RU2567214C1 - Multi-frequency antenna array with digital signal processing for determining coordinates of radar target - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: multi-frequency antenna array, having a system for generating a coherent array of equidistant frequencies and N radiating elements, further includes: N analogue receivers, N analogue-to-digital converters, a measurement result storage device, an adder, N multipliers, a computing device, a measurement result display device and a control device.

EFFECT: high accuracy of determining coordinates of a target owing to multi-channel reception, digital combined posterior processing of signals with different frequencies and random distribution of signals with different frequencies on numbers of radiating elements while simultaneously increasing operating speed owing to single radiation and reception of signals with different frequencies and obtaining information on a radar environment in an operating area at the processing step and not through multiple probing of space in time.

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Description

The invention relates to antenna technology and can be used in radar stations designed to detect targets, determine the distance to the target and determine the coordinates of the target.

Multiband antennas are known [see "Foreign Radio Electronics" No. 3, 1978, pp. 38-62]. Two-frequency antenna arrays are a special case of such antennas [see L.I. Ponomarev, V.I. Stepanenko "Scanning multi-frequency antenna arrays" / Ed. L.I. Ponamareva. - M .: Radio engineering, 2009. - 328 p., Ill.]. There is a device using four types of waveguide emitters, designed to form from one aperture electrically controlled radiation in the range of 1-10 GHz [Boyns J.E., Provencher J.N., Experimental results of a multifrequency array antenna. - IEEETrans. AP, 1972, 20, no. 1, p. 107-106].

A disadvantage of the known devices is that in them the scanning of space is carried out due to the phase shift of the signal at each antenna element by means of phase shifters, while information about the radar situation in the working area is obtained due to multiple sounding of the space, which leads to significant time costs when scanning the entire working zones, as well as the fact that the echo signals obtained by sensing the space at different frequencies are processed independently, thereby not providing I target positioning accuracy in range due to coherent addition of signals of different frequencies.

The closest in technical essence to the device is a scanning antenna, the circuit of which is shown in figure 2 [Application No. 2153076, France, publication June 1, 1973], comprising: a system for forming a coherent grid of equidistantly upset frequencies (1) and N radiating elements (2), connected in parallel with this system, and the frequencies of the signals along the lattice elements from the 1st to the Nth are arranged in order of increasing or decreasing frequency, and the frequency diskette Δf between adjacent elements is a constant value.

. Причем частоты сигналов по элементам решетки от 1-го до N-ого располагаются последовательно в порядке возрастания частоты. Расчет проведен согласно выражению:The disadvantage of the closest technical solution is the impossibility of simultaneously determining the angular position of the target and its range, which is associated with the peculiarity of the formation of the maximum intensity of the total signal generated by the prototype (see Fig. 3), as well as the time interval required to review the entire working area from for the need for multiple sounding of space, due to the lack of the possibility of a posteriori signal processing. The peculiarity lies in the fact that the maximum intensity of the total signal when the frequencies are arranged along the elements of the lattice in ascending or descending order has a characteristic shape in the form of an arc of a circle. This form of maximum intensity allows you to determine the distance to the target, but does not allow you to determine the angular coordinates of the target with high accuracy. The authors calculated the maximum intensity of the total signal at a fixed moment of time as applied to isotropic radiating elements under the following initial conditions: the number of radiating elements N = 54, the distance between the elements d = 0.5 λ ₁ , λ ₁ = 0.09 m, λ _N = 0.03 m, $$\Delta \lambda =\frac{{\lambda }_{\mathrm{one}}-{\lambda }_N}{N}$$

. Moreover, the frequency of the signals along the elements of the lattice from the 1st to the Nth are arranged sequentially in order of increasing frequency. The calculation is carried out according to the expression:

- вектор координат точки расположения i-ого излучающего элемента, x и y - координаты точки наблюдения,

- волновое число,

- расстояние от точки наблюдения до i-ого излучающего элемента.Where

is the coordinate vector of the location point of the i-th radiating element, x and y are the coordinates of the observation point,

is the wave number

- the distance from the observation point to the i-th radiating element.

The technical result of the invention is to increase the accuracy of determining the coordinates of the target while improving performance.

The specified technical result is achieved in that the known device containing a system for forming a coherent grid of equidistant frequencies and N radiating elements connected in parallel with this system is characterized in that N analog receivers, N analog-to-digital converters (ADCs) are introduced into it, the device storing measurement results, a summing device, N multipliers, a computing device, a device for displaying measurement results and a control device, wherein N emitting elements parallel connected to N analog receivers that are parallel connected to the ADC, which are parallel connected to the storage device for the measurement results, N outputs of which are connected to the corresponding inputs of the multipliers, the outputs of which are connected to the N inputs of the summing device, the output of which is connected to the control device, the outputs of which are connected respectively, to a system for forming a coherent grid of equidistant upset frequencies, to a device for displaying measurement results, to a storage device p measurement results and a computing device, N outputs of which are connected in parallel to N multipliers, and the outputs of the coherent frequency grid forming system are connected to the inputs of the radiating elements, the distance between adjacent radiating elements is chosen equal to half the wavelength corresponding to the minimum frequency generated by the coherent grid forming system of equidistant upset frequencies, emitting elements are arranged so that signals with different frequencies are distributed according to the numbers of the radiation the constituent elements of the 1st to N-th randomly.

The proposed device design allows to increase the accuracy of determining the coordinates of the target due to multi-channel reception, digital joint a posteriori processing of multi-frequency signals and random distribution of signals with different frequencies according to the numbers of radiating elements (see Fig. 4), as well as to improve performance due to single radiation and multi-frequency reception signals and obtaining information about the radar situation in the working area at the processing stage, and not due to multiple sounding of space in belt.

. Причем частоты сигналов по элементам решетки от 1-го до N-ого располагаются в случайном порядке. Расчет проведен согласно выражению:The authors calculated the maximum intensity of the total signal generated at the stage of processing the echo signals, as applied to isotropic radiating elements under the following initial conditions: the number of radiating elements N = 54, the distance between the elements d = 0.5 λ ₁ , λ ₁ = 0.09 m, λ _N = 0.03 m $$\Delta \lambda =\frac{{\lambda }_{\mathrm{one}}-{\lambda }_N}{N}$$

. Moreover, the frequency of the signals along the elements of the lattice from the 1st to the Nth are arranged in a random order. The calculation is carried out according to the expression:

- вектор координат точки расположения i -ого излучающего элемента, x и y - координаты точки наблюдения, $$k_i=\frac{2\pi }{\lambda i}$$

- волновое число, $$L\left({\overrightarrow{r}}_i,x,y\right)$$

- расстояние от точки наблюдения до i-ого излучающего элемента. Из сравнения результатов расчета, представленных на фиг. 3 и фиг. 4, видно, что максимум интенсивности суммарного сигнала, формируемого заявляемым устройством, позволяет точнее определить координаты радиолокационной цели.Where $${\overrightarrow{r}}_i$$

is the coordinate vector of the location point of the i-th radiating element, x and y are the coordinates of the observation point, $$k_i=\frac{2\pi }{\lambda i}$$

is the wave number $$L\left({\overrightarrow{r}}_i,x,y\right)$$

- the distance from the observation point to the i-th radiating element. From a comparison of the calculation results shown in FIG. 3 and FIG. 4, it is seen that the maximum intensity of the total signal generated by the claimed device, allows you to more accurately determine the coordinates of the radar target.

The analysis of the prior art allows us to establish that analogues that characterize a set of features that are identical to all the features of the claimed technical solution contained in the claims proposed by the applicant are absent, which indicates compliance of the claimed invention with the “novelty” protection condition.

Search results for known solutions in this and related fields of technology in order to identify features that match the distinctive features of the claimed device showed that no solutions having features matching its distinctive features were found in publicly available information sources. The prior art also does not confirm the popularity of the influence of the distinctive features of the claimed invention on the specified claimed technical result, therefore, the claimed invention meets the condition of patentability "inventive step".

The claimed technical solution "Multi-frequency antenna array with digital signal processing for determining the coordinates of a radar target" is industrially applicable, since the combination of characteristics characterizing it provides the possibility of its implementation, operability and reproducibility, and standard materials and equipment can be used for its implementation.

In FIG. 1 presents a structural diagram of the inventive device. In FIG. 2 presents a structural diagram of a prototype. In FIG. 3 shows the spatial distribution of the intensity of the signal generated by the prototype. In FIG. 4 shows the spatial distribution of the intensity of the signal generated by the claimed device. In FIG. 5 presents a diagram of the algorithm of the claimed device. In FIG. 6 is a schematic representation of the partition of the work area into M resolution elements.

A multi-frequency antenna array with digital signal processing for determining the coordinates of a radar target contains: a system for the formation of a coherent grid of equidistant frequencies (1) and N radiating elements (2.1-2.N) parallel to this system, N analog receivers (3.1-3. N), N analog-to-digital converters (ADCs) (4.1-4.N), a device for storing measurement results (5), N multipliers (61-6.N), a computing device (7), a summing device (8), a device display of measurement results (9) and control unit (10), and N radiating elements are connected in parallel with N analog receivers, which are connected in parallel with ADCs, which are connected in parallel to a storage device for measurement results, N outputs of which are connected to the corresponding inputs of multipliers, the outputs of which are connected to N inputs of the summing device, the output which is connected to a control device, the other outputs of which are connected respectively to a system for forming a coherent grid of equidistant upset frequencies, to a display device measurement ultrasounds, to the storage device for the measurement results and the computing device, N outputs of which are connected in parallel to N multipliers, the outputs of the coherent frequency grid system being connected to the inputs of the radiating elements, the distance between adjacent radiating elements is chosen equal to half the wavelength corresponding to the minimum frequency generated a system for the formation of a coherent grid of equidistant upset frequencies, the radiating elements are arranged so that signals with different pilots at were distributed by number of radiating elements of the 1st to N-th randomly.

As radiating elements (2.1-2.N), slotted, microstrip or vibrator radiators, open ends of waveguides of various types and sizes, as well as a combination of these or other types of radiators can be used. The radiating elements (2.1-2.N) are fixed on the basis of a composite material.

Signals with different frequencies along the radiating elements (2.1-2.N) from the 1st to the Nth are distributed randomly.

A storage device for measurement results (5), multipliers (6.1-6.N), a computing device (7), a summing device (8) can be implemented using programmable logic integrated circuits (FPGAs). The control device (10) can also be implemented using FPGAs or implemented on computers such as IBM.

The remaining blocks and devices that are part of the device are performed according to the typical requirements for these devices.

, The operation algorithm of the multi-frequency antenna array with digital signal processing to determine the coordinates of the radar target (Fig. 4) is as follows. From the control device (10), control signals are sent to the system for generating a coherent grid of equidistant frequencies (1), to the storage device for the measurement results (5) and to the computing device (7). When a control signal arrives at the device for storing measurement results (5), it switches to recording mode. Upon receipt of a control signal by the system for forming a coherent frequency network (1), signals are transmitted to the radiating elements (2.1-2.N). At the same time, a probing signal of the form $${\displaystyle \sum _{i=\mathrm{one}}^N\dot{E}\left({\overrightarrow{r}}_i,f_i\right)}$$

,

- вектор координат i-ого излучающего элемента, f_i - рабочая частота i-ого излучающего элемента. Эхосигналы $$\dot{S}\left({\overrightarrow{r}}_i,f_i\right)$$

, i=1, …, N, поступают на N излучающих элементов (2.1-2.N), принимаются аналоговыми приемниками (3.1-3.N), преобразуются аналогово-цифровыми преобразователями (4.1-4.N) в цифровую форму и записываются в устройство хранения результатов измерений. Where $${\overrightarrow{r}}_i$$

is the coordinate vector of the i-th radiating element, f _i is the operating frequency of the i-th radiating element. Echoes $$\dot{S}\left({\overrightarrow{r}}_i,f_i\right)$$

, i = 1, ..., N, are received by N radiating elements (2.1-2.N), received by analog receivers (3.1-3.N), converted by analog-to-digital converters (4.1-4.N) into digital form and written to the storage device of the measurement results.

, i=1 …, N, где $$k_i=\frac{2\pi f_i}{c}$$

- волновое число, с - скорость света. После поступления сигналов устройство хранения результатов измерений (5) переходит в режим хранения и передачи сигналов на умножители (6.1-6.N). Полученные сигналы поступают на соответствующие умножители (6.1-6.N). При поступлении управляющего сигнала на вычислительное устройство (7) в нем происходит вычисление N комплексных весовых коэффициентов $$\dot{\Omega }\left({\overrightarrow{R}}_j,{\overrightarrow{r}}_i,k_i\right)$$

для j=1 по формуле:As a result, a set of values of amplitudes and phases of echo signals is stored in the device for storing measurement results (5) $${\dot{S}}_i=S_i{e}^{i{k}_i{\varphi }_i}$$

, i = 1 ..., N, where $$k_i=\frac{2\pi f_i}{c}$$

- wave number, s - speed of light. After the signals are received, the device for storing the measurement results (5) switches to the mode of storage and transmission of signals to the multipliers (6.1-6.N). The received signals are sent to the corresponding multipliers (6.1-6.N). When the control signal arrives at the computing device (7), it calculates N complex weighting coefficients $$\dot{\Omega }\left({\overrightarrow{R}}_j,{\overrightarrow{r}}_i,k_i\right)$$

for j = 1 by the formula:

- вектор, определяющей положение центра j -го элемента разрешения (см. фиг 6), j=1…М, γ_oi - начальная фаза излучаемого сигнала на частоте f_i.Where $${\overrightarrow{R}}_j$$

is the vector that determines the position of the center of the jth resolution element (see Fig. 6), j = 1 ... M, γ _oi is the initial phase of the emitted signal at a frequency f _i .

и комплексных амплитуд $${\dot{S}}_i=S_i{e}^{i{k}_i{\varphi }_i}$$

, поступают на суммирующее устройство (8), где они суммируются, а с его выхода поступают на управляющее устройство (10), где сохраняется модуль полученного комплексного значения $$Z\left({\overrightarrow{R}}_1\right)$$

.The calculated complex weights go to the corresponding multipliers (6.1-6.N). Values obtained by multiplying the corresponding complex weights $$\dot{\Omega }\left({\overrightarrow{R}}_j,{\overrightarrow{r}}_i,k_i\right)$$

and complex amplitudes $${\dot{S}}_i=S_i{e}^{i{k}_i{\varphi }_i}$$

, go to the summing device (8), where they are summed, and from its output go to the control device (10), where the module of the obtained complex value is stored $$Z\left({\overrightarrow{R}}_{\mathrm{one}}\right)$$

.

. Таким образом вычисляют сигнальную функцию (апостериорное когерентное сложение эхосигналов, полученных при зондировании пространства):After saving, the control signal is supplied to the computing device (7) and the complex weight coefficients are calculated for j = 2. The calculated complex weights go to the corresponding multipliers (6.1-6.N). The values from the outputs of the multipliers are sent to the summing device (8), and from its output to the control device (10), where the module of the obtained complex value is stored $$Z\left({\overrightarrow{R}}_2\right)$$

. In this way, the signal function (a posteriori coherent addition of echo signals obtained by sensing space) is calculated:

, j=1…M.When j = M + 1, the control device (10) sends a signal to the display device of the measurement results (9) and the calculated values are displayed on it $$Z\left(\overrightarrow{R}j\right)$$

, j = 1 ... M.

Claims (1)

A multi-frequency antenna array with digital signal processing for determining the coordinates of a radar target, containing a system for generating a coherent grid of equidistant frequencies and N radiating elements connected in parallel with this system, characterized in that N analog receivers and N analog-to-digital converters (ADCs) are introduced into it ), a device for storing measurement results, an adder, N multipliers, a computing device, a device for displaying measurement results, and a device for control, and N radiating elements are connected in parallel with N analog receivers, which are connected in parallel with ADCs, which are parallel connected to the storage device of the measurement results, N outputs of which are connected to the corresponding inputs of the multipliers, the outputs of which are connected to the N inputs of the summing device, the output of which is connected to control, the outputs of which are connected respectively to the system for forming a coherent grid of equidistant upset frequencies, to the display device of measurements, to a storage device for the measurement results and a computing device, N outputs of which are connected in parallel to N multipliers, the outputs of the coherent grid formation system of equidistant detuned frequencies being connected to the inputs of the radiating elements, the distance between adjacent radiating elements is chosen equal to half the wavelength corresponding to the minimum frequency formed by the system of forming a coherent grid of equidistant upset frequencies, the radiating elements are positioned so that Signals with different frequencies were distributed according to the numbers of radiating elements from the 1st to the Nth according to a random law.

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