ

goals by formula

where c is the propagation velocity of electromagnetic waves; T is the value of the pulse repetition period of the same frequency (the period is the same in both frequency channels); f ⁽¹⁾ and f ⁽²⁾ are the values of the sounding frequencies in the first and second channel, respectively.

The disadvantage of this method is the inability to measure the speed of the target in the conditions of application of interference-oriented interference in frequency. The use of a single-frequency or two-frequency signal with a regular frequency change creates favorable conditions for determining the radiation frequency used and for setting powerful interference at the detected frequency in the following repetition periods. Under such conditions, none of the known methods [1, 2] will not provide a reliable estimate of the radial velocity, as well as other parameters of the target.

It is known that the use of pulsed signals with a change in the carrier frequency from pulse to pulse according to a random (and even pseudorandom) law leads to an increase in the noise immunity of the radar system [3], since effective impact interference can only be set in the next sounding period with respect to the period used for determine (identify) the frequency of radiation. The random law of frequency change excludes the setting of effective powerful impact interference, and the use of obstruction in the entire used frequency range reduces its power in proportion to the increase in the tuning range compared to the impact interference frequency band.

The method [2] can be extended to the case of pairwise use of signals of N frequencies [4]. But in this case, it is necessary to increase the number of processing channels, which complicates the design of the radar. However, even in this case, it is assumed that the signals of the same frequency are repeated for their summation according to the method [2]. And this inevitably leads to the use of targeted interference by the enemy and loss of purpose.

Thus, a reliable way to eliminate the negative impact of impact interference is to use signals with a tuning of the carrier frequency from pulse to pulse according to a random law. However, for such signals, a method for measuring the radial velocity of the target is unknown. The specified radiation mode can be used to construct radar images of air targets by the method [5], the algorithms of which require accurate knowledge of the radial velocity of the target. The methods for estimating the radial velocity were not considered in [5].

The objective of the invention is the provision of measuring the radial velocity followed by the angular coordinates and the distance of the air target in the mode of tuning the carrier frequency from pulse to pulse according to a random law that excludes the use of adversary aimed at frequency interference.

To solve this problem, it is proposed for a time Δt, limited by the interval of angular correlation of the rotation of the air target T _yk , amounting to no more than 5 ms [6, 7], to emit a packet of 2 ^k pulse signals with frequency tuning according to a random law, where k - an integer taking a value from 6 to 8. It is more convenient to take the number of pulse signals equal to 2 ^k , since in this case, the processing can use fast Fourier transform algorithms, which can significantly reduce the amount of calculations [3].

определяется по формулеIn the random access memory, a sequence of frequency values used in the FH pack is formed, from f ₀ to f ₀ + F _per , where f ₀ is the main carrier frequency of the probe signal of the centimeter range, F _per = 150 MHz is the range in which the frequency is tuned from pulse to pulse in increments of Δf = F _per / (N-1), where N is the number of frequencies used. Then the radiation frequency numbers are distributed according to a random law, in which the radiation time t _n from the beginning of the burst for a pulse at the n-th frequency f ₀ + nΔf, where n is the number of the used frequency

determined by the formula

- порядковый номер излучения импульса на n-й частоте f₀+nΔf, принимающий значение от 1 до N, единожды повторяющееся в пределах пачки СПЧ. Например, если в 15-м периоде излучен импульс на 7-й частоте, то

при n=7. Порядок использования частот запоминается для последующей расстановки принятых сигналов в порядке линейного увеличения частоты. Величина Т_и выбирается, исходя из требования обеспечения однозначности отсчетов по доплеровской частоте во всем диапазоне возможных радиальных скоростей цели [8], что в символьном виде выражается неравенствомwhere T _and is the pulse repetition period inside the packet;

- serial number of the pulse radiation at the nth frequency f ₀ + nΔf, taking a value from 1 to N, repeating itself once within the FH bundle. For example, if in the 15th period a pulse is emitted at the 7th frequency, then

for n = 7. The frequency usage order is remembered for the subsequent arrangement of the received signals in the order of a linear increase in frequency. The value of T _and is selected based on the requirement of ensuring the unambiguity of the samples at the Doppler frequency in the entire range of possible radial velocities of the target [8], which in symbolic form is expressed by the inequality

F _and > F _{d max} ,

- частота повторения импульсов внутри пачки;Where

- pulse repetition rate inside the packet;

F _{d max} = 2V _{p max} (f ₀ + F _per ) / c - the maximum possible Doppler frequency of the target;

V _{p max} - the maximum possible radial velocity of the target.

It is further proposed to receive signals reflected from the target at different frequencies f ₀ + nΔf + F _{d n} , where F _{d n} is the Doppler frequency addition of the reflected signal at the nth frequency due to the radial speed of the target, then it is proposed to lower the frequency of the received signals to an intermediate f _pr + F _{d n} , where f _CR is the value of the intermediate frequency, while taking into account the value of the additive nΔf used when emitting a signal at the n-th frequency f ₀ + nΔf so that the frequency difference f _{pr n} of the signal received at the n-th frequency f ₀ + nΔf + F _{d n} and the local oscillator signal (f ₀ -f _pr) + nΔf always determined Referring only to the intermediate frequency value f _etc. and the corresponding value of the Doppler additives F _{d n}

f _{pr n} = (f ₀ + nΔf + F _{d n} ) - [(f ₀ -f _pr ) + nΔf] = f _pr + F _{d n} .

Then, using quadrature phase detectors [8, 9], it is necessary to extract the quadrature components of the received signals, convert the quadrature components to digital using analog-to-digital converters, and convert each signal reflected at the nth frequency into a complex form of the form

- амплитуда отраженного на n-й частоте сигнала;

- фаза отраженного на n-й частоте сигнала;Where

- the amplitude of the signal reflected at the nth frequency;

- phase of the signal reflected at the nth frequency;

и

- значения квадратурных составляющих принятого сигнала на n-й частоте.

and

- the values of the quadrature components of the received signal at the nth frequency.

отраженного сигнала на n-й частоте, при этом принятые сигналы внутри вектора G будут расставлены в порядке линейно-ступенчатого изменения частоты. После этого надо формировать двумерную матрицу D данных из N строк и Z=2V_{p max}/dV+1 столбцов, где число 2 определяет возможность измерения положительных и отрицательных радиальных скоростей (при приближении или удалении объекта), V_{p max} - максимально возможная радиальная скорость цели, выбираемая заблаговременно, dV - интервал дискретизации (шаг изменения) радиальной скорости, определяющий точность измерения радиальной скорости. В элемент n-й строки z-го столбца матрицы D следует записывать комплексную величину

, рассчитанную по формулеThen it is proposed to form a vector G from N elements, write the complex value to the nth element of the vector G

the reflected signal at the nth frequency, while the received signals inside the vector G will be arranged in the order of a linear-step change in frequency. After this, it is necessary to form a two-dimensional matrix D of data from N rows and Z = 2V _{p max} / dV + 1 columns, where the number 2 determines the possibility of measuring positive and negative radial velocities (when approaching or moving away an object), V _{p max} is the maximum possible radial velocity targets selected in advance, dV - sampling interval (step of change) of the radial velocity, which determines the accuracy of the radial velocity measurement. In the element of the nth row of the zth column of the matrix D, write the complex quantity

calculated by the formula

- комплексная величина n-го элемента вектора G.Where

is the complex value of the nth element of G.

It is further proposed by performing the inverse fast Fourier transform with complex data vectors of each column of the matrix D to obtain the matrix D1, then find the maximum value of the modulus of the complex signal in the matrix D1 and divide the complex values of all elements of the matrix D1 by this value, i.e. normalize the elements of the matrix D1, and then - calculate the value of the entropy of the data H _z [10] for each z-th column of the matrix D1 according to the formula

по формулеAt the final stage, it is proposed to find the column number z _{min H} corresponding to the lowest entropy value H _{z min} , with which to determine the estimate of the radial velocity of the target

according to the formula

and take this estimate as the measured value of the radial speed of the air target.

The choice of the interval value of the angular correlation of the rotation of an air target of not more than 5 ms is explained as follows. The rate of change of the plane’s angle during yaw and random rolls is 1 ... 2 ° / s or 0.0175 ... 0.035 rad / s [6]. The angle correlation interval T _yk is determined by the formula [7]

- угловая скорость поворота цели; L_⊥ - поперечный размер цели.where λ is the wavelength;

- angular velocity of rotation of the target; L _⊥ - the transverse size of the target.

The smallest interval of angular correlation in the centimeter wavelength range (λ = 3 cm) will be obtained when observing the largest air target (L _⊥ = 70 m), having a maximum angular velocity of yaw of 2 ° / s. Under these conditions, the interval of angular correlation is T _yk = 6.14 ms. To ensure that the interval T _u exceeds the duration of the FH bundle, it is proposed to limit the duration of the pack (Δt) to 5 ms.

It is advisable to choose the sampling interval dV equal to 0.1 m / s, since at Δt = 5 ms, λ = 3 cm and a signal-to-noise ratio q = 15 ... 30 dB at the output of the processing system, the potential accuracy (mean square error) of the radial measurement velocity σ _v will be

- разрешающая способность по скорости [8].Where

- resolution in speed [8].

The essence of the method of measuring the radial speed of an air target when using signals with frequency tuning from pulse to pulse is as follows.

When emitting signals with frequency tuning from pulse to pulse according to a regular deterministic law and receiving reflected signals, the nth term obtained from complex samples of received signals of a frequency response (frequency response) of a target rotating at a fixed range is determined by the formula [11, 12]:

where K is the coefficient determined by the properties of the radar receiver;

m is the serial number of the diffuser;

M - the number of scatterers on the target glider;

σ _m is the effective reflective area [13] of the m-th diffuser;

R _{m ||} - the distance from the reference range point to the m-th diffuser along the coordinate, relative to the line of sight of the target;

R _m⊥ is the distance from the line of sight of the target to the m-th diffuser in the transverse coordinate;

ψ _m is the phase value due to the reflection of the pulse signal from the m-th diffuser.

An air target always rotates at a certain angular speed. However, a packet of signals with frequency tuning is emitted during a time limited by the interval of angular correlation T _UK . Within this interval, the target does not have time to change its angle so that the phase response of the received packet of reflected signals changes significantly. The distance from the reference range point to the m-th diffuser within T _yk in the absence of the radial velocity of the target will be determined only by the longitudinal coordinate R _{m ||} . Expression (1) is simplified:

Carrying out the inverse Fourier transform with the frequency response of a fixed target leads to the formation of an impulse response or coherent long-range portrait (DL) of the target, in which each m-th diffuser on the target surface corresponds to a well-defined impulse response [11, 12, 14]. The amplitude of the m-th impulse response is proportional to the square root of the effective reflecting area of the m-th scatterer, and the relative position of the responses is uniquely determined by the actual arrangement of the scatterers on the target surface along the line of sight. The expressions for coherent DLP targets are known and presented in [15].

With a linear change in the frequency and movement of the target without changing the angle, which is ensured by the choice of time for the emission of the HF pack no more than 5 ms, the n-th term of the generated frequency response will be described as follows:

where V _p is the radial velocity of the target.

Since the phase of the signal associated with the radial movement of the target does not depend on the number of the diffuser, it can be taken out of the sum sign:

Thus, each n-th term of the frequency response in the case of a target moving with a radial velocity V _p will have a phase addition proportional to the square of the pulse number, the frequency tuning step, the radial velocity of the target, the repetition period T _, and the carrier frequency f ₀ .

In the case of an unknown radial velocity, the phase additives in the frequency response will change according to an unknown quadratic law. Even in this case, after performing the inverse Fourier transform with the frequency response, the generated DL will be distorted and shifted along the range axis. In the case of using the random law of frequency tuning, the change in phase components due to the radial movement of the target will be random in nature, i.e. the phase addition will have a uniform distribution in the range from 0 to 2π, which is an analog of phase noise. Expression (4) in this case takes the form

Such phase chaos in the parameters of the formed frequency response will lead to the formation of a DL, in which the complex amplitudes will also be distributed randomly due to blurry responses from m-x scatterers. Destruction and blurring of the DL is a consequence of the violation of the coherence of the adopted implementation, which lies precisely in the phase distribution of the reflected signals when the frequency changes. The best coherence will be at a constant position of the target relative to the radar. In the presence of a radial velocity, coherence is violated, and it is impossible to obtain informative DL without rephasing.

Thus, when using the random law of frequency tuning, each frequency response sample will have a random phase addition, depending on the number of the pulse at the nth frequency, the order and step of frequency tuning, and also the radial velocity of the target. To form a true DLP of a target, it is necessary to eliminate phase incursions that depend on the listed factors [11, 16]. Since the order of using frequencies and the frequency tuning step are known, in order to eliminate negative phase incursions that distort the structure of the formed DL, it is only necessary to know the target speed.

ЧХ цели на множительIf the radial velocity of the target V _p were known, then to eliminate the phase distortions caused by the presence of radial motion, it would be necessary to multiply each nth term before performing the inverse Fourier transform

CH multiplier goals

However, measuring or estimating the radial velocity of the target V _p is the task of the proposed method, i.e. the value of V _p is unknown. Therefore, to compensate for a random phase change in the elements of the frequency response, it is necessary to use the method of selecting the value of V _p . When enumerating all possible values of the radial velocity from -V _{p max} to + V _{p max,} in one of the cases the best compensation of phase distortions associated with the radial movement of the target will occur, and as a result of the reverse phase Fourier transform, the informative DL will be formed. The geometrical design of the target (the number of scatterers on its surface and the distance between them) and the type of DLP are also unknown. As a criterion for determining the maximum coincidence of the true radial velocity of the target with a variable step dV in the range from -V _{p max} to + V _{p max the} estimated value of the radial velocity of the target, it is advisable to use the minimum entropy of the system [10]. That is, to determine the maximum coincidence of the true radial velocity of the target with one of its values used for phasing the vectors in the columns of the matrix D (let's call it the estimated value of the radial velocity), it is advisable to use the method of calculating the entropy of the system.

By presenting the impulse response (DLP) in the form of a system and normalizing it, we can calculate the entropy Н of this system for all values of the velocity V _p used in the rephasing of the frequency response by the formula

As is known, entropy is a measure of uncertainty and decreases if the uncertainty of the system decreases. It is also known that entropy is maximum when all states of the system are equally probable. But if in the theory of information the entropy of the system is maximum with equal probability of states, then with respect to the complex vector of DLP, the entropy of the data will be maximum with a random and uniform distribution of the complex amplitudes of the reflected signals by the numbers of the elements of DLP. This situation is observed if the true value of the radial velocity does not coincide with one of its values used for phasing the vectors in the columns of the matrix D, since this does not compensate for phase incursions associated with moving the target, which means that the conditions for the formation of an informative DL are violated. The long-range portrait in this case is a vector with randomly distributed amplitudes (Fig. 1). Such a distribution of complex amplitudes in unphased DLP is an analog of a random noise process. So the entropy of the vector in this case should tend to the maximum.

It should be noted that long-range portraits blurred by phase noise will have the property of stationarity, i.e. constancy of numerical characteristics extracted from vectors of their complex amplitudes. Therefore, the entropy of the vast majority of DL vectors that make up the matrix D1 will be approximately the same and dependent on the degree of uniformity of the distribution of random complex amplitudes in long-range portraits.

(другими словами, при совпадении предполагаемого и истинного значений радиальной скорости цели), указанная стационарность будет отсутствовать вследствие появления в ДлП импульсных откликов от реальных рассеивателей и уменьшения среднего уровня шума в виду отсутствия фазового хаоса в ЧХ. В этом случае произойдет наилучшая компенсация фазовых искажений, связанных с движением цели. Следовательно, будет сформирован наиболее информативный ДлП, внешний вид которого сильно отличается от шума (фиг.2). Заметим, что случай совпадения предполагаемого и истинного значений скорости цели соответствует ситуации, когда объект неподвижен.However, in some DLPs, the matrices D1, which turn out to be correctly phased using complex factors

(in other words, if the assumed and true values of the radial velocity of the target coincide), this stationarity will be absent due to the appearance of pulsed responses from real scatterers in the DLP and a decrease in the average noise level due to the absence of phase chaos in the frequency response. In this case, the best compensation for phase distortions associated with the movement of the target. Therefore, the most informative DLP will be formed, the appearance of which is very different from noise (Fig. 2). Note that the case of coincidence of the assumed and true values of the target’s speed corresponds to the situation when the object is stationary.

In this case, the measure of vector uncertainty decreases, and therefore the entropy decreases. The entropy of phased DLP is always less than the entropy of unphased DLP. With the exact coincidence of the assumed and true values of the radial velocity, the entropy is minimal.

A variant of the dependence of the magnitude of the entropy of the vector of the long-range portrait on the expected value of the speed is shown in Fig.3. The graph is obtained by computer simulation. The estimate of the radial velocity in this example was 176.1 m / s with a true radial velocity of the object of 176 m / s. When conducting 1000 calculations by the claimed method, the error in measuring the radial velocity was not more than 0.4 m / s with a signal-to-noise ratio of 16 dB at the output of the processing system, which indicates the operability of the method and high accuracy of measuring the speed.

It should be noted that this method is independent of the size and geometric design of the target (the number of diffusers on its surface). This is explained by the following. Each target, depending on its geometric design, has its own DLP. The structure and appearance of DLP targets are a priori unknown. The main feature of correctly phased DLP is the unsteadiness of the distribution of complex amplitudes in its elements. In unphased DLP, the distribution of complex amplitudes is an analog of a random noise process (Fig. 1). Therefore, no matter how many impulse responses from the diffusers are present in the portrait. The main thing is the fact of localization and growth of their amplitude during coherent processing against a background of noise.

The proposed method is easy to implement and has the following advantages: high noise immunity due to frequency tuning from pulse to pulse according to a random law, eliminating the negative influence of interference-aiming in frequency, independence from the size and geometric design of the target (the number of scatterers on its surface), speed and high accuracy velocity measurements, as well as the possibility of obtaining the target's DLP simultaneously with the measurement of its radial velocity. The proposed method can find application in problems of radar measurements, including in the selection of targets of a certain speed, as well as in tasks of recognizing targets from them by radar images [5, 11, 12].

BIBLIOGRAPHY

1. Okhrimenko A.E. Basics of radar and electronic warfare. Part 1. Basics of radar. - M .: Military Publishing, 1983. - P.387 (analogue).

2. Patent 2166772 (RF) of 05/10/2001, MKI ⁷ G01S 13/58. Detector-meter of multi-frequency signals. Popov D.I., Belokrylov A.G. Application No. 2000105563/09. Priority March 6, 2000 (prototype).

3. Radar systems of multifunctional aircraft. T.1. Radar - the information basis of the fighting of multifunctional aircraft. Systems and algorithms for primary processing of radar signals. / Ed. Kanaschenkova A.I. and Merkulova V.I. - M.: Radio Engineering, 2006. - 656 p.

4. Popov D.I., Belokrylov A.G. Synthesis of detector-meters of multi-frequency signals. University News. Radio electronics, 2001. No. 11, - p. 33-40.

5. Patent 2234110 (RF), IPC ⁷ G01S 13/89. BI 2004, No. 22. A method of constructing a two-dimensional radar image of an air target. / Mitrofanov DG, Bortovik VV and etc.

6. Grigorin-Ryabov V.V. Radar devices. - M .: Owls. Radio, 1970 .-- 680 p.

7. Barton D.K., Ward G.R. Handbook of radar measurements. Per. from English / Ed. Weisbane M.M. - M .: Owls. Radio, 1976.- 392 p.

8. Handbook of radar. / Ed. Skolnik M.I. Per. from English - M .: Owls. radio, 1967.

9. Handbook of the basics of radar technology. / Ed. Druzhinina V.V. - M .: Military Publishing House, 1967 .-- 768 p.

10. Wentzel E.S. Probability theory. M .: Higher. school, 2001 .-- 575 s.

11. Mitrofanov D.G. A comprehensive adaptive method for constructing radar images in dual-purpose control systems. Theory and control systems. 2006, No. 1, pp. 101-118.

12. Mitrofanov D.G., Silaev N.V. An adaptive multi-frequency method for constructing a radar image of a fluctuating air target. Radio engineering. 2002, No. 1, p. 53-60.

13. Finkelstein M.I. Basics of radar. M .: Radio and communications, 1983 .-- 536 p.

14. Manukyan A.A. Determination of the coordinates of local inhomogeneities on the surface of an object from a multi-frequency amplitude-phase backscattering diagram in the presence of phase distortions. Radio engineering and electronics. 1994, No. 1, pp. 81-91.

15. Mitrofanov D.G., Safonov A.V. The use of wavelet analysis to maintain the structure of long-range portraits of aerial targets with an increase in noise level. Electromagnetic waves and electronic systems. 2005, No. 9. p. 19-24.

16. Mitrofanov D.G. The formation of a two-dimensional radar image of the target with trajectory flight instabilities. Radio engineering and electronics. RAS, 2002, No. 7, p. 852-859.

Claims (1)

A method for measuring the radial speed of an air target in the frequency-from-pulse to pulse-frequency adjustment mode, which consists in the fact that using a radar station for a time interval Δt a packet of pulse signals is emitted with tuning of the carrier frequency, pulse signals reflected from the target at n-th frequencies are received, where n is the frequency number of the pulse signal, reduce the frequency of the received pulse signals to an intermediate one, and use quadrature phase detectors to isolate the quadrature components of the received pulse signals signals, convert the quadrature components into digital form using analog-to-digital converters, convert each pulse signal reflected at the nth frequency into a complex form of the form

, Where

- the amplitude of the pulse signal reflected at the nth frequency;

- phase of the pulse signal reflected at the nth frequency;

and

- the values of the quadrature components of the received pulse signal at the nth frequency, characterized in that the number of pulse signals equal to the number of used radiation frequencies in the packet of pulse signals with frequency tuning is chosen equal to 2 ^k , where k is an integer taking a value from 6 to 8, the time Δt for radiation of a burst of pulse signals with frequency tuning is chosen no more than the interval of angular correlation T _y rotation of the air target, amounting to 5 ms, is used when emitting pulses with frequency tuning with the radiative law of frequency variation, for which a sequence of frequency values is used in the random access memory used in a packet of pulse signals with frequency tuning from f ₀ to f ₀ + F _per with a step Δf = F _per / (N-1), where f ₀ - the main carrier frequency of the pulse probe signal of the centimeter range, F _per = 150 MHz — the range in which the frequency is tuned from pulse to pulse, N is the number of frequencies used, the frequency numbers of the radiation are distributed according to a random law, in which the radiation time t _n pulse per n-th frequency f ₀ + nΔf is determined by the formula

, where T _and is the pulse repetition period inside the packet, selected on the basis of the requirement to ensure the uniqueness of the samples at the Doppler frequency in the entire range of possible radial velocities of the target;

- the serial number of the pulse at the n-th frequency, taking a value from 1 to N, repeating itself once within a burst of pulse signals with frequency tuning, remember the order of use when emitting frequencies, when lowering the frequency of the received pulse signals to an intermediate, take into account the value of the addition nΔf used for emission of a pulsed signal at n-th frequency f ₀ + nΔf, that the difference in frequency of the received n-th pulse signal frequency f ₀ + nΔf + _{f, DN,} where _DN: f -doplerovskaya frequency additive reflected pulse signal at n-th hour OTE due to the radial velocity of the target and the local oscillator signal (f ₀ -f _pr) + nΔf always determined only by the value of the intermediate frequency f and corresponding value _ave Doppler additives _DN: F, form G vector of N elements is recorded in n-th element of the vector G complex meaning

of the converted pulse signal reflected at the nth frequency, form a two-dimensional matrix D of data from N rows and Z = 2V _{p max} / dV + 1 columns, where V _{p max} is the maximum possible radial velocity of the target, chosen in advance, dV is the sampling interval of the radial velocity , which determines the accuracy of measuring the radial velocity, write in the element of the nth row of the zth column of the matrix D the complex quantity

calculated by the formula

, Where

- the complex value of the converted reflected at the n-th frequency of the pulse signal recorded in the n-th element of the vector G; z is the column number of the matrix D, get the matrix D1 by performing the inverse fast Fourier transform with complex data vectors of each column of the matrix D, find the maximum value of the modulus of the complex signal in the matrix D1 and divide the complex values of all elements of the matrix D1 by this value, calculate the data entropy H _z for each z-th column of the matrix D1 by the formula

, find the column number z _{min H} corresponding to the lowest entropy value H _{z min} , determine the target radial velocity estimate by the formula

and take this estimate as the measured value of the radial velocity of the target.

Images