RU2713159C1 - Method of forming circular area of electronic scanning of cylindrical phased antenna array with increased rate of view - Google Patents

Abstract

FIELD: radar ranging.

SUBSTANCE: invention relates to radar ranging and can be used in radar stations with cylindrical (circular) phased antenna array. In a radar station with a cylindrical phased antenna array with radiators arranged equidistantly on its surface, which are combined into several sectors, wherein adjacent sectors operate at different frequencies, which form a common multilobe pattern, consisting of sector diagrams of directivity, number of which is equal to the number of sectors, scanning in cylindrical phased antenna array is carried out by simultaneous coordinated movement of all sector radiation patterns, wherein inside each angular sector there are radiators (emitter rows) passive for this sector, which are active for neighboring sectors, and inside the neighboring sectors there are radiators (emitter rows) which are active for this sector, which are passive for neighboring sectors.

EFFECT: technical result consists in reducing width of main lobes of sector diagrams without reducing the speed of scanning space, without complicating FAA and while maintaining its size.

1 cl, 3 dwg

Description

The invention relates to radar and can be used in radar stations.

Currently, radar with a phased antenna array (PAR) is widely used, which allows a quick overview of the space (small time spent on the detection, capture and tracking of targets), adaptation to a specific radio environment, ensuring electromagnetic compatibility, etc. Of the radar with a phased antenna array, of particular interest are the cylindrical and annular (annular - a special case of cylindrical arrays) phased antenna array. A cylindrical phased antenna array provides the possibility of wide-angle (up to 360 °) scanning with a beam of constant width and shape in the azimuthal plane (Antennas and microwave devices. Designing phased antenna arrays: Textbook for universities, BC Filippov, LI Ponomarev, A.Yu. Grinev et al., Edited by D.I. Voskresensky, 2nd ed. M. Radio and Communications, 1994, p. 126), in contrast to planar ones, in which the limiting values of the scanning angle are of the order of 60-70 ° (Reference on radiolocation, editor M. Skolnik lane with English, ed . "Soviet Radio" ML 977 vol. 2, p. 135.). In addition, a flat phased antenna array has a dependence of the azimuthal angular coordinate measurement characteristics on the frequency and on the position of the beam in space (Antennas with electric scanning, O.G. Vendik, M.D. Parnes, edited by L.D. Bahrakh. - Moscow : Science Press, 2002, c 154-155). The measurement characteristics of azimuthal angular coordinates in a cylindrical phased antenna array depend little on frequency and on the position of the beam in space. This is also due to the fact that in a cylindrical phased antenna array there is weak interconnection between emitters compared to flat ones (Antennas and microwave devices. Designing phased antenna arrays: Textbook for universities, BC Filippov, LI Ponomarev, A . Yu. Grinev et al., Edited by D.I. Voskresensky, 2nd ed. M. Radio and Communications, 1994, p. 126).

A cylindrical phased antenna array is a system of emitters arranged around a circle. The spatial orientation of the emitters is such that the direction of the maximum radiation pattern of each of them coincides with the direction of the radius of the corresponding antenna array at the location of the emitter. Under the emitter should be understood as a single emitter, and a system of several emitters (Antennas and microwave devices. Designing phased antenna arrays: Textbook for universities, BC Filippov, L.I. Ponomarev, A.Yu. Grinev, etc. under Edited by D.I. Voskresensky 2nd ed. M. Radio and Communications, 1994, p. 126).

A known method of forming a circular zone of electronic scanning of a cylindrical phased antenna array (US Pat. No. 2619445, IPC H01Q 21 / 00_, published 05/15/2017), taken as a distant analogue of the claimed invention, based on the placement on its surface of emitters, united along the generatrix of the cylinder in equidistant located lines of emitters forming the same radiation patterns, determining the dimensions of the angular sector of the location of the emitter lines, radiation of a flat field by electronic phase control by shifting the signals passing through the emitters, and for any direction of the beam, active lines of emitters are separated inside the angular sector by bringing the signal to them by electronic switching, and for the in-phase addition of the emitted fields in the direction of the antenna beam, the phases of the signals supplied to the active lines of emitters are changed to values

Where:

i - numbers of active lines of emitters (i> 0);

λ is the wavelength in the propagation medium of the radiated field;

R is the radius of the cylinder;

φ ₀ - the direction of the antenna beam in the azimuthal plane;

φ _i - the angular position of the i-th active line of emitters in the azimuthal plane;

ψ _i - the initial phase of the signal supplied to the i-th active line of emitters

This method of forming a circular zone of electronic scanning of a cylindrical phased antenna array allows you to control in the azimuthal plane of the cylindrical headlamp relative (to the maximum of the LH) level of maximum side lobes.

However, this method has a low rate of view (a lot of time spent on the detection, capture and tracking of targets). The low rate of view is caused by the fact that this cylindrical phased antenna array has only one beam formed by emitters located in a limited sector;

Another way of forming a circular zone of electronic scanning of a cylindrical phased antenna array, selected as a prototype in connection with the similarity of the technical task being performed, is a method of forming a circular zone of electronic scanning of a cylindrical phased antenna array based on the placement of emitters united along the cylinder generatrix in an equidistant manner on its surface located lines of emitters forming the same radiation patterns combined in (divided na) several sectors, forming a common multi-petal radiation pattern, consisting of the same sector radiation patterns, the number of which is equal to the number of sectors. Scanning is carried out by the simultaneous coordinated movement of all sector radiation patterns. (A radar station with a digital axisymmetric active antenna array as a promising direction for the development of all-round radar stations, M.V. Indenbom, R.P. Makhlin, Bulletin of the Concern East Kazakhstan Almaz-Antey No. 3, 2017).

This method has a high speed view of the space.

However, this method has the following disadvantages:

- the use of this method leads to a high level of side lobes in the azimuthal plane of the cylindrical PAR (relative to the maximum of the beam).

- the need for a small width of the main lobe at a high speed of viewing the space leads to an increase in size and complication of the PAR. The width of the main lobe is determined by the size of the sector, i.e. the number of sectors, since the number of main lobes is equal to the number of sectors. Reducing the width of the main lobe leads to an increase in the size of the sector, and as a result to a decrease in the number of sectors. A decrease in the number of sectors, respectively, leads to a decrease in the speed of viewing the space. Reducing the width of the main lobes of sector directional patterns without decreasing the speed of the space survey can be obtained by increasing the total number of emitters of the cylindrical headlamp, which inevitably leads to an increase in size and complication of the headlamp.

The technical result of the invention is to reduce the width of the main lobes of the sector radiation patterns without reducing the speed of the space survey, without complicating the HEADLIGHT and while maintaining its size.

The indicated technical result is achieved in that in a radar station with a cylindrical phased antenna array with emitters placed equidistant on its surface, combined into (divided into) several sectors, and adjacent sectors operating at different frequencies, forming a common multi-lobe radiation pattern, consisting of the same sector radiation patterns, the number of which is equal to the number of sectors, scanning in a cylindrical phased antenna array is carried out simultaneously coordinated movement of all sector patterns, moreover, inside each angular sector there are passive emitters for this sector (emitter lines) that are active for neighboring sectors, and inside neighboring sectors there are emitters active for this sector (emitter lines) that are passive for neighboring sectors

In the proposed method, there are significant differences from the above methods.

In the method taken as an analogue of the claimed invention (Pat. No. 2619445, IPC H01Q 21 / 00_, published 05/15/2017) a circular zone is formed by electronic scanning with a single beam, the size of the selected sector (the number of lines of emitters) is not a fixed value and can vary, a significant part of the emitters of the phased array, including those entering the selected sector, are passive, that is, a signal is not supplied to them.

In the proposed method, a cylindrical phased antenna array with emitters placed equidistantly on its surface, united along the generatrix of the cylinder into an equidistant array of emitters, is divided into several sectors, each operating at its own frequency, forming a common multi-lobe radiation pattern consisting of identical sector directivity patterns, number which is equal to the number of sectors, scanning in a cylindrical phased antenna array is carried out simultaneously with concerted movement of pie charts directivity, hence the circular zone is formed by electronic scanning of multiple (rather than single) directivity pie charts, the size of each sector is fixed. During operation of the antenna array (Pat. No. 2619445, IPC H01Q 21 / 00_, published May 15, 2017), part of the emitters of the phased antenna array, including those entering the selected sector, are passive, and no signal is supplied to them. In the proposed method, a signal is supplied to all emitters of a phased array, all emitters of a phased array are active.

In the method chosen as a prototype (Radar station with a digital axisymmetric active antenna array as a promising direction for the development of radar stations of circular visibility, M.V. Indenbom, R.P. Makhlin, Bulletin of the Concern East Kazakhstan Almaz-Antey No. 3, 2017 .) a cylindrical phased antenna array is divided into several sectors, forming a common multi-petal radiation pattern, consisting of the same sector radiation patterns, the number of which is equal to the number of sectors, scanning in a cylindrical phased antenna array is carried out by the simultaneous coordinated movement of all sector radiation patterns, which ensures a high viewing rate, while the level of the side lobes of the radiation pattern and the width of the main lobe of the radiation pattern are determined by the number of emitters (aperture size) and the amplitude distribution in the sector of the antenna array with a fixed number emitters. Direct application of the method for reducing the level of side lobes proposed in the invention (US Pat. No. 2619445, IPC H01Q 21 / 00_, published 05/15/2017), leads to a decrease in the level of side lobes. However, this happens:

- expansion of the main lobe of the sector radiation pattern;

- a decrease in the potential of the antenna array (due to the appearance of passive emitters and, therefore, due to a decrease in the radiated power) and, accordingly, either a decrease in the target detection range or an increase in the viewing time.

To reduce the width of the main lobe of the sector directional pattern, it is necessary to increase the aperture (increase in the number of emitters) and, accordingly, which inevitably causes an increase in the size of the entire cylindrical phased antenna array, to increase the number of equipment (transceiver modules), etc.

In the proposed method, the size of the aperture of each sector is larger than the size of each sector in the antenna array selected for the prototype through the use of part of the aperture of neighboring sectors. This allows you to reduce the level of the side lobes (including in comparison with the method of reducing the level of side lobes proposed in the invention (US Pat. No. 2619445, IPC H01Q 21/00., Published 05/15/2017), reduce the width of the main lobe of the radiation pattern, when maintaining the dimensions of the entire cylindrical phased antenna array and without increasing the equipment.

Thus, in the considered methods of forming a circular electronic scanning zone of a cylindrical phased antenna array, either a low viewing rate is obtained with a low level of side lobes and a narrow main lobe of the radiation pattern (US Pat. No. 2619445, IPC H01Q 21/00., Published 05/15/2017), or a high viewing rate with a high level of side lobes and a wide main lobe of the radiation pattern at a fixed size of the antenna array, that is, they cannot provide a high viewing rate with a low level of side ECTS and a narrow main lobe of the radiation pattern for fixed size array,

This allows us to conclude that the claimed invention meets the patentability criterion of "inventive step".

The invention will be more clear from the above description and the accompanying graphic materials.

In FIG. 1 shows an example of a cylindrical HEADLIGHT realizing the proposed method.

In the drawing and in the text, the following notation:

1 - active emitters located inside the angular sector 1;

2 - emitters located inside the angular sector 1, which are passive for sector 1, and are active for sector 4;

3 - emitters located inside the angular sector 1, which are passive for sector 1, and are active for sector 2;

4 - emitters geometrically located in sector 4, which are active for sector 1, and are passive for sector 4;

5 - emitters geometrically located in sector 2, which are active for sector 1, and are passive for sector 2.

In FIG. 2 are shown:

6 is a radiation pattern of a cylindrical phased antenna array that implements the method selected as a prototype;

7 is a radiation pattern of a cylindrical phased antenna array that implements the claimed method;

8 is a radiation pattern of a cylindrical phased antenna array that implements the method selected as a prototype using the method of reducing the level of side lobes proposed in the invention (US Pat. No. 2619445, IPC H01Q 21/00., Published 05/15/2017).

In FIG. 3 are shown:

9 is a fragment of the radiation pattern of a cylindrical phased antenna array that implements the claimed method;

10 is a fragment of the radiation pattern of a cylindrical phased antenna array that implements the method selected as a prototype;

11 is a fragment of the radiation pattern that implements the method selected as a prototype using the method of reducing the level of side lobes proposed in the invention (US Pat. No. 2619445, IPC H01Q 21/00., Published 05/15/2017).

Let us explain the principle of operation of the claimed cylindrical phased antenna array.

The formation of a circular zone of electronic scanning of a cylindrical headlamp, in which all lines of emitters on a cylindrical surface are equidistant, by the proposed method is as follows:

To form a common multi-petal radiation pattern consisting of the same sectorial radiation patterns, the entire headlamp is divided into sectors (sectors 1, 2, 3, 4). Sectors are bounded by solid lines (see Fig. 1).

As an example, consider sector 1.

A decrease in the level of the side lobes and a decrease in the width of the main lobe of the sector beam pattern of sector 1 is made by eliminating from the composition of the active emitters of the antenna array sector 1 (see Fig. 1) part of the "edge" emitters geometrically located inside this sector (see Fig. 1 ), emitters 2 adjacent to sector 4 are passive for sector 1 (active for sector 4), emitters 3 adjacent to sector 2 are passive for sector 1 (active for sector 2).

Reducing the width of the main lobe of the sector beam pattern occurs due to the expansion of the aperture of the antenna array of sector 1. The expansion of the aperture of the antenna array of sector 1 is achieved by using a portion of emitters geometrically located (incoming) in neighboring sectors (see Fig. 1, emitters 4 geometrically located (incoming) in sector 4, emitters 5 geometrically located (incoming) in sector 2). In this case, emitters 4, 5, geometrically extending beyond sector 1 (geometrically located in sectors 4, 5) are active emitters of sector 1.

The resulting sector aperture is indicated by a dashed line. The size of the sector aperture is greater than 360 / K, where K is the number of sectors.

In addition, through the use of emitters 4, 5 there is an additional decrease in the level of the side lobes of the sector radiation pattern.

Phase shifts for all sector emitters are determined based on the phase front necessary to construct a given directional pattern of the sector (s).

A decrease in the level of the side lobes and a decrease in the width of the main lobe of the sector radiation pattern occurs in all sectors of the cylindrical phased antenna array.

Adjacent sectors operate at different frequencies, either with a small number of sectors or using a wide range of frequencies, each of the sectors operates at its own frequency.

As can be seen from the given sector patterns, the level of the side lobes decreased by 4.8 dB (from 10.6 dB to 15.4 dB) (see Fig. 2 radiation patterns 6, 7). The application of the method for reducing the level of side lobes proposed in the invention (US Pat. No. 2619445, IPC H01Q 21 / 00_, published May 15, 2017) leads to a decrease in the level of side lobes by 3.9 dB (from 10.6 dB to 14.5 dB ) (see. Fig. 2 radiation patterns 8, 6).

The width of the main lobe of the radiation pattern of the inventive antenna array at the level of 3 dB is 3.6 degrees. (see Fig. 3 radiation pattern 9). The width of the main lobe of the antenna array of the prototype is 4.0 degrees. (see Fig. 3 radiation pattern 10), the width of the main lobe of the radiation pattern of the antenna array of the prototype using the method of reducing the level of side lobes proposed in the invention (US Pat. No. 2619445, IPC H01Q 21/00., published 05/15/2017) is 4 , 4 deg) (see. Fig. 3 radiation pattern 11),

The magnitude of the decrease in the level of the side lobes and the decrease in the width of the main lobe of the radiation pattern depends on the number of emitters in the sector, i.e. on the number of sectors and on the size of the entire cylindrical phased antenna array.

The number of sectors of “edge” emitters excluded from the composition of the antenna array of a sector located inside a given sector is usually equal to the number of emitters geometrically located (incoming) in neighboring sectors. This allows you to create the same radiation patterns having a reduced level of side lobes and a small width of the main lobes of the sector radiation patterns for all sectors of the declared cylindrical phased antenna array.

The use of an active phased antenna array (AFAR) allows the easiest way to ensure a high rate of view of space through the use of a multi-lobe radiation pattern. In addition, when using an active phased antenna array (AFAR), the maximum effective surface of a multi-beam headlamp is obtained (Radar station with a digital axisymmetric active antenna array as a promising direction for the development of all-round radar stations, M.V. Indenbom, R.P. Makhlin, Bulletin of the Concern East Kazakhstan Almaz-Antey No. 3, 2017).

Using this invention, it is possible to create a radar with a cylindrical phased antenna array having a low level of side lobes, a small width of the main lobes of the sector radiation patterns without reducing the speed of the space survey, without complicating the PAR and maintaining its size.

Claims (1)

The method of forming a circular electronic scanning zone of a cylindrical phased antenna array with an increased viewing rate of a radar station with a cylindrical phased antenna array, with emitters placed equidistantly on its surface, combined in several sectors, forming a common multi-lobe radiation pattern consisting of sector radiation patterns, the number of which is equal to number of sectors, scanning in a cylindrical phased array is carried out simultaneously by coordinated movement of all sector radiation patterns, characterized in that within each angular sector there are emitters passive for a given sector (emitter lines) that are active for neighboring sectors, and within adjacent sectors there are emitters active (active emitters for this sector) (emitter lines) for neighboring sectors.

Images