A Phase-Only Weighted Beam Broadening Method

Abstract

The present invention provides a method for phase-weighted beam broadening only, the method comprising the following steps: S1: setting a phase broadening constant T, the phase broadening constant T has a value range of 1-10; S2: initializing a population and obtaining a phase weight function; S3: calculating the fitness of multiple populations in S2; S4: randomly selecting two populations for gene exchange to generate a new population; S5: performing a population mutation operation; S6: screening a population with the best fitness, calculating a corresponding phase weight, and using the phase weight to broaden the beam. The method for phase-weighted beam broadening only provided by the present invention can efficiently broaden the beam by a large multiple, so that the main lobe is relatively smooth after beam broadening, the phase change of adjacent radiating units is also relatively smooth, and the active standing wave of the radiating unit is small; the method can be applied to the field of active phased array radar antenna beamforming.

Description

Technical Field

[0001] The invention belongs to the technical field of phased array radar antennas, and in particular relates to a method for phase-weighted beam broadening only. Background Art

[0002] Since phased array antennas have flexible beam agility capabilities, radar systems require radar antennas to operate in a wide beam state when operating in multi-target search, tracking or guidance modes.

[0003] Beam broadening is to change the shape of the antenna pattern by changing various parameters of the phased array antenna to make it have a wider main lobe. The general method is to broaden the beam by phase weighting. The phase weight can be obtained by the square or cubic phase difference method, or by genetic algorithm (GA).

[0004] Although it is simple and easy to obtain phase weights by using the square or cubic phase difference method, it also has some limitations, such as the inability to efficiently widen the beam by a large multiple and it is difficult to take into account the needs of sidelobe level and efficiency.

[0005] Although the phase weights obtained by the genetic algorithm (GA) method can effectively widen the beam by a large multiple and take into account the sidelobe level and efficiency, the main lobe of the radiation pattern is sometimes not smooth, and the phase changes of adjacent radiating units are not smooth enough, and the active standing waves of some radiating units are large.

[0006] Therefore, it is necessary to provide a method for efficiently widening the beam by a large multiple, so that the main lobe is smoother after beam widening and the phase change of adjacent radiating units is also smoother. Summary of the invention

[0007] The present invention aims to solve the problems existing in the beam broadening method in the prior art.

[0008] The object of the present invention is to provide a method for phase-only weighted beam broadening, the method comprising the following steps:

[0009] S1: Set the phase broadening constant T, the phase broadening constant T value range is 1-10;

[0010] S2: Initialize the population and obtain the phase weight function;

[0011] S3: Calculate the fitness values ​​of multiple populations in S2;

[0012] S4: Randomly select two populations to exchange genes and generate new populations;

[0013] S5: perform population mutation operation;

[0014] S6: Filter the population with the best fitness, calculate the corresponding phase weight, and use the phase weight to broaden the beam.

[0015] The method for phase-weighted beam broadening only provided by the present invention also has the following characteristics: S2 comprises the following steps:

[0016] S2.1: Initialize the population, set the population size to P, and the number of elements in each population to N;

[0017] S2.2: Calculate the weights corresponding to the elements in the population, the nth power weight α n for:

[0018]

[0019] Among them, the value range of n is 1-N; L is the binary code length;

[0020] S2.3: Iteratively calculate the M0 phase weights of the population M0 is M / 2 rounded up, and M is the number of elements in the antenna array.

[0021] The phase-weighted beam broadening method provided by the present invention also has the following characteristics: the value range of the population number P is 50-100.

[0022] The method for phase-weighted beam broadening provided by the present invention also has the following characteristics: as follows:

[0023]

[0024] Among them, α n : The weight of the nth power;

[0025] m: represents the mth phase weight number, ranging from [1 to M0];

[0026] f n : Indicates whether the calculation result contains n-th power components, and the value is 0 or 1.

[0027] The method for phase-weighted beam broadening only provided by the present invention also has the following characteristics: S3 comprises the following steps:

[0028] S3.1: Calculate the power pattern corresponding to the first population, and calculate the corresponding beam width bw, the first sidelobe level sll, and the sidelobe mean meansll;

[0029] S3.2: Calculate the fitness value Fit of the population,

[0030] Fit=w1×abs(bw-BW)+w2×abs(sll-SLL)

[0031] +w3×abs(meansll-MEANSLL)

[0032] Where, BW: target beam width;

[0033] w1: target beam width weight in the fitness function;

[0034] SLL: target first sidelobe level;

[0035] W2: weight of the target first sidelobe level in the fitness function;

[0036] MEANSLL: target sidelobe mean;

[0037] W3: target sidelobe mean weight in fitness function;

[0038] S3.3: Calculate the fitness values ​​of all populations.

[0039] The method of phase-weighted beam broadening only provided by the present invention also has the following feature: in S3.2, when the amplitude is uniformly weighted, BW is not greater than 25°, then SLL takes a value of 11-15; when BW is greater than 25°, then SLL takes a value of 8-11.

[0040] The method for phase-weighted beam broadening only provided by the present invention also has the following characteristics: S4 comprises the following steps:

[0041] S4.1: Select new population;

[0042] S4.2: Select the number and position of genes for crossover. The number of genes should not be greater than half of the length of the binary code.

[0043] S4.3: Genes are exchanged between two populations to produce new populations after crossover.

[0044] The method for phase-weighted beam broadening only provided by the present invention also has the following characteristics: S5 comprises the following steps:

[0045] S5.1: Randomly select a population from the new population obtained in S4 to perform a mutation operation to obtain a mutated new population;

[0046] S5.2: Calculate the fitness value of the new population after the mutation. If the fitness value becomes better, keep the mutation, otherwise cancel the mutation;

[0047] S5.3: Perform 500-1000 iterations,

[0048] The phase-weighted beam broadening method provided by the present invention also has the following characteristics: the number of populations randomly selected to be mutated in S5.1 is no more than 1 / 4 of the number of elements in each population, and the number of genes to be mutated in each population to be mutated is no more than 3.

[0049] The method of phase-weighted beam broadening only provided by the present invention also has the following characteristics: in the population selection process, the initial selection probability of the population is 5%-15%. During the iteration process, if the optimal fitness value of the population remains unchanged for Q consecutive iterations, the selection probability increases in increments of 5% until the maximum selection probability is reached, wherein the value range of Q is 4-6, and the maximum selection probability is 80%.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The phase-weighted beam broadening method provided by the present invention can efficiently broaden the beam by a large multiple, so that the main lobe is relatively smooth after beam broadening, the phase change of adjacent radiating units is also relatively smooth, and the active standing wave of the radiating unit is small; this method can be applied to the field of active phased array radar antenna beamforming. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0053] Figure 1 : The directional diagram after broadening by the method of phase-weighted beam broadening only provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0054] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the following embodiments and accompanying drawings specifically illustrate the beam broadening method provided by the present invention.

[0055] In the description of the embodiments of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the invention.

[0056] In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0057] The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0058] A method for phase-only weighted beam broadening, the method comprising the following steps:

[0059] S1: Set the phase broadening constant T. The phase broadening constant T ranges from 1 to 10. The larger the phase broadening constant, the greater the beam broadening degree.

[0060] S2: Initialize the population and obtain the phase weight function:

[0061] S2.1: Initialize the population, set the population number to P, the number of elements in each population to N, and the value range of the population number P is 50-100;

[0062] S2.2: Calculate the weights corresponding to the elements in the population, the nth power weight α n for:

[0063]

[0064] Among them, the value range of n is 1-N; L is the binary code length;

[0065] S2.3: Iteratively calculate the M0 phase weights of the population M0 is M / 2 rounded up, M is the number of elements in the antenna array, and the mth phase weight as follows:

[0066]

[0067] Among them, α n : The weight of the nth power;

[0068] m: represents the mth phase weight number, ranging from [1 to M0];

[0069] f n: Indicates whether the calculation result contains the nth power component, the value is 0 or 1;

[0070] S3: Calculate the fitness values ​​of multiple populations in S2:

[0071] S3.1: Calculate the power pattern corresponding to the first population, and calculate the corresponding beam width bw, the first sidelobe level sll, and the sidelobe mean meansll;

[0072] S3.2: Calculate the fitness value Fit of the population,

[0073] Fit=w1×abs(bw-BW)+w2×abs(sll-SLL)

[0074] +w3×abs(meansll-MEANSLL)

[0075] Where, BW: target beam width;

[0076] w1: target beam width weight in the fitness function;

[0077] SLL: target first sidelobe level;

[0078] W2: weight of the target first sidelobe level in the fitness function;

[0079] MEANSLL: target sidelobe mean;

[0080] W3: target sidelobe mean weight in fitness function;

[0081] S3.3: Calculate the fitness values ​​of all populations;

[0082] S4: Randomly select two populations to exchange genes and generate new populations:

[0083] S4.1: Select new population;

[0084] S4.2: Select the number and position of genes for crossover. The number of genes should not be greater than half of the length of the binary code.

[0085] S4.3: Gene exchange between two populations to produce new populations after crossover;

[0086] S5: Perform population mutation operation:

[0087] S5.1: Randomly select a population from the new population obtained in S4 to perform a mutation operation to obtain a mutated new population;

[0088] S5.2: Calculate the fitness value of the new population after the mutation. If the fitness value becomes better, keep the mutation, otherwise cancel the mutation;

[0089] S5.3: Perform 500-1000 iterations;

[0090] S6: Filter the population with the best fitness, calculate the corresponding phase weight, and use the phase weight to broaden the beam.

[0091] In some embodiments, in S3.2, when the amplitude is uniformly weighted, BW is not greater than 25°, and SLL is 11-15; when BW is greater than 25°, SLL is 8-11.

[0092] In some embodiments, the number of populations randomly selected to be mutated in S5.1 is no more than 1 / 4 of the number of elements in each population, and the number of genes to be mutated in each population to be mutated is no more than 3.

[0093] In some embodiments, during the population selection process, the initial selection probability of the population is 5%-15%. During the iteration process, if the optimal fitness value of the population remains unchanged for Q consecutive iterations, the selection probability increases in increments of 5% until the maximum selection probability is reached, where the value range of Q is 4-6, and the maximum selection probability is 80%.

[0094] In some embodiments, the method is used to perform beam broadening on an azimuth plane for a phased array antenna:

[0095] The antenna contains 28 T / R channels. It is a pencil beam when receiving normally. At the center frequency, the 3dB beam width in azimuth is 3°. Due to the needs of the system, a beam with a 3dB beam width of 70° in azimuth is required. This method is used for design. The simulation pattern is as follows: Figure 1 As shown in the figure, after the beam is broadened by this method, the main lobe of the radiation pattern is relatively flat, and the top drop is small, only 0.7dB, which can meet the system requirements.

[0096] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A method of phase-weighted beam broadening only, characterized in that: The method comprises the following steps: S1: Set the phase broadening constant T. The phase broadening constant T ranges from 1 to 10. The larger the phase broadening constant, the greater the beam broadening. S2: Initialize the population and obtain the phase weight function; S3: Calculate the fitness values ​​of multiple populations in S2; S4: Randomly select two populations to exchange genes and generate new populations; S5: perform population mutation operation; S6: Filter the population with the best fitness, calculate the corresponding phase weight, and use the phase weight to widen the beam. The S2 comprises the following steps: S2.1: Initialize the population, set the population size to P, and the number of elements in each population to N; S2.2: Calculate the weights corresponding to the elements in the population, the nth power weight for: Among them, the value range of n is 1-N; L is the binary code length; S2.3: Iteratively calculate the M0 phase weights of the population , M0 is M / 2 rounded up, M is the number of elements in the antenna array, The population number P ranges from 50 to 100, and S3 includes the following steps: S3.1: Calculate the power pattern corresponding to the first population, and calculate the corresponding beam width bw, the first sidelobe level sll, and the sidelobe mean meansll; S3.2: Calculate the fitness value of the population , Where, BW: target beam width; : target beam width weight in the fitness function; : target first sidelobe level; : The weight of the target first sidelobe level in the fitness function; : target sidelobe mean; : The mean weight of the target side lobe in the fitness function; S3.3: Calculate the fitness value of all populations, The S4 comprises the following steps: S4.1: Select new population; S4.2: Select the number and position of genes for crossover. The number of genes should not be greater than half of the length of the binary code. S4.3: Gene exchange between two populations to produce new populations after crossover. The S5 comprises the following steps: S5.1: Randomly select a population from the new population obtained in S4 to perform a mutation operation to obtain a mutated new population; S5.2: Calculate the fitness value of the new population after the mutation. If the fitness value becomes better, keep the mutation, otherwise cancel the mutation; S5.3: Perform 500-1000 iterations.

2. The method of phase-weighted beam broadening according to claim 1, characterized in that: The mth phase weight in S2.3 as follows: in, : The weight of the nth power; m: represents the mth phase weight number, the value range is [1, M0]; : Indicates whether the calculation result contains n-th power components, and the value is 0 or 1.

3. The method of phase-weighted beam broadening according to claim 1, characterized in that: In S3.2, when the amplitude is uniformly weighted, if BW is not greater than 25°, the SLL value is 11 to 15; if BW is greater than 25°, the SLL value is 8 to 11.

4. The method of phase-weighted beam broadening only according to claim 1, characterized in that: The number of populations randomly selected to be mutated in S5.1 is no more than 1 / 4 of the number of elements in each population, and the number of genes to be mutated in each population to be mutated is no more than 3.

5. The method of phase-weighted beam broadening only according to claim 1, characterized in that: During the population selection process, the initial selection probability of the population is 5%-15%. During the iteration process, if the optimal fitness value of the population remains unchanged for Q consecutive iterations, the selection probability increases by 5% increments until the maximum selection probability is reached, where the value range of Q is 4-6, and the maximum selection probability is 80%.

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