A method for implementing a phase-frequency scanning single-pulse antenna sublobe stealth beam

Abstract

The application relates to a method for realizing a sidelobe-cancelling beam of a phase-frequency scanning monopulse antenna, and belongs to the technical field of antennas. By virtue of the technical advantages of an active phase-frequency scanning antenna system, a sidelobe-cancelling beam is realized by giving a set of specific amplitude-phase weighting and optimizing combination of an antenna beam, the influence of a space interference signal on the performance of a radar is reduced, the actual measurement effect reaches the expected target, and the method can be used as a reference for realizing a sidelobe-cancelling beam.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology and relates to a method for realizing sidelobe shadowing beam in a phase-frequency swept monopulse antenna. It is mainly applied to phase-frequency swept monopulse antenna systems that require suppression of sidelobe interference signals, and can also be applied to other antenna systems that require anti-interference of sidelobes. Background Technology

[0002] A phase-frequency scanned antenna system is a two-dimensional electrically controlled scanning antenna. It typically employs a phased-controlled electronic scanning system in the azimuth plane and a traveling-wave array frequency scanning system in the elevation plane. Compared to a two-dimensional phase-scanned antenna system, the phase-frequency scanned antenna system offers the advantage of achieving two-dimensional electronic scanning functionality with minimal cost increase. Its disadvantage is a narrower electronic scanning range. When distributed active transceiver components are used for azimuth phased scanning, the phase-frequency scanned antenna system is called an active phase-frequency scanned antenna system. Each radiating element in the azimuth plane of the antenna array is connected to an active transceiver channel, enabling the simultaneous formation of single or multiple beams during reception. The beam pointing can be controlled to achieve flexible scanning over large angles. It features high system frequency response sensitivity, low RF loss, and fast system response speed. Due to its economic practicality, the phase-frequency scanned antenna system is still widely used as an antenna system for artillery emplacement reconnaissance and fire correction radar.

[0003] Monopulse technology refers to the technique of simultaneously realizing sum and difference beams within a single pulse. In radar angle measurement, monopulse sum and difference beams offer higher accuracy than other methods and are currently the preferred approach. The azimuth reception of an active phase-scanned antenna system employs DBF digital beamforming. Low-sidelobe sum and difference beams can be easily achieved through different weighted amplitude and phase. The elevation plane uses a traveling-wave frequency-scanned array. The most feasible method to achieve sum and difference beams is to split the frequency-scanned array in half and feed in simultaneous and out-of-phase monopulse beams to realize the frequency-scanned sum and difference beams.

[0004] When radar tracks and detects targets, the signals reflected back from reflectors other than the target in the surrounding space are all interference signals. The interference signals entering from the antenna sidelobes are the most significant component. To reduce interference from the sidelobes, antennas are generally required to have low sidelobes. Antenna design complexity increases exponentially with lower sidelobes, but this also increases the main lobe width, reducing the radar's angle-measuring splitting power. Sidelobe concealment is a relatively low-cost and effective technique for dealing with sidelobe interference without affecting the radar antenna's main beam detection performance. Summary of the Invention

[0005] Technical problems to be solved

[0006] To avoid the shortcomings of existing technologies, this invention provides a method for implementing sidelobe shadowing beams in a phase-frequency swept monopulse antenna. This method, without changing or adding hardware, only requires a set of feed amplitude and phase weightings to enable the antenna system to form a specific beam. Then, different beams are optimized and combined to achieve sidelobe shadowing. This testing approach for sidelobe shadowing beams can be widely promoted and applied in engineering practice.

[0007] Technical solution

[0008] A method for implementing a sidelobe shadowing beam of a phase-frequency swept monopulse antenna is characterized by: obtaining three beams by weighting different window functions, then vector synthesizing the first and second beams to obtain a fourth beam, and finally scalar superposition of the fourth and third beams to obtain the shadowing beam of the antenna system.

[0009] A further technical solution of the present invention: The first beam is an antenna beam synthesized from the amplitude and phase results of the Woodward synthesis method, which uses a weighted window function to design the beamwidth according to the 90° requirement for each element in the azimuth plane of the antenna system.

[0010] A further technical solution of the present invention: The second beam is an antenna beam synthesized by amplitude and phase weighting values ​​of two elements on the elevation plane of the antenna system with an amplitude difference of 6dB and phase reversal.

[0011] A further technical solution of the present invention: The third beam is an antenna beam synthesized by amplitude and phase weighting values ​​of equal amplitude and opposite phase between the upper and lower elements on the elevation plane of the antenna system.

[0012] A computer system is characterized by comprising: one or more processors, and a computer-readable storage medium for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the method described above.

[0013] A computer-readable storage medium is characterized by storing computer-executable instructions, which, when executed, are used to implement the above-described method.

[0014] Beneficial effects

[0015] This invention provides a method for implementing sidelobe concealment beamforming using a phase-frequency swept monopulse antenna. Utilizing the advantages of active phase-frequency swept antenna systems, and through an optimized combination of a specific set of amplitude and phase weights and the antenna beam, it achieves beam concealment of interference signals in the sidelobe region, reducing the impact of spatial interference signals on radar performance. The measured results meet the expected objectives and can be used as a reference for implementing sidelobe concealment beamforming. The beneficial effects are as follows:

[0016] 1. Based on the characteristics of active phase-frequency swept monopulse antenna systems, without increasing hardware costs, it is only necessary to change the beamforming window function and obtain the sidelobe-masked beam by performing mathematical operations on the beam. The implementation method is simple and flexible.

[0017] 2. By analyzing the sidelobe region and the main tangent, different beams are used to achieve precise concealment, ensuring that the beam amplitude of the area to be concealed by the main antenna is below the concealment beam, resulting in a good concealment effect and improving the radar's anti-jamming capability. Attached Figure Description

[0018] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0019] Figure 1 This is a block diagram illustrating the principle of the present invention.

[0020] Figure 2 This diagram illustrates the main beam receiving pattern of the phase-frequency swept antenna system according to an embodiment of the present invention.

[0021] Figure 3 This represents the azimuth-weighted Woodward window function direction pattern according to an embodiment of the present invention.

[0022] Figure 4 This indicates a pitch plane weighted amplitude difference of 6dB and a phase inversion window function radiation pattern in this embodiment of the invention.

[0023] Figure 5 express Figure 3 and Figure 4 Beam vector synthesis pattern;

[0024] Figure 6 This illustrates the shadow beam pattern of the phase-frequency swept antenna system according to an embodiment of the present invention.

[0025] Figure 7 This represents the difference between the radar beam and the stealth beam in the embodiment of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0027] The technical solution to the problem solved by this invention is as follows: For an active phase-scanning monopulse antenna system, active DBF digital beamforming technology is used in the azimuth plane to achieve receiving beamforming, and a two-element phase-comparison frequency-scanning monopulse technology with a segmented frequency-scanning structure is used in the elevation plane to achieve a two-dimensional monopulse beam. The implementation of the antenna system's stealth beam includes the following three beams: The first beam is the antenna beam synthesized from the amplitude and phase results of the Woodward synthesis method, which uses a weighted window function designed with a beamwidth of 90° for each element in the azimuth plane of the antenna system; the second beam is the antenna beam synthesized from the upper and lower elements in the elevation plane of the antenna system using amplitude and phase weighting values ​​with a 6dB phase difference and out-of-phase phase; the third beam is the antenna beam synthesized from the upper and lower elements in the elevation plane of the antenna system using amplitude and phase weighting values ​​with equal amplitude and out-of-phase phase. The method for implementing the antenna system's stealth beam is to first vector synthesize the first and second beams into a fourth beam, and then scalarly superimpose it with the third beam to form the final beam.

[0028] The first beam in this invention achieves a wide beamwidth of 90° in the azimuth plane, corresponding to ±45° of the azimuth plane phased scanning. In order to achieve full coverage within the entire phased scanning range of the azimuth plane, it is ensured that the sidelobe region of the phased scanning beam is under this wide beam during the scanning process.

[0029] The second beam in this invention achieves a zero-depth elevation difference beam in the elevation plane. In order to achieve the beam shadowing function of the sidelobe region on the azimuth plane main tangent plane, it is necessary to ensure that the beam amplitude of the main antenna on the azimuth plane main tangent plane is below this beam.

[0030] The fourth beam in this invention is formed by vector superposition of the first and second beams, which can achieve good concealment of the antenna main beam in areas other than the main tangent plane of the elevation plane.

[0031] The third beam in this invention is the directional difference beam of the antenna on the main tangent plane of the elevation plane. In order to achieve the function of beam shadowing of the sidelobe region on the main tangent plane of the elevation plane, it is necessary to ensure that the beam amplitude of the main antenna on the main tangent plane of the elevation plane is below this beam.

[0032] The stealth beam in this invention is achieved by superimposing the scalars of the third and fourth beams. This achieves the simultaneous increase of the amplitude of the main tangent plane of the stealth beam's elevation plane while having minimal impact on other beam directions, thus ensuring the stealth effect on the sidelobe region of the antenna's main beam throughout the entire airspace.

[0033] Figure 1 The schematic diagram of the present invention shows that three beams are first obtained by weighting different window functions, then the first beam and the second beam are vector synthesized to obtain a fourth beam, and finally the fourth beam and the third beam are scalar superimposed to obtain the antenna system's stealth beam.

[0034] like Figure 2 The diagram shown is a three-dimensional radiation pattern of the radar beam reception of the phase-frequency swept antenna system according to an embodiment of the present invention. The antenna system radiates a cone-shaped low-sidelobe beam. The active phase sweep in the azimuth plane points at 0°, and the frequency sweep in the elevation plane points at 10°. The sidelobes are extremely low in the region outside the main tangent plane.

[0035] like Figure 3 The diagram shown is an azimuth-weighted Woodward window function radiation pattern according to an embodiment of the present invention. The azimuth plane is a wide beam with a beamwidth of 90°. The elevation plane radiation pattern and the elevation plane direction of the main beam are also shown. Figure 1 Similarly, the gain of the azimuth beam widening beam is lower than that of the main beam.

[0036] like Figure 4 The diagram shown is a 6dB weighted amplitude difference elevation plane pattern with phase inversion window function according to an embodiment of the present invention. The elevation plane is a frequency sweep beam pattern after zero-depth elevation. The diagram also includes the azimuth plane pattern and the main beam azimuth plane pattern. Figure 1 Sample.

[0037] like Figure 5 The diagram shows the azimuth weighted Woodward window function radiation pattern and the elevation weighted amplitude difference (6 dB), and the vector synthesis of the phase-inverted window function radiation pattern. The azimuth plane is a wide beam with a beamwidth of 90°, and the elevation plane is the frequency sweep beam pattern after zero-depth elevation.

[0038] like Figure 6 The diagram shown is the shadow beam pattern of the phase-frequency swept antenna system according to an embodiment of the present invention. Figure 5 The radiation pattern after superimposing the main beam elevation difference radiation pattern onto the scalar radiation pattern.

[0039] An embodiment of the present invention is an active phase-frequency swept array antenna system operating in the Ku band. The azimuth plane has 120 elements, each connected to an active transceiver assembly. Receive beamforming is achieved through a deep beamforming (DBF). The elevation plane has 86 elements, divided into upper and lower sections to achieve frequency-sweeping monopulse. For example... Figure 7 The figure shows the difference between the radar beam and the stealth beam in an embodiment of the present invention. As can be seen from the figure, the radar beam is higher than the stealth beam in the main beam region and lower than the stealth beam in the sidelobe region, thus achieving the sidelobe stealth effect.

[0040] As can be seen from the simulation results of the embodiments of the present invention, the phase-frequency swept antenna system shadowing beam obtained by the present invention achieves the antenna sidelobe shadowing function without increasing hardware costs, enabling the radar system to suppress interference signals entering from the sidelobe region, improving the anti-interference performance of the radar system, and can serve as a reference for the formation of shadowing beams in other antenna systems.

[0041] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the scope of the technology disclosed in the present invention, and such modifications or substitutions should all be covered within the scope of protection of the present invention.

Claims

1. A method for implementing a sidelobe-masking beamformation of a phase-frequency swept monopulse antenna, characterized in that: Three beams are obtained by weighting different window functions. Then, the first and second beams are vector-synthesized to obtain a fourth beam. Finally, the fourth and third beams are scalar-superimposed to obtain the antenna system's stealth beam. The first beam is the antenna beam synthesized from the amplitude and phase results of the Woodward synthesis method, which uses weighted window functions to design the beamwidth at 90° for each element in the azimuth plane of the antenna system. The second beam is the antenna beam synthesized from the amplitude and phase weights of the upper and lower elements in the elevation plane of the antenna system, with an amplitude difference of 6dB and phase reversal. The third beam is the antenna beam synthesized from the amplitude and phase weights of the upper and lower elements in the elevation plane of the antenna system, with equal amplitude and phase reversal. Without changing or adding hardware, it is only necessary to give a set of feed amplitude and phase weights to make the antenna system form a specific beam, and then optimize the combination of different beams to achieve beam masking of the sidelobe region.

2. A computer system, characterized in that... include: One or more processors, a computer-readable storage medium for storing one or more programs, wherein, when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the method of claim 1.

3. A computer-readable storage medium, characterized in that... The device stores computer-executable instructions, which, when executed, are used to implement the method of claim 1.

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