A method for optimizing the pattern side lobe level based on multi-channel DBF

Abstract

The application discloses a pattern side lobe level optimization method based on a multi-channel DBF, and comprises the following steps: step S1, for the designed antenna array layout, the theoretical Taylor weighting coefficient is calculated; step S2, the Taylor weighting coefficient of the current iteration is solidified into the phased array seeker for pattern test; step S3, according to the pattern test result after adding the Taylor weighting coefficient, the antenna array element causing the side lobe level higher than the first side lobe level after the first side lobe of the pattern is analyzed, and the Taylor weighting coefficient is optimized by comprehensively considering the whole antenna array; step S4, the optimized Taylor weighting coefficient is verified to determine whether it meets the product pattern performance requirement; if it meets the product pattern performance requirement, step S5 is executed; otherwise, return to step S2 and continue the loop iteration; step S5, the Taylor weighting coefficient meeting the product requirement is solidified into the product. The application has high flexibility, high optimization compensation precision and high universality.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of antennas, and particularly relates to a pattern sidelobe level optimization method based on a multi-channel DBF. BACKGROUND

[0002] With the development of science and technology, the mechanical scanning form of radar seeker antenna is increasingly difficult to adapt to the real-time tracking of high-speed moving target systems, and phased array antennas replace mechanical scanning through electric control scanning, thereby improving the tracking speed of the antenna on the target system and being the development direction of the current radar antenna. In the prior art, with the increasingly wide application of phased array systems, the sidelobe level has become a very important index. The ratio of the maximum value of the sidelobe to the maximum value of the main lobe is called the sidelobe level, which is generally expressed in dB, for example, if the ratio of the maximum value of the sidelobe to the corresponding power of the maximum value of the main lobe is 0.01, then the sidelobe level is -20 dB. The smaller the main lobe width is, the more sharp the pattern is, and the more concentrated the antenna radiation is. Therefore, the sidelobe level determines the anti-interference and anti-clutter capabilities of a phased array system to a great extent, and is closely related to the tactical and technical indexes of the phased array system.

[0003] In the article "Optimization Design of Airborne Radar Antenna Pattern" published by Ni Chun and Wu Xianliang of Anhui University, a genetic algorithm is used to optimize the lobe width, sidelobe level and weighted efficiency, and the specific steps are as follows: coding and initialization, 8-bit binary coding is used for the weighted phase of each array element, a group of phases forms a chromosome, and the number of initial chromosomes is 100; selection of the adaptive function, analyzing the pattern characteristics corresponding to each chromosome, and constructing the objective function according to the contents to be optimized; crossover and mutation; and cycle until the pattern meets the optimization condition.

[0004] The genetic algorithm is a self-adaptive global optimization search algorithm simulating the genetic and evolution process of organisms in the natural environment. Although the article "Optimization Design of Airborne Radar Antenna Pattern" can effectively optimize the lobe width, sidelobe level and weighted efficiency, the pattern optimization algorithm based on the genetic algorithm is relatively complex, and with the increase of the number of antenna elements, the sample learning number of the genetic algorithm increases, the calculation amount increases, and the cycle iteration period becomes longer, which is limited in engineering applications. SUMMARY

[0005] To solve the above technical problems, the application provides a pattern sidelobe level optimization method based on a multi-channel DBF.

[0006] The application is implemented through the following technical solutions.

[0007] The application provides a pattern sidelobe level optimization method based on a multi-channel DBF, which comprises the following steps:

[0008] Step S1, for the designed antenna array layout, the theoretical Taylor weighting coefficient is calculated correspondingly;

[0009] Step S2, the Taylor weighting coefficient of the current iteration is solidified into the phased array seeker for pattern test;

[0010] Step S3, according to the pattern test result after adding the Taylor weighting coefficient, the antenna array element whose side lobe level is higher than the first side lobe level is analyzed, the whole antenna array is analyzed, and the Taylor weighting coefficient is optimized;

[0011] Step S4, the optimized Taylor weighting coefficient is solidified into the phased array seeker for verification, and it is judged whether it meets the product pattern performance requirement; if it meets the product pattern performance requirement, step S5 is executed; otherwise, it returns to step S2 and continues to iterate;

[0012] Step S5, the Taylor weighting coefficient meeting the product requirement is solidified into the product.

[0013] Preferably, in step S1, after the array radius a and the distance p of each antenna element relative to the center are obtained for the designed antenna array layout, the theoretical Taylor weighting coefficient is calculated correspondingly, which is calculated according to the following expression:

[0014]

[0015] Wherein, p is the distance of each antenna element relative to the center, a is the array radius; J0 is the 0th Bessel function; γ 1m is the root of the first order Bessel function J1(πγ 1m )=0;

[0016]

[0017] A is the amplitude, and s is the lobe spread factor.

[0018] Preferably, in step S2, the pattern test refers to the receiving pattern test standard under the far field condition of the active phased array antenna.

[0019] Preferably, in step S3, the Taylor weighting coefficient is optimized, and the optimization criterion is:

[0020] The amplitude coefficient of the antenna element corresponding to the high side lobe level is reduced, and the amplitude coefficient of the antenna element corresponding to the low first side lobe level is improved, while the overall symmetry and performance index of the antenna pattern are met;

[0021] The performance index requirement includes the main side lobe ratio and the antenna gain.

[0022] Preferably, the step S4 meets the product direction pattern performance requirement, that is, according to the analysis of the optimized Taylor weighting coefficient based on the correlation array index, it is ensured that the space domain sidelobe interference suppression capability of the product meets the requirement after the Taylor weighting coefficient is solidified in the product.

[0023] Preferably, the correlation array index includes the main beam width, the main sidelobe ratio and the direction pattern symmetry in the direction pattern.

[0024] The beneficial effects of the present application are as follows:

[0025] 1. The advantages of the multi-channel DBF phased array antenna are fully utilized, the optimization of the antenna sidelobe level is completely realized by the digital compensation mode, and the optimization is flexible and variable.

[0026] 2. The design criterion of the Taylor weighting coefficient is derived from the antenna array layout, the optimization basis is derived from the measured results of the antenna direction pattern, and the optimization effect can be accurately verified through the iterative test of the antenna direction pattern, and the optimization compensation precision is high.

[0027] 3. The proposed antenna sidelobe level optimization method can be applied not only to the missile-borne multi-channel DBF phased array radar seeker, but also to the ground phased array radar system, and has strong universality. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a method flowchart of the present application;

[0029] Figure 2 is a comparison chart of the Taylor weighting coefficient before and after optimization of the present application. DETAILED DESCRIPTION

[0030] The technical solutions of the present application are further described below, but the scope of protection is not limited to the description.

[0031] As shown in Figure 1 , a direction pattern sidelobe level optimization method based on multi-channel DBF, characterized by comprising the following steps:

[0032] Step S1, for the designed antenna array layout, the theoretical Taylor weighting coefficient is calculated correspondingly;

[0033] In the step S1, for the designed antenna array layout, after the array radius a and the distance p of each antenna element relative to the center are obtained, the theoretical Taylor weighting coefficient is calculated correspondingly, and the calculation is performed according to the following expression:

[0034]

[0035] wherein, p is the distance of each antenna element relative to the center, a is the array radius, J0 is the 0th Bessel function, and y is the Taylor weighting coefficient.1m is a root of the first Bessel function J1 (πγ 1m ) = 0;

[0036]

[0037] A is the amplitude, and σ is the lobe spread factor.

[0038] Step S2, solidify the Taylor weighting coefficient of the current iteration into the phased array seeker for pattern test;

[0039] The pattern test in step S2 refers to the receiving pattern test standard under the far field condition of the active phased array antenna.

[0040] Due to the amplitude inconsistency difference between the multi-channel phased array seeker antenna units and the radio frequency channels, and the assembly difference caused by the product assembly process, the side lobe level after the first side lobe of the antenna pattern will be obviously higher than the first side lobe level.

[0041] Step S3, according to the pattern test result after adding the Taylor weighting coefficient, analyze the antenna elements that cause the side lobe level after the first side lobe of the antenna pattern to be higher than the first side lobe level, analyze the entire antenna array, and optimize the Taylor weighting coefficient;

[0042] The Taylor weighting coefficient is optimized in step S3, and the optimization criterion is:

[0043] Lower the amplitude coefficient of the antenna unit corresponding to the high side lobe level, and correspondingly improve the amplitude coefficient of the antenna unit corresponding to the low first side lobe level, while meeting the overall symmetry and performance index requirements of the antenna pattern;

[0044] Meet the overall symmetry of the antenna pattern to ensure the performance index of the antenna.

[0045] Step S4, solidify the optimized Taylor weighting coefficient into the phased array seeker for verification to determine whether it meets the product pattern performance requirements; if it meets the product pattern performance requirements, execute step S5; otherwise, return to step S2 and continue to iterate;

[0046] The product pattern performance requirement in step S4 means that the optimized Taylor weighting coefficient is analyzed according to the related array index to ensure that the spatial side lobe interference suppression capability of the product meets the requirements after the Taylor weighting coefficient is solidified into the product.

[0047] The related array index includes the main lobe width, the main side lobe ratio, and the pattern symmetry in the pattern.

[0048] Step S5, solidify the Taylor weighting coefficient meeting the product requirements into the product.

[0049] Compared with the prior art, the present application aims at the problem that the post side lobe level of the pattern of the missile-borne multi-channel DBF phased array radar seeker is higher than the first side lobe level, resulting in poor space domain side lobe interference suppression capability, adopts the Taylor weighting coefficient optimization algorithm based on the multi-channel DBF and the all-digital compensation approach, can further reduce the first side lobe level and ensure the symmetry of the pattern, improve the space domain side lobe anti-interference capability of the phased array radar seeker, and the patterns before and after the optimization of the antenna side lobe level are as shown in Figure 2 The first side lobe level of the multi-channel DBF phased array radar seeker can be improved by 5 dB through the Taylor weighting coefficient optimization.

Claims

1. A method for optimizing pattern sidelobe levels based on multi-channel DBF, characterized in that: Includes the following steps: Step S1: Calculate the theoretical Taylor weighting coefficients for the designed antenna array layout; Step S2: Solidify the Taylor weighting coefficients of the current iteration into the phased array seeker for pattern testing; Step S3: Based on the radiation pattern test results after adding Taylor weighting coefficients, analyze the antenna elements that cause the sidelobe level after the first sidelobe of the radiation pattern to be higher than the first sidelobe level, analyze the entire antenna array, and optimize the Taylor weighting coefficients. Step S4: Solidify the optimized Taylor weighting coefficients into the phased array seeker for verification to determine whether they meet the product pattern performance requirements; if they meet the product pattern performance requirements, proceed to step S5. Otherwise, return to step S2 and continue the loop iteration; Step S5: Solidify the Taylor weighted coefficients that meet the product requirements into the product; In step S1, the array radius is obtained based on the designed antenna array layout. Distance between each antenna element and its center Then, the theoretical Taylor weighting coefficients are calculated according to the following expression: in, , The distance of each antenna element relative to the center, The radius of the array; It is a 0th-order Bessel function; First-order Bessel function The root; , , For amplitude, This is the lobe broadening factor; In step S3, the Taylor weighting coefficients are optimized, and the optimization criteria are as follows: Reduce the amplitude coefficient of the antenna element that causes high sidelobe level, and correspondingly increase the amplitude coefficient of the antenna element that causes low first sidelobe level, while meeting the overall symmetry of the antenna pattern and performance requirements. The performance requirements include the main lobe-to-side lobe ratio and antenna gain.

2. The method for optimizing pattern sidelobe levels based on multi-channel DBF as described in claim 1, characterized in that: In step S2, the radiation pattern test is performed in accordance with the test standard for receiving radiation pattern under far-field conditions of active phased array antennas.

3. The method for optimizing the sidelobe level of a radiation pattern based on multi-channel DBF as described in claim 1, characterized in that: In step S4, meeting the product radiation pattern performance requirements means that, based on the analysis of relevant array indicators, the optimized Taylor weighting coefficients are used to ensure that the product's spatial sidelobe interference suppression capability meets the requirements after the Taylor weighting coefficients are solidified into the product.

4. The method for optimizing the sidelobe level of a pattern based on multi-channel DBF as described in claim 3, characterized in that: The relevant array parameters include the main beamwidth, main-to-side lobe ratio, and pattern symmetry in the radiation pattern.

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