RU2154840C1 - Device determining parameters of movement of object - Google Patents

Abstract

FIELD: radiolocation, specifically, processes reconstructing trajectory of target in spaced radiolocation. SUBSTANCE: device includes transmitting position and receiving position in point distant from transmitting position. Receiving position has antenna connected to receiver whose output is linked to inputs of unit measuring Doppler frequency and to inputs of unit measuring direction of arrival of interference signal, unit of extrapolation of measured parameters whose one input is linked to output of unit measuring Doppler frequency, whose second input is connected to output of unit measuring direction of arrival of interference signal and whose output is coupled to input of unit computing moment of time of target crossing line of base, unit determining surfaces of position connected with first input to output of unit computing moment of time of target crossing line of base, with second input to output of unit of extrapolation of measured parameters and with output to one of inputs of unit computing trajectory parameters, another input of it being linked to output of unit measuring direction of arrival of interference. In correspondence with invention there are inserted two units: unit determining statistical characteristics of measurement errors of Doppler frequency and direction of arrival of interference signal and unit of final computation of trajectory parameters One input of unit determining statistical characteristics of measurement errors of Doppler frequency and direction of arrival of interference signal is linked to output of unit measuring direction of arrival of interference signal, its second input is connected to output of unit measuring Doppler frequency and its output is connected to one of four inputs of unit of final computation of trajectory parameters, its other three input being separately linked to outputs of unit measuring direction of arrival of interference signal, unit measuring Doppler frequency and unit computing trajectory parameters. Output of unit of final computation of trajectory parameters is output of device. EFFECT: increased precision in location of position of object. 6 dwg

Description

 The invention relates to the field of radar and, in particular, to methods for restoring the trajectory of a target in a spaced radar.

 Various devices are known for determining the motion parameters of an object in diversity radar. One of them serves to implement the method described in [1, p. 321]. The device consists of a pulse signal transmitter and at a distance equal to the length of the base line, the receiving position, remote from it. The receiving position consists of an antenna connected to the receiving device, the output of which is connected to the inputs of two blocks: a block for determining the position surface (surface of equal phases or total distances determined by the sum of the distances from the transmitter to the target and from the target to the receiver) and the block for determining the angular coordinates of the target . The outputs of the units for determining the position surface and determining the angular coordinates of the target are connected to the final unit of the device - the unit for determining the target path. The coordinates of the target in this device are determined in the final unit of the device.

 The target coordinates in this device are located as the intersection point of a straight line drawn from the receiving position at angles measured in the block for determining the angular coordinates of the target with the surface of the target position. The target position surface is determined in the position surface determining unit from the measured difference in the delay time of the pulse reflected from the target and the pulse sounding signals.

 However, in the zone of the presence of the "translucent" effect, that is, near the base line, this difference is small and its determination requires probing with very short pulses. This greatly complicates the generation, subsequent processing of the echo signal and protection against passive interference. In addition, there is a problem of synchronization of the receiving and transmitting positions, the solution of which with a significant separation of the transmitting and receiving positions and the presence of reflections from the underlying surface requires complicating the equipment and increasing its cost.

 Another device implements the method described in [2, p.29-30]. It consists of a transmitter of a monochromatic signal and at a point remote from it at a distance equal to the length of the base line, the receiving position. The receiving position consists of a series-connected antenna, receiver, detector, detecting the interference signal of the beats, a low-pass filter, a unit for determining the time instant of voltage transitions through zero and a unit for calculating trajectory parameters.

 The trajectory parameters of the target in this device are determined by detecting the total signal (the direct signal of the transmitter and the signal of the secondary radiation of the object are summed up), then isolating the interference signal of the beats, measuring the times of transitions of its voltage through zero and calculating the trajectory parameters based on the measurements made. In this device, the parameters of the object’s trajectory — its speed, course, coordinate of the point of intersection of the projection of its trajectory with the baseline — are determined by measuring the durations of several consecutive periods of the interference signal of the beats.

 The disadvantage of devices implemented by this method is the low accuracy of the estimates obtained and the ambiguity in determining these parameters. The first is explained by the fact that near the base line where measurements are taken, position surfaces (surfaces of equal phases or equal total distances) are ellipsoids, strongly elongated along the coordinate axis parallel to the base line. The presence of ambiguity is associated with the symmetry of the position ellipsoids relative to the plane perpendicular to the base line through its middle. In this regard, two different trajectories symmetrical with respect to the mentioned plane generate the same and indistinguishable interference signals of the beats.

 The specified disadvantage deprived of the device that implements the method [3]. A device that implements this method contains a transmitting position emitting a monochromatic signal, and at a point remote from it, a receiving position that receives the probing signal and the secondary radiation signal of the object, extracting from them by detecting the interference beat signal (low frequency signal), measuring the frequency of this signal, for example, by measuring the time moments of its voltage transitions through zero, simultaneously measuring the direction of arrival of the interference signal, for example, single-pulse method according to the ratio of the amplitudes of the interference signal in the partial channels, by the phase method or by scanning the antenna beam to the maximum values of the signal envelope at the output of the low-pass filter [1, p.274-310; 4, p. 388-406], and determining the point in time when the frequency of this signal is zero. According to the measured values, the trajectory parameters are determined as the coordinates of the intersection point of the position surface, determined by the values of the frequency of the interference signal of the beats and the time when the frequency of this signal is zero, and the direction line of arrival of the interference signal.

 The main disadvantage of this device is the inability to determine the location of the target before it crosses the base line.

 In the device [5] this drawback is absent. This device contains a transmitting position and at a point remote from it, a receiving position consisting of an antenna connected to a receiving device (including at least one channel consisting of a serial connection of the receiver, detector and low-pass filter), the output of which is connected to the inputs of the unit measuring the Doppler frequency and the inputs of the unit for measuring the direction of arrival of the interference signal, the unit for extrapolating the measured parameters, one of the inputs of which is connected to the output of the unit for measuring the Doppler Astotics, the second input is with the output of the unit for measuring the direction of arrival of the interference signal, and the output of the unit for extrapolating the measured parameters is connected to the input of the unit for calculating the instant of crossing the target of the base line, the unit for determining the position surface, one of the inputs of which is connected to the output of the unit for calculating the moment of crossing the target base lines, the second input — with the output of the extrapolation unit of the measured parameters, and the output with one of the inputs of the final unit of the device — the block for calculating trajectory parameters, etc. the angular input of which is connected to the output of the unit for measuring the direction of arrival of the interference signal, while the output of the entire device is the output of the block for calculating the trajectory parameters.

 This device is taken as a prototype. The device taken as a prototype is characterized by a significant increase in the error of measuring the distance to the target in the vicinity of the base line, which is associated with a high sensitivity of measurements to deviations of the angular coordinate and deviations of the position surface in the immediate vicinity of the base line, as well as insufficient accuracy of determining the target’s location by Compared to potentially achievable accuracy.

 The proposed device eliminates this drawback. This is achieved by the fact that in the device, taken as a prototype and containing a transmitting position and at a point remote from it, a receiving position consisting of an antenna connected to a receiving device, the output of which is connected to the inputs of the Doppler frequency measuring unit and the inputs of the interference arrival direction measuring unit a signal, an extrapolation unit for the measured parameters, one input of which is connected to the output of the Doppler frequency measuring unit, the second input - with the output of the unit for measuring the direction of arrival of interference the signal, and the output of the extrapolation unit of the measured parameters is connected to the input of the unit for calculating the instant of crossing the target of the base line, the unit for determining the position surface connected by one input to the output of the unit of calculating the moment of time the target intersects the base of the base, and the second to the output of the extrapolating unit of measured parameters , and the output with one of the inputs of the final unit of the device - the unit for calculating the path parameters, the other input of which is connected to the output of the unit for measuring the direction of arrival of the interface of the interference signal, a unit for determining the statistical characteristics of errors in measuring the Doppler frequency and the direction of arrival of the interference signal and a block for the final calculation of trajectory parameters are introduced, and one input of the unit for determining the statistical characteristics of errors in measuring the Doppler frequency and direction of arrival of the interference signal is connected to the output of the unit for measuring the direction of arrival of the interference signal, the second input is with the output of the Doppler frequency measuring unit, and the output is connected to one m of the four inputs of the final calculation of trajectory parameters of the block, the other three inputs of which are connected separately to the outputs of the measurement unit the arrival directions of the interference signal, a Doppler frequency measurement unit trajectory parameters and calculating unit, wherein the output device is output only final calculation of the trajectory of the parameter block.

 The use of new blocks and links has increased the accuracy of determining the location of the target, especially at the moment of crossing the base line. This is achieved through the implementation of additional transformations in the input units over the primary measured parameters (Doppler frequency and the direction of arrival of the interference signal) and a preliminary estimate of the target coordinates obtained in units borrowed from the prototype device.

 Comparison of the proposed technical solution with other well-known sources of patent and scientific and technical documentation shows that they lack technical solutions that allow achieving the technical result set in the invention — determining the location of the target with an accuracy close to that which is potentially achievable throughout the trajectory.

 The stated essence will be clear from the following graphic materials.

In FIG. 1 shows a functional diagram of the inventive device when determining the direction of arrival of the interference signal is carried out by a single-pulse method with two spatial channels. In the drawing, the notation is introduced:
1 - transmitting position;
2 - antenna receiving position (in this case, forms two beams 2.1 and 2.2);
3 - receiver;
4 - detector;
5 - low-pass filter;
6 - block measuring the direction of arrival of the interference signal (α);
7 - unit for measuring Doppler frequency (f _∂ );
8 - extrapolation unit of the measured parameters (dependences of the Doppler frequency and the angular coordinate of the target on time);
9 - unit for calculating the instant of time when the target intersects the base line;
10 - block determining the position surface;
11 - block calculating the path parameters;
12 is a block for determining the statistical characteristics of measurement errors of the Doppler frequency and the direction of arrival of the interference signal;
13 - block final calculation of the trajectory parameters.

 In FIG. 2 is a functional diagram of a prototype device with determining the direction of arrival of the interference signal by a single-pulse method with two spatial channels, where the same ones as in FIG. 1, notation.

вектор, начало которого расположено в точке расположения приемной позиции (O,O), а конец - в точке расположения цели (x, y),

вектор, начало которого расположено в точке расположения передающей позиции (d, O), а конец - в точке расположения цели (x, y),
d - расстояние от передающей позиции до приемной позиции (базовое расстояние);
α - угловая координата цели;

бистатический (двухпозиционный) угол между векторами

x, y - координаты цели;

вектор скорости цели;

проекции вектора скорости цели

на соответствующие координатные оси;
φ - угол наклона траектории цели к линии базы;
x_П - точка пересечения целью линии базы.In FIG. Figure 3 shows the basic geometric relationships for the proposed device, shows the Cartesian coordinate system xOy associated with it and a possible moving target. In FIG. 3 is indicated:
P - transmitting position (located at the point with coordinates (d; O));
Pr - receiving position (located at the point with coordinates (O; O));

a vector whose beginning is located at the location of the receiving position (O, O), and the end is at the location of the target (x, y),

a vector whose beginning is located at the location of the transmitting position (d, O), and the end is at the location of the target (x, y),
d is the distance from the transmitting position to the receiving position (base distance);
α is the angular coordinate of the target;

bistatic (on-off) angle between vectors

x, y - target coordinates;

target speed vector;

projections of the target speed vector

on the corresponding coordinate axes;
φ is the angle of inclination of the target path to the base line;
x _P - the point of intersection of the target line base.

In FIG. 4 - 5 are graphs illustrating the simulation results of the proposed device. The horizontal axis shows the x-coordinate of the target’s movement in relative units to the length of the base line of the system — the distance between the transmitting and receiving positions. The y-axis of the target’s movement is plotted along the vertical axis, also in relative units to the base distance of the system. It is considered that the transmitting position is located at the point with coordinates (d; O), and the receiving position is at the point (O; O)). In FIG. 4 shows a separate implementation of the trajectory, built on the measured values of α, f _∂ and the trajectory parameters calculated in the device (position 2). Position 1 in FIG. 4 and FIG. 5 - the true trajectory of the target in the xOy plane. In FIG. 5 shows the boundaries of the mean-square error regions σ _r calculated from 1000 independent implementations (position 2 in FIG. 4) of the input data for modeling the operation of the device. Reference numeral 3 in FIG. 4 and FIG. 5, similar graphs are indicated, but constructed according to the results of modeling the operation of the prototype device.

In FIG. Figure 6 shows the dependences of the standard errors of the x coordinate normalized to the length of the base line d, depending on the normalized value of the ordinate y of the target, calculated for the same motion path (Fig. 5) with the parameters: x _P / d = 0.425, φ = 60 ^o .

 The solid line shows the mean square errors obtained by modeling the operation of the inventive device for 1000 independent implementations of the input data (position 2 in Fig. 4). The line in the form of short strokes shows similar graphs for the prototype device. A long dashed line shows graphs of potentially achievable mean square errors in determining the coordinates of the target in the same relative units and for the same conditions as the rest of the graphs.

The proposed device with determining the direction of arrival of the interference signal by a single-pulse method with two spatial channels (see Fig. 1) consists of a transmitting position 1 and, at a point remote from the radiation source, a receiving position. The receiving position, in turn, consists of an antenna 2 of the receiving position, which has two outputs, each of which is connected to the input of the serial connection of the receiver 3, detector 4 and the low-pass filter 5. The outputs of the low-pass filter 5 are separately connected to the corresponding inputs of the interference signal arrival direction measuring unit 6 and block 7 measuring the Doppler frequency. The output of the block 7 for measuring the Doppler frequency f _{∂ is} connected in series with the blocks: block 8 for extrapolation of the measured parameters, block 9 for calculating the time of the target crossing the base line, block 10 for determining the position surface, block 11 for calculating the path parameters and block 13 for the final calculation of the path parameters. The other three inputs of the block 13 of the final calculation of the trajectory parameters are separately connected to the output of the block 6 for measuring the direction of arrival of the interference signal, the output of the block 7 for measuring the Doppler frequency and the output of block 12 for determining the statistical characteristics of errors in measuring the Doppler frequency and the direction of arrival of the interference signal, the inputs of which are in turn connected with the outputs of block 6 measuring the direction of arrival of the interference signal and block 7 measuring the Doppler frequency. In this case, the output of the interference signal arrival direction measuring unit 6 is connected to the second input of the measured parameter extrapolation unit 8 and the second input of the trajectory parameter calculation unit 11, and the output of the measured parameter extrapolation unit 8 with the second input of the position surface determining unit 10. The output of block 13 of the final calculation of the trajectory parameters is the output of the entire device.

 The proposed device operates as follows. Assume that the probing signal is continuous (unmodulated), and the receiving antenna 2 has partial channels in the azimuth plane 2.1 and 2.2 (Fig. 1). Under these conditions, the device provides the ability to measure two parameters of the signal reflected from the target: the Doppler frequency by the beat frequency generated by adding the reflected signal from the target and the direct signal of the transmitter (this operation is carried out in block 7 of the Doppler frequency measurement) and the angular coordinate of the target by comparing beating amplitudes with the same Doppler frequency in partial channels (block 6 measuring the direction of arrival of the interference signal).

Consider the possibility of determining the measured values of the Doppler frequency f _∂ (t) and the angular coordinate of the target α (t) of the motion parameters of the target in the inventive device.

 Conventionally, the operation of the entire device can be divided into two stages. On the first of them, a preliminary assessment of the target’s location takes place (carried out in blocks 1–11), and on the second, it is refined in accordance with the maximum likelihood criterion (carried out in blocks 12–13).

где r(t) и r₁(t) - зависимости модулей векторов

движущейся цели от времени (фиг. 3);
R_Σ(t) - суммарное расстояние передатчик - цель - приемник;
λ - длина волны излучения.Briefly explain the main points of finding the initial assessment of the trajectory parameters of the target in blocks 1-11. As is known [1, p. 326; 2, p.30; 6, p. 199], there is the following dependence of the Doppler frequency on the trajectory of the target:

where r (t) and r ₁ (t) are the dependences of the moduli of vectors

moving target from time to time (Fig. 3);
R _Σ (t) - total distance transmitter - target - receiver;
λ is the radiation wavelength.

Integration (1) with knowledge of the corresponding constant allows us to obtain the dependence R _Σ (t). The integration constant is uniquely determined at the time t _P of the target crossing the base line, because at this moment the Doppler frequency and the target azimuth vanish, and the total range is equal to the base of the system (R _Σ (t _p ) = d). Thus, before the target crosses the base line in block 8, the Doppler frequency is extrapolated to approximate the dependence of f _∂ (t) on time and the block in time 9 is determined by the target crossing the base line (for this, the angular coordinate extrapolation can also be used). Then, in block 10, based on (1), the total range is estimated for the current observation moment R _Σ (t). After the target crosses the base line, the estimate R _Σ (t) can be obtained by directly integrating the measured dependence f _∂ (t) from the moment t _P to the current moment of observation of the target.

Легко видеть, что знание дальности до цели позволяет определить как декартовые координаты цели (фиг. 3), так и скорость ее движения при известных значениях дальности для двух разных моментов времени.According to the results of measuring the total range R _Σ (t) and measuring the angular coordinate, the initial estimate of the target’s coordinates (range to the target) can be obtained as the intersection point of the position surface and the beam drawn from the receiving position at the measured angles of arrival of the wave, in accordance with the following expression for range to the target:

It is easy to see that knowing the range to the target allows you to determine both the Cartesian coordinates of the target (Fig. 3) and its speed at known range values for two different points in time.

где T - знак транспонирования;
^ - обозначает оценку измеряемой величины;

оценки в i-й момент времени t₁ = iT, соответствующий i-му интервалу первичных измерений ((i - 1)T, iT),

оценки в текущий момент наблюдения t_n = nT, соответствующий n-му интервалу первичных измерений ((n - 1)T, nT).In more detail, the process of obtaining an initial estimate of the trajectory parameters of the target as a result of the operation of blocks 1-11 is described in [5]. To briefly explain the operation of the device at the second stage (the stage of obtaining a more accurate estimate), we assume that the primary parameters of the interference signal — the Doppler frequency f _∂ and the angular coordinate α — are measured at discrete times at equal time intervals T, and there are n sequential measurements of these the parameters produced in block 7 measuring the Doppler frequency and block 6 measuring the direction of arrival of the interference signal, respectively. For convenience, these primary measurements can be represented as a vector

where T is the transpose sign;
^ - indicates the evaluation of the measured value;

estimates at the i-th moment of time t ₁ = iT, corresponding to the i-th interval of primary measurements ((i - 1) T, iT),

estimates at the current observation moment t _n = nT, corresponding to the n-th interval of primary measurements ((n - 1) T, nT).

где x_n,y_n,V_x= Vcos(φ), V_y= Vsin(φ) - значения декартовых координат цели и скоростей их изменения в момент наблюдения t_n (фиг. 3).When the target moves along a linear trajectory with a constant speed V during the time interval nT, from the moment the measurement t ₁ begins to the moment t _{n is} observed, the trajectory parameters can be completely described by the vector

where x _n , y _n , V _x = Vcos (φ), V _y = Vsin (φ) are the values of the Cartesian coordinates of the target and the rates of their change at the time of observation t _n (Fig. 3).

Маневрирование цели может быть учтено путем ограничения количества пар n измерений первичных параметров, используемых для оценки вектора параметров

Задачей вводимых блоков является наиболее точное определение вектора траекторных параметров

по вектору измерений

Для этого производится уточнение предварительной оценки вектора траекторных параметров в соответствии с оптимальными критериями теории оценивания.The location of the target at any other point in time t _i can be determined by the vector of parameters

Maneuvering the target can be taken into account by limiting the number of pairs of n measurements of primary parameters used to estimate the parameter vector

The task of the input blocks is the most accurate determination of the vector of trajectory parameters

by measurement vector

For this, a preliminary estimate of the vector of trajectory parameters is refined in accordance with the optimal criteria of the theory of estimation.

Здесь m - номер итерации, m = 0,1...;

- начальное приближение, полученное в результате работы предшествующим вновь вводимым блокам (а именно, по результатам работы блоков 2-11 приемной позиции).For example, in the case of using the maximum likelihood method, it is possible to use the following iterative procedure [7, p. 369]:

Here m is the iteration number, m = 0,1 ...;

- the initial approximation obtained as a result of the work of the previous newly entered blocks (namely, according to the results of the operation of blocks 2-11 of the receiving position).

нелинейная векторная функция, определяемая следующими простыми зависимостями, связывающими точные значения измеряемых первичных параметров f_∂1 и α_i с точными значениями траекторных параметров:

прямоугольная [2n x 4] матрица, каждая строка которой - градиент одной из функций

по вектору

V_e - корреляционная матрица ошибок первичных измерений, размером [2n х 2n] (получаемые в блоках 6, 7 оценки угловой координаты и частоты Доплера несмещенные).

nonlinear vector function defined by the following simple dependencies connecting the exact values of the measured primary parameters f _∂1 and α _i with the exact values of the trajectory parameters:

rectangular [2n x 4] matrix, each row of which is a gradient of one of the functions

by vector

V _e - correlation matrix of errors of primary measurements, size [2n x 2n] (obtained in blocks 6, 7 estimates of the angular coordinate and Doppler frequency unbiased).

Поиск оценок среднеквадратических отклонений ошибок измерения доплеровской частоты и угловой координаты, σ_f и σ_α можно производить также как и ранее при экстраполяции первичных измерений (производимой в блоке 8 устройства-прототипа и предлагаемого устройства), используя аппроксимацию измеренных зависимостей доплеровской частоты

и угловой координаты

Для этого можно использовать, как и ранее, то обстоятельство, что изменения частоты Доплера и угловой координаты от времени для типичных целей, обнаруживаемых и сопровождаемых предлагаемым устройством, могут быть с высокой степенью точности аппроксимированы полиномами с небольшим числом коэффициентов.In practice, discrete measurements of primary parameters are carried out through the interval T equal to or greater than the correlation interval of estimates, therefore, the matrix V _e is diagonal and contains the values of σ on the main diagonal $\genfrac{}{}{0ex}{}{\text{2}}{\text{f}}$ , σ $\genfrac{}{}{0ex}{}{\text{2}}{\text{α}}$ - variances of measurement errors of the Doppler frequency and the angular coordinate, assumed to be the same for all time moments i:

The search for estimates of the standard deviations of the errors in measuring the Doppler frequency and the angular coordinate, σ _f and σ _α can be performed as before when extrapolating the primary measurements (performed in block 8 of the prototype device and the proposed device) using an approximation of the measured dependences of the Doppler frequency

and angular coordinates

For this, one can use, as before, the fact that changes in the Doppler frequency and angular coordinate with time for typical targets detected and accompanied by the proposed device can be approximated with a high degree of accuracy by polynomials with a small number of coefficients.

In a polynomial model of parameter measurements, an approximated dependence, for example, for the Doppler frequency, will be presented in the form:
f _{∂, MOD} (t) = c _o + ... + c _m-1 t ^m-1 + c _m t ^m , (10)
where M is the order of the polynomial.

где

n - мерный вектор доплеровской частоты;
n - число измерений, по которым производится аппроксимация,

μ(n) - в данном случае ошибки измерения f_∂. .In the matrix form, equation (10) for several successive instants of time t ₁ , t ₂ , ..., t _n-1 , t _n can be written

Where

n is the dimensional vector of the Doppler frequency;
n is the number of measurements by which the approximation is made,

μ (n) - in this case, measurement errors f _∂ . .

где B=(P_n ^TP_n)^-1P_n ^T.Using (11) and setting n> M, we find optimal estimates of the coefficients of the polynomial model (12) by the least squares criterion [8, p. 238-250]

where B = (P _n ^T P _n ) ^-1 P _n ^T.

в (10), получим зависимость

аппроксимирующую изменение параметров f_∂ и α на отрезке времени [t₁, t_n]:

где

Таким образом, из полученной зависимости (14) вместо исходных измеряемых параметров

определим их сглаженные (аппроксимированные) значения

в дискретные моменты времени t₁, t₂,...,t_n

Аналогичным образом по (10) - (15) определяются сглаженные значения угловой координаты

После определения сглаженных оценок первичных измеряемых параметров значения σ_f, σ_α для (9) можно определять как:

Вычисление оценки

с использованием (6) можно считать завершенным, например, если модуль разности между двумя последовательными оценками абсциссы цели меньше определенной константы:

Таким образом, в каждом из двух парциальных каналов, состоящих из последовательного соединения приемника 3, детектора 4, ФНЧ 5, происходит детектирование и выделение низкочастотного колебания из суммарного сигнала, образуемого за счет интерференции прямого сигнала передатчика 1 и сигнала, отраженного от цели. Далее с выхода параллельных каналов низкочастотное колебание поступает в блок 7 измерения доплеровской частоты и блок 6 измерения направления прихода интерференционного сигнала, в котором при рассматриваемом варианте реализации устройства, угловая координата определяется путем сравнения амплитуд низкочастотного сигнала в каждом из парциальных каналов. По данным, получаемым из блоков 6 измерения направления прихода интерференционного сигнала и блока 7 измерения доплеровской частоты, в блоке 8 экстраполяции измеряемых параметров, блоке 9 вычисления момента времени пересечения целью линии базы, блоке 10 определения поверхности положения и блоке 11 вычисления траекторных параметров происходит, как и в устройстве-прототипе, в соответствии с (1) - (2) вычисление предварительной оценки параметров движения цели

При этом блоки 8-11 могут быть выполнены на основе схем вычитания, делителей, перемножителей, сумматоров (т.е. типовых радиотехнических элементах), аналогично блокам счетно-решающего устройства, схемы вычитания, схемы сравнения амплитуд [1, с.297-300].Substituting the obtained estimates

in (10), we obtain the dependence

approximating change in the parameters f _∂ and α on the time interval [t ₁ , t _n ]:

Where

Thus, from the obtained dependence (14) instead of the initial measured parameters

define their smoothed (approximated) values

at discrete time instants t ₁ , t ₂ , ..., t _n

Similarly, from (10) - (15), the smoothed values of the angular coordinate are determined

After determining the smoothed estimates of the primary measured parameters, the values of σ _f , σ _α for (9) can be determined as:

Grade Calculation

using (6) can be considered complete, for example, if the modulus of the difference between two successive estimates of the abscissa of the target is less than a certain constant:

Thus, in each of the two partial channels, consisting of a serial connection of the receiver 3, detector 4, low-pass filter 5, low-frequency oscillations are detected and extracted from the total signal generated by interference of the direct signal of transmitter 1 and the signal reflected from the target. Further, from the output of the parallel channels, the low-frequency oscillation enters the unit 7 for measuring the Doppler frequency and the unit 6 for measuring the direction of arrival of the interference signal, in which, with the considered embodiment of the device, the angular coordinate is determined by comparing the amplitudes of the low-frequency signal in each of the partial channels. According to the data obtained from blocks 6 for measuring the direction of arrival of the interference signal and block 7 for measuring the Doppler frequency, in block 8 for extrapolation of the measured parameters, block 9 for calculating the instant of time when the target crosses the base line, block 10 for determining the position surface, and block 11 for calculating trajectory parameters, and in the prototype device, in accordance with (1) - (2) calculating a preliminary estimate of the target motion parameters

In this case, blocks 8-11 can be performed on the basis of subtraction schemes, dividers, multipliers, adders (ie typical radio engineering elements), similarly to blocks of a calculating-solving device, subtraction scheme, amplitude comparison circuit [1, p.297-300 ].

Data obtained from blocks 6 for measuring the direction of arrival of the interference signal and block 7 for measuring the Doppler frequency are also sent to block 12 for determining the statistical characteristics of errors in measuring the Doppler frequency and direction of arrival of the interference signal, where the statistical characteristics of the measurement errors of the incoming primary parameters are evaluated (assessment of the elements of the correlation error matrix for measuring primary parameters V _e ). As noted earlier, in practice it is sufficient to determine the variance of the measurement errors of the Doppler frequency and the angular coordinate σ $\genfrac{}{}{0ex}{}{\text{2}}{\text{f}}$ , σ $\genfrac{}{}{0ex}{}{\text{2}}{\text{α}}$ , which is done in block 12 based on formulas (16), (17). Therefore, in block 12 for determining the statistical characteristics of the errors in measuring the Doppler frequency and the direction of arrival of the interference signal, the smoothed values (15) of the primary parameters are first determined by formulas (14), and then by formulas (16), (17) to estimate the standard deviations of the measurement errors of the Doppler frequency and the angular coordinates σ _f and σ _α . With a linear approximation (M = 1, (10)), this block can be performed, for example, on the basis of transversal filters, which are the basic elements for both the extrapolation operation and the procedure for calculating the dispersion of measurements of primary parameters. In general, it can be performed on typical radio engineering elements: subtraction schemes, dividers, multipliers, combiners and delay lines; or implemented programmatically on a special computer. Block 12 for determining the statistical characteristics of measurement errors of the Doppler frequency and the direction of arrival of the interference signal can be performed, for example, similarly to the special calculator block [6, p. 241].

получаемой в блоке 11 вычисления траекторных параметров.The information obtained in the block 11 for calculating the trajectory parameters and the block 12 for determining the statistical characteristics of the errors in measuring the Doppler frequency and the direction of arrival of the interference signal is fed to the final unit of the device — the block 13 for the final calculation of the trajectory parameters. In addition to the data from blocks 11 and 12, data received from the block 6 for measuring the direction of arrival of the interference signal and the block 7 for measuring the Doppler frequency are received in the final block 13. Based on the data received, in block 13 of the final calculation of the trajectory parameters, refinement is made according to (6) of the initial estimation of the target motion parameters

obtained in block 11 calculating the trajectory parameters.

При этом блок 13 конечного вычисления траекторных параметров выполняет функциональные преобразования входного колебания, описываемые в данном случае системой (6). Эти функциональные преобразования также могут быть представлены в виде последовательности операций, состоящей из комбинации простых арифметических действий (сложения, вычитания, умножения и деления), связывающих выходное напряжение с входным сигналом.As the studies showed, the potential accuracy of determining the parameters of the target’s movement is practically achieved using a small number of iterations (6). Therefore, when implementing the block under consideration, it suffices to restrict ourselves to a single solution to the system of equations (6) and determine

In this case, the block 13 of the final calculation of the trajectory parameters performs functional transformations of the input oscillation, which are described in this case by the system (6). These functional transformations can also be represented as a sequence of operations consisting of a combination of simple arithmetic operations (addition, subtraction, multiplication and division) that connect the output voltage to the input signal.

 In the General case, the block 13 of the final calculation of the trajectory parameters can be performed on typical radio engineering elements: subtraction schemes, dividers, multipliers, adders, comparison schemes and delay lines; or implemented programmatically on a special computer.

 The main operations performed in the inventive device and distinguishing from the prototype are as follows: calculating the statistical characteristics of the measurement errors of the Doppler frequency and the angular coordinate, updating the preliminary estimation of the target motion parameters, for example, according to the maximum likelihood criterion.

 The invention will remain unchanged for any implementation of the unit for measuring the direction of arrival of the interference signal. The angle of arrival of the signal reflected from the target can also be measured, for example, by a phase method or by scanning the antenna beam to the maximum values of the signal envelope at the output of the low-pass filter. These possible variants of the device are not shown in the figures.

 Depending on the method used to determine the direction of arrival of the interference signal, the block 6 for measuring the direction of arrival of the interference signal can be performed on the basis of various blocks. For example, with the phase monopulse method for measuring angular coordinates, block 6 can be a phase meter [1, p. 300], when using the amplitude monopulse method, block 6 can be performed based on the amplitude comparison circuit or the subtraction circuit [1, p.297]. If, for example, a subtractor or a phase meter is used as a block 6 for measuring the direction of arrival of the interference signal, the device contains several spatial channels, the output of each of which is fed to the input of the subtractor or phase meter.

 Block 7 measuring the Doppler frequency can be, for example, a low-frequency meter measuring the frequency of an alternating voltage (frequency meter) or is implemented as a unit for determining the moments of voltage transition through zero. Possible ways of implementing new blocks introduced into the device are indicated earlier in the description of the operation of the device.

 The blocks used in the invention can be made on the basis of standard, typical radio engineering elements.

 The effectiveness of the proposed device was evaluated by mathematical modeling. In FIG. Figures 4-6 show the corresponding graphs, made for example by the results of modeling one trajectory. The final (in block 13) determination of coordinates in the considered case was carried out taking into account all primary measurements, starting from the moment of detection and tracking of the target.

The graphs in FIG. 4 - 6 are calculated for a system with parameters d = 40 km, λ = 1 m, T = 1.024 s. The values of the standard errors of the measurement of the primary parameters at all intervals of the primary measurements were taken equal to σ _f = 2 Hz, σ _α = 0.5 ^° , the target velocity V = 200 m / s.

 The analysis of the accuracy of determining the coordinates of the target of the proposed device under other conditions showed that the accuracy of measuring the distance to the target increases compared with the prototype device almost throughout the trajectory. When the system works with the above parameters (taken for modeling), the accuracy of determining the range is increased by a factor of 2–3 compared with the prototype device.

где

функция правдоподобия;
x_l, x_k - элементы вектора

(x₁ = x_n, x₂ = y_n, x₃ = V_x, x₃ = V_y - значения декартовых координат цели и скоростей их изменения в момент наблюдения t_n (4));
М{.} - знак статистического усреднения.The potential accuracy in FIG. 6 was determined by the Fisher information matrix [7, p. 332-334; 8, p.204-205]. For the target motion model ΔT = (n-1) T adopted on the measurement interval of the target motion parameters (5), and the accepted statistical characteristics of the measurement errors of the primary parameters - Doppler frequency and angular coordinate (9), the elements of the Fisher matrix:

Where

likelihood function;
x _l , x _k - vector elements

(x ₁ = x _n , x ₂ = y _n , x ₃ = V _x , x ₃ = V _y are the values of the Cartesian coordinates of the target and the rates of their change at the time of observation t _n (4));
M {.} Is the sign of statistical averaging.

ошибок определения параметров траектории находятся как диагональные элементы матрицы, обратной матрице Фишера с элементами (18).Dispersions

errors in determining the parameters of the trajectory are found as diagonal elements of the matrix, the inverse of the Fisher matrix with elements (18).

 Modeling showed that the proposed device allows you to determine the location of the target with accuracy close to potentially achievable throughout the entire trajectory of the target in the detection zone.

 The operability of the device is ensured by the use of well-known and new blocks in it, the implementation of which does not require additional inventive creativity.

Literature
1. Theoretical foundations of radar / Shirman Y.D., Golikov VN, Busygin I.N. and etc.; Ed. POISON. Shirman. - M .: Owls. Radio, 1970 .-- 560 p.

 2. Chernyak V.S., Zaslavsky L.P., Osipov L.V. Multiposition radar stations and systems // Foreign Radio Electronics. - 1987. - N 1. - S. 9-30.

 3. Blyakhman A.B., Samarin A.V. Radar method for determining the motion parameters of an object: Application for invention N 98101955/09 (002027) with a priority of 02.02.98. Patent N 2133480.

 4. Finkelstein M.I. Basics of radar. - M .: Owls. Radio, 1973.

 5. Blyakhman A. B., Ryndyk A. G., Kovalev F. N. Device for determining the motion parameters of an object: Application for invention N 97117868/09 (019049) with priority from 10.29.97. Patent N 2124220.

 6. Guide to radar: 4 t. / Ed. M. Skolnik; trans. from English under the general. ed. K.N. Trofimova. - M .: Owls. Radio, 1978.- T. 4.- 375 s.

 7. Chernyak V.S. Multiposition radar. - M .: Radio and communications, 1993 .-- 416 p.

 8. Sage E., Mels J. The theory of evaluation and its application in communication and management. - M .: Communication, 1976 .-- 496 p.

Claims (1)

 A device for determining the motion parameters of an object, containing a transmitting position and at a point remote from it, a receiving position consisting of an antenna connected to a receiving device, the output of which is connected to the inputs of the Doppler frequency measuring unit and the inputs of the measuring unit for the direction of arrival of the interference signal, extrapolation unit for the measured parameters , one input of which is connected to the output of the unit for measuring the Doppler frequency, the second input - with the output of the unit for measuring the direction of arrival of the interference signal ala, and the output is connected to the input of the unit for calculating the instant of time the target intersects the base line, the unit for determining the position surface connected by one input to the output of the unit for calculating the instant of the target's intersection with the base line, the second with the output of the extrapolation unit of the measured parameters, and the output with one the inputs of the block for calculating the trajectory parameters, the other input of which is connected to the output of the block for measuring the direction of arrival of the interference signal, characterized in that the statistics determination block is introduced into it the error characteristics of measuring the Doppler frequency and the direction of arrival of the interference signal and a block for the final calculation of the trajectory parameters, moreover, one input of the unit for determining the statistical characteristics of the errors of measuring the Doppler frequency and direction of arrival of the interference signal is connected to the output of the block for measuring the direction of arrival of the interference signal, the second input to the output measuring the Doppler frequency, and the output is connected to one of the four inputs of the block of the final calculation of the path parameters, the other three inputs of which are separately connected to the outputs of the unit for measuring the direction of arrival of the interference signal, the unit for measuring the Doppler frequency and the unit for calculating the path parameters, while the output of the entire device is the output of the block for the final calculation of the path parameters.

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