Directional diagram sidelobe level optimization method based on multi-channel DBF

Abstract

The invention discloses a directional diagram sidelobe level optimization method based on a multichannel DBF, and the method comprises the following steps: S1, correspondingly calculating a theoretical Taylor weighting coefficient for a designed antenna array layout; step S2, solidifying the current iterative Taylor weighting coefficient into the phased array seeker to carry out a directional diagram test; s3, according to a test result of the directional diagram after the Taylor weighting coefficient is added, analyzing an antenna array element which causes a sidelobe level after a first sidelobe of the directional diagram to be higher than a first sidelobe level, comprehensively considering the whole antenna array, and optimizing the Taylor weighting coefficient; s4, verifying the optimized Taylor weighting coefficient, and judging whether the optimized Taylor weighting coefficient meets the performance requirements of a product directional diagram or not; if the product pattern performance requirements are met, executing the step S5; otherwise, returning to the step S2, and continuing loop iteration; and S5, solidifying the Taylor weighting coefficient meeting the product requirement into the product. The method is high in flexibility, high in optimization compensation precision and high in universality.

Description

Technical Field

[0001] The invention belongs to the technical field of antennas, and in particular relates to a method for optimizing a directional pattern sidelobe level based on a multi-channel DBF. Background Art

[0002] With the development of science and technology, mechanical scanning radar seeker antennas are increasingly difficult to adapt to real-time tracking of high-speed moving target systems. Phased array antennas use electronic scanning instead of mechanical scanning to improve the tracking speed of the antenna to the target system, which is also the current development direction of radar antennas. In the prior art, with the increasing application of phased array systems, the sidelobe level has become a very important indicator. Among them, 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 corresponding power of the maximum value of the sidelobe to the maximum value of the main lobe is 0.01, then the sidelobe level is -20dB. The smaller the main lobe width, the sharper the radiation pattern, indicating that the antenna radiation is more concentrated. Therefore, the sidelobe level largely determines the anti-interference and anti-clutter capabilities of a phased array system, and is also closely related to the tactics and technical indicators of the phased array system.

[0003] In the paper "Optimization Design of Airborne Radar Antenna Pattern" published by Ni Chun and Wu Xianliang from Anhui University, genetic algorithm was used to optimize the lobe width, sidelobe level and weighted efficiency. The specific steps are as follows: encoding and initialization, using 8-bit binary encoding for the weighted phase of each array element, a group of phases constitutes a chromosome, and the initial number of chromosomes is 100; selection of adaptation function, analysis of the pattern characteristics corresponding to each chromosome, and construction of the objective function based on the content to be optimized; crossover and mutation; loop until the pattern meets the optimization conditions.

[0004] Genetic algorithm is an adaptive global optimization search algorithm formed by simulating the genetic and evolutionary process of organisms in the natural environment. Although the article "Optimization Design of Airborne Radar Antenna Pattern" can effectively optimize the beam width, sidelobe level and weighted efficiency, the pattern optimization algorithm based on genetic algorithm itself is relatively complex. Moreover, with the increase of antenna array elements, the number of sample learning of genetic algorithm increases, the amount of calculation increases, and the cycle of loop iteration becomes longer, which limits its application in engineering. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for optimizing the sidelobe level of a directional pattern based on a multi-channel DBF.

[0006] The present invention is achieved through the following technical solutions.

[0007] The present invention provides a method for optimizing the sidelobe level of a directional pattern based on a multi-channel DBF, comprising the following steps:

[0008] Step S1, calculating theoretical Taylor weighting coefficients corresponding to the designed antenna array layout;

[0009] Step S2, solidifying the Taylor weighting coefficient of the current iteration into the phased array seeker to perform a pattern test;

[0010] Step S3, according to the test result of the directional pattern after adding the Taylor weighting coefficient, analyzing the antenna array element that causes the sidelobe level after the first sidelobe of the directional pattern to be higher than the first sidelobe level, analyzing the entire antenna array, and optimizing the Taylor weighting coefficient;

[0011] 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 the loop iteration;

[0012] Step S5: solidify the Taylor weighting coefficient that meets the product requirements into the product.

[0013] Preferably, in step S1, for the designed antenna array layout, after obtaining the array radius a and the distance ρ of each antenna unit relative to the center, the theoretical Taylor weighting coefficient is calculated accordingly, and the calculation is performed according to the following expression:

[0014]

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

[0016]

[0017] A is the amplitude and σ is the lobe broadening factor.

[0018] Preferably, the pattern test performed in step S2 refers to a receiving pattern test standard under far-field conditions for an active phased array antenna.

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

[0020] Reduce the amplitude coefficient of the antenna unit that causes the high sidelobe level, and correspondingly increase the amplitude coefficient of the antenna unit that causes the low first sidelobe level, while meeting the overall symmetry and performance index requirements of the antenna pattern;

[0021] The performance index requirements include main-to-sidelobe ratio and antenna gain.

[0022] Preferably, satisfying the product pattern performance requirements in step S4 refers to analyzing and optimizing the Taylor weighting coefficients according to relevant array indicators to ensure that the spatial sidelobe interference suppression capability of the product meets the requirements after the Taylor weighting coefficients are solidified into the product.

[0023] Preferably, the relevant array indicators include main beam width, main-to-side lobe ratio, and symmetry of the pattern.

[0024] The beneficial effects of the present invention are:

[0025] 1. Make full use of the advantages of multi-channel DBF phased array antennas. The optimization of antenna sidelobe level is completely realized through digital compensation, which is flexible and variable;

[0026] 2. The design criteria of Taylor weighting coefficients are derived from the antenna array layout, and the basis for optimization is derived from the measured results of the antenna pattern. The optimization effect can be accurately verified through iterative testing of the antenna pattern, and the optimization compensation accuracy is high;

[0027] 3. The proposed antenna sidelobe level optimization method is not only applicable to missile-borne multi-channel DBF phased array radar seekers, but also to ground-based phased array radar systems, with strong versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a flow chart of the method of the present invention;

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

[0030] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0031] like Figure 1 As shown, a method for optimizing the sidelobe level of a directional pattern based on a multi-channel DBF is characterized by comprising the following steps:

[0032] Step S1, calculating theoretical Taylor weighting coefficients corresponding to the designed antenna array layout;

[0033] In step S1, for the designed antenna array layout, after obtaining the array radius a and the distance ρ of each antenna unit relative to the center, the theoretical Taylor weighting coefficient is calculated accordingly, and the calculation is performed according to the following expression:

[0034]

[0035] in, ρ is the distance of each antenna unit relative to the center, a is the array radius; J0 is the 0th order Bessel function; γ1m is the first-order Bessel function J1(πγ 1m ) = the root of 0;

[0036]

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

[0038] Step S2, solidifying the Taylor weighting coefficient of the current iteration into the phased array seeker to perform a pattern test;

[0039] The pattern test performed in step S2 refers to the receiving pattern test standard under far-field conditions of active phased array antennas.

[0040] Due to the amplitude inconsistency differences between the multi-channel phased array seeker antenna units and RF channels, as well as the assembly differences caused by the product assembly process, the sidelobe level after the first sidelobe of the antenna pattern will be significantly higher than the first sidelobe level.

[0041] Step S3, according to the test result of the directional pattern after adding the Taylor weighting coefficient, analyzing the antenna array element that causes the sidelobe level after the first sidelobe of the directional pattern to be higher than the first sidelobe level, analyzing the entire antenna array, and optimizing the Taylor weighting coefficient;

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

[0043] Reduce the amplitude coefficient of the antenna unit that causes the high sidelobe level, and correspondingly increase the amplitude coefficient of the antenna unit that causes the low first sidelobe level, while meeting the overall symmetry and performance index requirements of the antenna pattern;

[0044] The overall symmetry of the antenna pattern is met to ensure the antenna performance indicators.

[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 the loop iteration;

[0046] Meeting the product pattern performance requirements in step S4 refers to analyzing and optimizing the Taylor weighting coefficients according to relevant array indicators to ensure that the spatial sidelobe interference suppression capability of the product meets the requirements after the Taylor weighting coefficients are solidified into the product.

[0047] The relevant array indicators include the main beam width, the main-to-side lobe ratio, and the symmetry of the pattern.

[0048] Step S5: solidify the Taylor weighting coefficient that meets the product requirements into the product.

[0049] Compared with the existing technology, the present invention aims at the problem that the level of the rear sidelobe of the missile-borne multi-channel DBF phased array radar seeker directional pattern is higher than the level of the first sidelobe, resulting in poor spatial sidelobe interference suppression capability. The Taylor weighted coefficient optimization algorithm based on multi-channel DBF and the approach of full digital compensation can further reduce the first sidelobe level and ensure the symmetry of the directional pattern, thereby improving the spatial sidelobe anti-interference capability of the phased array radar seeker. The directional pattern before and after the optimization of the antenna sidelobe level is as follows: Figure 2 As shown in the figure, by optimizing the Taylor weighting coefficient, the first sidelobe level of the multi-channel DBF phased array radar seeker can be improved by 5dB.

Claims

1. A method for optimizing the sidelobe level of a directional pattern based on multi-channel DBF, characterized in that: The following steps are involved: Step S1, calculating theoretical Taylor weighting coefficients corresponding to the designed antenna array layout; Step S2, solidifying the Taylor weighting coefficient of the current iteration into the phased array seeker to perform a pattern test; Step S3, according to the test result of the directional pattern after adding the Taylor weighting coefficient, analyzing the antenna array element that causes the sidelobe level after the first sidelobe of the directional pattern to be higher than the first sidelobe level, analyzing the entire antenna array, and optimizing the Taylor weighting coefficient; Step S4, solidifying 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, executing step S5; Otherwise, return to step S2 and continue loop iteration; Step S5: solidify the Taylor weighting coefficient that meets the product requirements into the product.

2. A method for optimizing the directional pattern sidelobe level based on multi-channel DBF as claimed in claim 1, characterized in that: In step S1, for the designed antenna array layout, after obtaining the array radius a and the distance ρ of each antenna unit relative to the center, the theoretical Taylor weighting coefficient is calculated accordingly, and the calculation is performed according to the following expression: in, ρ is the distance of each antenna unit relative to the center, a is the array radius; J0 is the 0th order Bessel function; γ 1m is the first-order Bessel function J1(πγ 1m ) = the root of 0; A is the amplitude and σ is the lobe broadening factor.

3. A method for optimizing the directional pattern sidelobe level based on multi-channel DBF as claimed in claim 1, characterized in that: The pattern test performed in step S2 refers to the receiving pattern test standard under far-field conditions of active phased array antennas.

4. A method for optimizing the directional pattern sidelobe level based on multi-channel DBF as claimed in claim 1, characterized in that: In step S3, the Taylor weighting coefficient is optimized, and the optimization criterion is: Reduce the amplitude coefficient of the antenna unit that causes the high sidelobe level, and correspondingly increase the amplitude coefficient of the antenna unit that causes the low first sidelobe level, while meeting the overall symmetry and performance index requirements of the antenna pattern; The performance index requirements include main-to-sidelobe ratio and antenna gain.

5. A method for optimizing the directional pattern sidelobe level based on multi-channel DBF as claimed in claim 1, characterized in that: Meeting the product pattern performance requirements in step S4 refers to analyzing and optimizing the Taylor weighting coefficients according to relevant array indicators to ensure that the spatial sidelobe interference suppression capability of the product meets the requirements after the Taylor weighting coefficients are solidified into the product.

6. A method for optimizing the directional pattern sidelobe level based on multi-channel DBF as claimed in claim 5, characterized in that: The relevant array indicators include the main beam width, the main-to-side lobe ratio, and the symmetry of the pattern.

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