CN105137398A - Genetic algorithm-based radar anti-forwarding-type interference pulse compression filter optimization method - Google Patents

Abstract

The invention discloses a genetic algorithm-based radar anti-forwarding-type interference pulse compression filter optimization method. The method mainly comprises steps: a transmitting signal and a forwarding-type interference signal are acquired, a genetic algorithm population size is set, an individual with the same size as the population size is generated randomly to serve as a pulse compression filter weight for a radar echo signal, a fitness function is further obtained, a variation probability, a crossover probability, the maximum evolutionary algebra and the maximum experiment times are obtained, filtering operation, crossover operation and variation operation are sequentially carried out on the individual with the same size as the population size respectively, the individual then serves as a final pulse compression filter weight for the radar echo signal, ratios of major to minor lobes after the final pulse compression filter weight for the radar echo signal is matched with the forwarding-type interference signal and the transmitting signal respectively are calculated, each obtained ratio of major to minor lobes can meet a corresponding ratio of major to minor lobes loss threshold setting requirement, the optimal pulse compression filter weight for the radar echo signal can be obtained, and the purposes can be realized.

Description

Optimizing method of pulse pressure filter for radar anti-repeat jamming based on genetic algorithm

technical field

The invention belongs to the technical field of radar waveform design, and in particular relates to a radar anti-transfer interference pulse pressure filter optimization method based on a genetic algorithm, which is suitable for solving the radar orthogonal emission caused by the incomplete orthogonality of the radar emission signal and the interference signal The problem of poor signal anti-interference ability makes the radar have stronger anti-interference ability, especially anti-repeat interference ability.

Background technique

Radar comes from English Radar, which is the abbreviation of Radio Detection and Ranging in English, meaning "radio detection and ranging", that is, using radio detection methods to find space targets and determine their spatial positions, making radar also known as "radio positioning". The radar transmits the electromagnetic wave energy generated by the transmitter antenna to a certain direction in space, and after being reflected by the target in this direction, the radar echo signal containing the target information and interference information is received by the receiver antenna, and then passed through The signal processing system processes the radar echo signal, extracts useful target information and filters out interference information, and then estimates useful target information, that is, target distance information, target azimuth information, target pitch information, and target speed information.

The transmission waveform of the radar not only determines the method of the signal processing system, but also directly affects the resolution, measurement accuracy and clutter suppression ability of the signal processing system. Therefore, the design of the radar transmission waveform is the best assessment object for the performance of the signal processing system, and Radar transmit waveform design has gradually become an important branch of modern radar theory. The radar emission waveform design is based on the target environment requirements and target information requirements. The target environment requirements are determined by the working environment of the radar where the target is located, and the target information requirements are determined by the signal type of the radar transmitted signal. Therefore, it is particularly important to select the appropriate signal type taking into account the difficulty of technical implementation. There are mainly two types of signals in the prior art, namely rectangular pulse signals and pulse compression signals.

The signal form of the rectangular pulse signal is single, that is, only "1" value, and the anti-interference ability is not good; in order to solve the contradiction between the mutual restriction between the radar range and the range resolution, it is necessary to find a more complex signal type, that is, the pulse compression signal , the pulse pressure process is mainly to measure the matching characteristics between the weight of the pulse pressure filter and the radar echo signal by using the ratio of the main and side lobe after the weight of the pulse pressure filter matches the radar echo signal. Commonly used pulse compression signals include: linear frequency modulation signal, non-linear frequency modulation signal and phase encoding signal.

The chirp signal is generally completely orthogonal to the two chirp signals generated based on the up-FM modulation and the down-FM modulation. The two chirp signals have a single form, and the orthogonal waveform generated is relatively fixed; the non-linear FM signal is used as the transmission signal Generally, the orthogonality of the two nonlinear FM signals generated based on the positive S-shaped FM curve and the inverted S-shaped FM curve is also very good. The two nonlinear FM signals have a single form, and the generated orthogonal waveforms are also relatively fixed. ; The signal encoding method of the phase-encoded signal is flexible and diverse, and the anti-intercept ability is strong, and when the signal is selected, the bandwidth is relatively small, the code length of the phase-encoded signal is short, it is not easy to detect, and it has good anti-interference ability, so choose Phase-encoded signals are used to design radar transmit waveforms.

The phase-encoded signal can be transmitted flexibly between pulses, and it can be transmitted between pulses immediately after intercepting the transmitted signal of the pulse, and then select two groups of signals from the multiple groups of signals obtained between each pulse, one of which is used as the transmitted signal, and the other group As a forwarding interference signal, the matching weight of the transmitted signal is used as the weight of the pulse pressure filter, and the transmission signal and the forwarding interference signal are not completely orthogonal, so that the weight of the pulse pressure filter and the transmission signal are completely match, but cannot suppress retransmitted interference.

At present, due to technical limitations and the actual complex background, it is impossible to find a transmitted signal with good orthogonality with the forwarding interference signal, and thus cannot suppress the forwarding interference. This problem has become an urgent problem to be solved.

Contents of the invention

For above deficiencies in the prior art, the object of the present invention is to propose a kind of radar anti-retransmission type interference pulse pressure filter optimization method based on genetic algorithm, according to the signal characteristic of transmission signal and retransmission type interference signal, optimize the radar echo signal The weight of the pulse pressure filter makes it match the transmitted signal to the greatest extent, and at the same time suppresses the repeating interference to the greatest extent.

The main idea of the present invention: first obtain the transmission signal and the forwarding interference signal, set the genetic algorithm population number, and randomly generate individuals with the same size as the genetic algorithm population number as the pulse pressure filter weight of the radar echo signal, and then After obtaining the fitness function, and setting the mutation probability, crossover probability, maximum evolution algebra, and maximum number of experiments, the individuals with the same size as the population of the genetic algorithm are subjected to the screening operation, crossover operation, and mutation operation in turn, and the radar echo The final weight of the pulse pressure filter of the signal, and calculate the main and side lobe ratio loss after the final weight of the pulse pressure filter of the radar echo signal is matched with the forwarding interference signal and the transmitted signal respectively, and the two main and side lobe ratios are calculated Satisfying the corresponding main and sidelobe ratio loss threshold setting requirements respectively, the optimal weight value of the pulse pressure filter of the radar echo signal can be obtained, and it can be matched with the transmitted signal to the greatest extent, and at the same time, the forwarding can be suppressed to the greatest extent. type interference, to achieve the purpose of the present invention.

In order to achieve the above-mentioned technical purpose, the present invention adopts the following technical solutions to achieve.

A kind of pulse pressure filter optimization method of radar anti-repeat type jamming based on genetic algorithm, it is characterized in that, comprises the following steps:

Step 1, obtain the transmission signal S_transmit and the forwarding interference signal S_interfere;

Step 2, set the maximum number of experiments maxtimes, the population number popsize of the genetic algorithm, and the mutation probability C, the crossover probability J and the maximum evolution algebra D in the genetic algorithm, and randomly generate different popsizes in the initial population G ⁱ of the i-th iterative experiment Individuals, and then popsize different individuals in the initial population G ⁱ of the i-th iterative experiment are used as the pulse pressure filter weights of the radar echo signal of the i-th iterative experiment Among them, the initial value of i is 1, i∈{1,2,…,maxtimes}, i represents the number of iterative experiments;

Step 3, according to the transmit signal S_transmit and the pulse pressure filter weight of the radar echo signal of the iterative experiment Construct the fitness function value MSR ⁱ of the i-th iterative experiment;

Step 4, according to the fitness function value MSR ⁱ of the iterative experiment, the final pulse pressure filter weight S_weight ⁱ of the radar echo signal after the iterative experiment is obtained through the genetic algorithm;

Step 5, respectively calculate the final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal after the i-th iterative experiment and the main-side lobe ratio MSR ⁱ _mutual after the matching of the transponder interference signal S_interfere, and after the i-th iterative experiment The main and side lobe ratio MSR ⁱ _owner after the pulse pressure filter final weight S_weight ⁱ of the radar echo signal is matched with the transmitted signal S_transmit;

If the calculated final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal after the i-th iterative experiment is matched with the main-side lobe ratio MSR ⁱ _mutual of the transponder interference signal S_interfere, and after the i-th iterative experiment After the final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal is matched with the transmitted signal S_transmit, the main-side lobe ratio MSR ⁱ _owner does not meet the corresponding main-side-lobe ratio loss threshold setting requirements, then increase i by 1, and return to the step 2;

If the calculated final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal after the i-th iterative experiment is matched with the main-side lobe ratio MSR ⁱ _mutual of the transponder interference signal S_interfere, and after the i-th iterative experiment After the final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal matches the transmitted signal S_transmit, the main-side lobe ratio MSR ⁱ _owner meets the corresponding main-side-lobe ratio loss threshold setting requirements, and the number of iterative experiments at this time i≤ maxtimes, the iterative experiment stops and proceeds to step 6;

Step 6, the final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal obtained after the iterative experiment is the optimal weight S_weight of the pulse pressure filter of the radar echo signal.

Compared with the prior art, the present invention has the following advantages:

(1) The method of the present invention can overcome the deficiency of the orthogonality between the forwarding interference signal and the pulse pressure filter weight, and by designing the optimal weight of the pulse pressure filter in the radar echo signal, the radar can be improved. Anti-jamming ability, especially anti-repeat interference ability;

(2) the method of the present invention adopts the genetic algorithm to make the optimal weight of the pulse pressure filter of the radar echo signal and the orthogonality of the transponder interference signal the best, and can realize the maximum degree of matching with the transmitted signal;

(3) The method of the present invention can optimize the search effect, increase the convergence speed, and greatly improve the timeliness by screening out the optimal weight of the pulse pressure filter in the required radar echo signal within a small number of iterations.

Description of drawings

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

Fig. 1 is a kind of schematic flow chart of the pulse pressure filter design method of the radar anti-transfer type interference based on genetic algorithm of the present invention;

Fig. 2 is a schematic diagram of the main-side lobe ratio after the pulse pressure filter weights of the transmitted signal and the radar echo signal are matched using the traditional method;

Fig. 3 is a schematic diagram of the main-side lobe ratio after matching the pulse pressure filter weight of the radar echo signal obtained by using the traditional method and the forwarding interference signal;

Fig. 4 is the main-side lobe ratio schematic diagram after the optimal weight value matching of the pulse pressure filter of the transmitted signal obtained by using the method of the present invention and the radar echo signal;

Fig. 5 is a schematic diagram of the main and side lobe ratio after matching the optimal weight of the pulse pressure filter of the radar echo signal obtained by using the method of the present invention and the repeating interference signal.

detailed description

Referring to Fig. 1, it is a schematic flow chart of a pulse pressure filter optimization method based on a genetic algorithm-based radar anti-transfer type interference of the present invention, and the pulse pressure filter optimization method of the radar anti-transfer type interference based on a genetic algorithm includes The following steps:

Step 1, acquire the transmit signal S_transmit and the forwarding interference signal S_interfere.

Specifically, the transmission signal S_transmit and the forwarding interference signal S_interfere of the current pulse are obtained, wherein the forwarding interference signal S_interfere is the transmission signal of the previous pulse;

The reason why the signal form of the transmitted signal S_transmit and the transponder interference signal S_interfere both choose the phase-encoded signal is that the encoding method of the phase-encoded signal is flexible and diverse, and the anti-interference ability and low interception ability are strong, so that the transmitted signal received between each pulse The forwarding is flexible, that is, once the transmitted signal is intercepted, the pulse-to-pulse forwarding is carried out immediately. Therefore, the transmitted signal of the previous pulse transmitted by the forwarding interference signal received by the current pulse of the radar, and the transmitted signal of the current pulse and the transmitted signal of the previous pulse If it is not perfectly orthogonal, the anti-repeat interference performance will be poor. To solve this problem, the present invention selects two groups of waveforms with slightly poorer orthogonality performance from multiple groups of orthogonal waveforms obtained between each pulse, one of which is used as a transmission signal, and the other group is used as an interference signal, namely S_transmit and S_interfere.

Step 2, set the maximum number of experiments maxtimes, the population number popsize of the genetic algorithm, and the mutation probability C, the crossover probability J and the maximum evolution algebra D in the genetic algorithm, and randomly generate different popsizes in the initial population G ⁱ of the i-th iterative experiment Individuals, and then popsize different individuals in the initial population G ⁱ of the i-th iterative experiment are used as the pulse pressure filter weights of the radar echo signal of the i-th iterative experiment Among them, the initial value of i is 1, i∈{1,2,...,maxtimes}, and i represents the number of iterative experiments.

Specifically, the radar echo signal includes transmission signal, forwarding interference signal and noise, after the radar echo signal is passed through the pulse pressure filter, the pulse pressure filter weight value of the radar echo signal is generated, and then the radar echo signal The weight of the pulse pressure filter is matched with the radar echo signal, and then the recognition, detection and positioning of the target can be realized. When there is a forwarding interference signal in the radar echo signal, and the orthogonality between the forwarding interference signal and the transmitted signal is not good, it may cause a great impact on the identification, detection and positioning of the target, so the optimization of the radar echo signal The weight of the pulse pressure filter becomes particularly important.

Step 3, according to the transmit signal S_transmit and the pulse pressure filter weight of the radar echo signal of the iterative experiment Construct the fitness function value MSR ⁱ of the i-th iterative experiment; where, the initial value of i is 1, i represents the number of iterative experiments, i∈{1,2,...,maxtimes}, and maxtimes represents the maximum number of experiments set.

Specifically, according to the transmitted signal S_transmit and the pulse pressure filter weight of the radar echo signal of the i-th iteration experiment Construct the fitness function value MSR ⁱ of the i-th iterative experiment, and its expression is:

MSR ⁱ = max(S_match ⁱ +λ/(S_orth ⁱ +ε));

Among them, S_match ⁱ represents the pulse pressure filter weight of the transmitted signal S_transmit and the radar echo signal of the iterative experiment The matched main-sidelobe ratio,

and S_orth ⁱ represents the forwarding interference signal S_interfere and the pulse pressure filter weight of the radar echo signal of the iterative experiment The matched main-to-sidelobe ratio, and

ε represents the pulse pressure filter weight to prevent the forwarding interference signal S_interfere and the radar echo signal of the iterative experiment The main and sidelobe ratio S_orth ⁱ after matching is a very small number of zero, the present invention takes ε=0.0000001, and λ represents the pulse pressure filter weight of the radar echo signal controlling the forwarding interference signal S_interfere and the iterative experiment of the ith time The order of magnitude parameter of the main-side lobe ratio S_orth ⁱ after matching can generally take 0.1 or 1 or 10, and the present invention takes λ=1, Pmsr ( ) represents asking for the main-side lobe ratio, conv ( ) represents seeking convolution, S_transmit Indicates the transmitted signal, Indicates the pulse pressure filter weight of the radar echo signal obtained in the i-th iterative experiment, max( ) means to take the maximum value, the initial value of i is 1, i∈{1,2,...,maxtimes}, maxtimes means The maximum number of experiments set, i represents the number of iterative experiments.

The purpose of obtaining the fitness function value is to optimize the pulse pressure filter weight of the radar echo signal, so that it can match the transmitted signal to the greatest extent, and at the same time suppress the forward interference in the radar echo signal to the greatest extent; the fitness function value The size of is mainly determined by the main-side lobe ratio after the pulse pressure filter weights of the transmitted signal and the radar echo signal are matched, and the main-side lobe ratio after the pulse pressure filter weights of the forwarding interference signal and the radar echo signal are matched. jointly determined; the larger the main-side lobe ratio after the matching of the pulse pressure filter weights of the transmitted signal and the radar echo signal, the better the matching characteristics of the pulse pressure filter weights of the transmitted signal and the radar echo signal; The smaller the main-sidelobe ratio after matching the pulse pressure filter weights of the interference signal and the radar echo signal, the poorer the matching between the pulse pressure filter weights of the radar echo signal and the forwarding interference signal, and the orthogonality the better.

In order to optimize the pulse pressure filter weight of the radar echo signal, so that it can match the transmitted signal to the greatest extent, and at the same time suppress the forward interference in the radar echo signal to the greatest extent, that is, to maximize the value of the fitness function, then It is required that the main-side lobe ratio after matching the pulse pressure filter weights of the transmitted signal and the radar echo signal is as large as possible, and the main-side lobe ratio after the pulse pressure filter weight matching of the forwarding interference signal and the radar echo signal is as large as possible. It may be small to achieve the purpose of optimizing the pulse pressure filter weight of the radar echo signal.

Step 4, according to the fitness function value MSR ⁱ of the i-th iterative experiment, the final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal after the i-th iterative experiment is obtained through the genetic algorithm; where, the initial value of i is 1, i represents the number of iterative experiments, i∈{1,2,...,maxtimes}, maxtimes represents the maximum number of experiments set.

The specific sub-steps of step 4 are as follows:

4.1 Let the initial population G ⁱ of the first evolutionary algebra of the i-th iterative experiment be G ⁱ¹ , and then use the genetic algorithm to perform the screening operation, crossover operation, and mutation operation on the popsize individuals in G ⁱ¹ respectively to obtain m ¹ different mutant individuals; among them, m ¹ <popsize;

Let the number of the intermediate population of the jth generation be M ^j , put m ¹ different mutant individuals and popsize different individuals in G ⁱ¹ in the first generation intermediate population M ¹ , and then from the first generation intermediate population M ¹ Select popsize different individuals closest to the fitness function MSR ⁱ of the i-th iterative experiment as the initial population G ⁱ² of the second-generation evolutionary algebra of the i-th iterative experiment, j∈{1,2,…,D }, D represents the maximum evolution algebra set;

4.2 Use the genetic algorithm to perform the screening operation, crossover operation, and mutation operation on the popsize different individuals in G ⁱ² respectively to obtain m ² mutant individuals;

Put the m ² mutant individuals and the popsize different individuals in G ⁱ² in the second-generation intermediate population M ² , and then select the fitness function closest to the iterative experiment from the second-generation intermediate population M ² The popsize different individuals of MSR ⁱ are used as the initial population G ⁱ³ of the iterative experiment of the third generation evolutionary algebra, j∈{1,2,...,D}, D represents the maximum evolutionary algebra set;

4.3 Repeat this process, use the genetic algorithm to obtain the popsize different individuals in G ^ij of the j-th evolutionary algebra of the iterative experiment in the iterative experiment, and then perform the screening operation, crossover operation, and mutation on the popsize different individuals in G ^ij respectively. Operation, get m ^j mutant individuals, j∈{1,2,…,D}, D represents the maximum evolution algebra set;

Put the m ^j mutant individuals and the popsize different individuals in G ^ij in the j-th generation intermediate population M ^j , and then select the fitness function closest to the iterative experiment from the j-th generation intermediate population M ^j The popsize different individuals of MSR ⁱ , as the initial population G ^i(j+1) of the j+1th generation evolutionary algebra of the i-th iterative experiment, j∈{1,2,…,D}, j+1∈ {1,2,...,D}, D represents the maximum evolution algebra set;

Until the initial population G ^iD of the D-th evolutionary generation of the iterative experiment is obtained, the iteration stops. At this time, the popsize different individuals in G ^iD are used as the radar echo after the iterative experiment obtained by the genetic algorithm The final weight S_weight i of the pulse pressure filter of the signal, that is, the final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal after the ⁱ -th iterative experiment is obtained through the genetic algorithm;

Among them, the initial value of i is 1, i represents the number of iterative experiments, i∈{1,2,…,maxtimes}, maxtimes represents the maximum number of experiments set, and popsize represents the number of genetic algorithm populations set.

Specifically, the screening operation is based on the optimal value of the fitness function of the i-th iterative experiment as a criterion, to select the population of the popsize different individuals in the i-th iterative experiment that is closest to the value of the fitness function of the i-th iterative experiment The result, that is, the initial value of the pulse pressure filter weight of the radar echo signal selected from the i-th iterative experiment Among the popsize individuals, l different individuals that are closest to the value of the fitness function; l≤popsize, popsize represents the number of genetic algorithm populations set.

The crossover operation is to randomly select two different individuals among the l different individuals in the i-th iterative experiment to perform the crossover operation, and obtain m different new individuals. in, l represents the number of different individuals closest to the fitness function of the iterative experiment, Indicates to obtain permutations and combinations, and There are many ways of crossover operation, generally including single-point crossover and multi-point crossover. For example, for two individuals 11110 and 00101, perform crossover at the second position to obtain two new individuals as 11101 and 00110.

The mutation operation is to perform a bitwise mutation operation on m different new individuals, that is, for each new individual among the m different new individuals, randomly select the tth bit to perform the mutation operation, and obtain m different mutant individuals. Among them, t∈{1,2,...,T}, T represents the number of digits of each new individual among m different new individuals. For example, for a new individual 00110, randomly select the third digit for mutation operation, and the obtained mutant individual is 00010, calculate the fitness function values of m different mutant individuals respectively, and obtain m different fitness values of the iterative experiment The best individual corresponding to the function value is used as the pulse pressure filter weight S_weight ⁱ of the final radar echo signal obtained by the genetic algorithm after the i-th iterative experiment; where, the initial value of i is 1, and i represents the number of iterative experiments, i∈{1,2,…,maxtimes}, maxtimes represents the maximum number of experiments set.

Step 5, respectively calculate the final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal after the i-th iterative experiment and the main-side lobe ratio MSR ⁱ _mutual after the matching of the transponder interference signal S_interfere, and after the i-th iterative experiment The main and side lobe ratio MSR ⁱ _owner after the pulse pressure filter final weight S_weight ⁱ of the radar echo signal is matched with the transmitted signal S_transmit;

If the calculated final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal after the i-th iterative experiment is matched with the main-side lobe ratio MSR ⁱ _mutual of the transponder interference signal S_interfere, and after the i-th iterative experiment After the final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal is matched with the transmitted signal S_transmit, the main-side lobe ratio MSR ⁱ _owner does not meet the corresponding main-side-lobe ratio loss threshold setting requirements, then increase i by 1, and return to the step 2;

If the calculated final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal after the i-th iterative experiment is matched with the main-side lobe ratio MSR ⁱ _mutual of the transponder interference signal S_interfere, and after the i-th iterative experiment After the final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal matches the transmitted signal S_transmit, the main-side lobe ratio MSR ⁱ _owner meets the corresponding main-side-lobe ratio loss threshold setting requirements, and the number of iterative experiments at this time i≤ maxtimes, the iterative experiment stops, and proceed to step 6; where the initial value of i is 1, i represents the number of iterative experiments, i∈{1,2,...,maxtimes}, and maxtimes represents the maximum number of experiments set.

Specifically, the main-to-sidelobe ratio of the pulse pressure filter final weight S_weight ⁱ of the radar echo signal after the i-th iterative experiment is matched with the repeating interference signal S_interfere can be expressed as MSR ⁱ _mutual , and its expression is:

MSR ⁱ _mutual = Pmsr(conv(conj(fliplr(S_weight ⁱ )),S_interfere))

Among them, Pmsr(·) represents the ratio of main and side lobe, conv(·) represents convolution, conj(·) represents conjugation, fliplr(·) represents value inversion, S_weight ⁱ represents after the iterative experiment The final weight of the pulse pressure filter of the radar echo signal, S_interfere represents the forwarding interference signal.

The main and side lobe ratio loss threshold after the matching of the pulse pressure filter final weight S_weight ⁱ of the radar echo signal after the i-th iterative experiment and the forwarding interference signal S_interfere is expressed as Threshold_orth, and the smaller the Threshold_orth is set, the i-th The better the orthogonality between the pulse pressure filter final weight S_weight ⁱ of the radar echo signal after the iterative experiment and the forwarding interference signal S_interfere, Threshold_orth is not higher than 0.5dB in the present invention;

Moreover, after the i-th iterative experiment, the final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal matches the transmitted signal S_transmit and the main-side lobe ratio can be expressed as MSR ⁱ _owner , and its expression is:

MSR ⁱ _owner = Pmsr(conv(S_transmit, conj(fliplr(S_weight ⁱ )))),

Among them, Pmsr(·) represents the ratio of main and side lobe, conv(·) represents convolution, conj(·) represents conjugation, fliplr(·) represents value inversion, S_weight ⁱ represents after the iterative experiment The pulse pressure filter weight of the final radar echo signal, S_transmit represents the transmitted signal.

The final weight of the pulse pressure filter S_weight ⁱ of the radar echo signal after the i-th iterative experiment is matched with the transmission signal S_transmit The loss threshold of the main-side lobe ratio is expressed as Threshold_loss, and the larger the Threshold_loss is set, it indicates that the transmission signal S_transmit and the i-th The better the matching characteristic of the final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal after the second iterative experiment, the threshold_loss is set by the present invention to not exceed 2dB.

Step 6, the final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal obtained after the iterative experiment is the optimal weight S_weight of the pulse pressure filter of the radar echo signal; where, the initial value of i is 1, i represents the number of iterative experiments, i∈{1,2,...,maxtimes}, maxtimes represents the maximum number of experiments set.

Specifically, the final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal obtained after the iterative experiment is the optimal weight S_weight of the pulse pressure filter of the radar echo signal, and then calculate the radar echo signal The main-side lobe ratio Msr1 after the optimal weight S_weight of the pulse pressure filter is matched with the transmitted signal S_transmit, and the main-side lobe ratio after the optimal weight S_weight of the pulse pressure filter of the radar echo signal is matched with the forwarding interference signal S_interfere Msr2, its calculation formulas are:

Msr1=Pmsr(conv(S_transmit,S_weight))

Msr2=Pmsr(conv(S_interfere,S_weight))

Among them, Pmsr(·) represents the ratio of the main and side lobe, conv(·) represents the convolution, conj(·) represents the conjugation, fliplr(·) represents the value inversion, S_transmit represents the transmitted signal, S_interfere represents the forwarding type Jamming signal.

The effects of the present invention can be further illustrated by the following simulation experiments.

(1) Simulation conditions

Both the transmit signal S_transmit and the transponder interference signal S_interfere are phase-encoded signals with a code length of 40, set the population number popsize=20 in the genetic algorithm, and set the maximum number of experiments maxtimes=1000 to prevent the transponder interfering signal S_interfere and the ith time The final weight of the pulse pressure filter weight of the radar echo signal of the iterative experiment The matched main-sidelobe ratio is a very small number ε=0.0000001, which controls the final weight of the pulse pressure filter of the forwarding interference signal S_interfere and the radar echo signal of the i-th iterative experiment The magnitude parameter of the matched main-sidelobe ratio is λ=1, i represents the number of iterative experiments, the initial value of i is 1, and i∈{1,2,…,1000}.

The transmission signal S_transmit has good matching characteristics with the pulse pressure filter weight of the radar echo signal obtained by the traditional method and the transmission signal S_transmit, but the orthogonality with the forwarding interference signal S_interfere is not very good, and its side lobe is The main lobe has a greater influence. In order to improve the anti-interference ability, the optimal weight S_weight of the pulse pressure filter of the radar echo signal is obtained by using the method of the present invention, and at the same time, the transponder interference is suppressed to the greatest extent.

(2) Simulation results and analysis

Figure 2 is a schematic diagram of the main and side lobe ratios after matching the pulse pressure filter weights of the transmitted signal and the radar echo signal obtained by using the traditional method; from Figure 2, it can be seen that the transmitted signal S_transmit with a code length of 40 and the transponder interference The signal S_interfere can be obtained by using the traditional method to obtain the pulse pressure filter weight of the radar echo signal and the transmission signal S_transmit. The main-side lobe ratio MSR _owner is 15.0515dB.

Figure 3 is a schematic diagram of the main-side lobe ratio after the pulse pressure filter weight of the radar echo signal obtained by using the traditional method and the forwarding interference signal are matched; as can be seen from Figure 3, the pulse pressure filter weight of the radar echo signal and The main-to-sidelobe ratio MSR _mutual after forwarding interference matching is 1.2094dB;

There is a certain matching characteristic between the forwarding interference signal S_interfere and the transmitting signal S_transmit, that is, the orthogonality is not very good; when the anti-transferring interference requirements cannot be met, the traditional method is to use the pulse pressure filter weight of the radar echo signal It is convolved with the transponder interference signal S_interfere, but the main and side lobes after the matching of the pulse pressure filter weight of the radar echo signal and the transponder interference signal S_interfere are relatively high, which cannot achieve the purpose of anti-transfer interference.

The traditional method is to calculate the final weight of the pulse pressure filter of the radar echo signal under the premise of sacrificing a small amount of transmitted signal S_transmit and the weight of the pulse pressure filter of the radar echo signal to match the main and sidelobe ratio, and the obtained radar echo The final weight of the pulse pressure filter of the wave signal and the transmitted signal S_transmit can achieve the maximum degree of matching, and the orthogonality between the final weight of the pulse pressure filter of the radar echo signal and the forwarding interference signal S_interfere is relatively good, thereby achieving anti- Forward interference purposes.

The present invention adopts the genetic algorithm, sets the maximum number of evolutions as 100 generations, the number of populations as 20, the crossover probability as 0.7, the mutation probability as 0.12, the maximum number of experiments as 1000 times, and respectively sets the final pulse pressure filter weight and The main-side lobe ratio loss threshold after the transmitted signal is matched is 2dB, the final pulse pressure filter weight of the radar echo signal is matched with the transponder interference signal, and the main-side lobe ratio loss threshold is 0.3dB. The optimal weight of the pulse pressure filter of the wave signal, that is, the final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal in the i-th iterative experiment is matched with the main-sidelobe ratio of the transmitted signal S_transmit, and the i-th Whether the main and side lobe ratios of the pulse pressure filter final weight S_weight ⁱ of the radar echo signal and the forwarding interference signal S_interfere in the iterative experiment meet the corresponding main and side lobe ratio loss threshold setting requirements.

When the calculated two main-sidelobe ratios meet the corresponding main-sidelobe ratio loss threshold setting requirements, the optimal weight of the pulse pressure filter of the radar echo signal can be obtained, and the pulse pressure of the radar echo signal can be verified. The optimal weight of the filter and the matching characteristics of the transmitted signal, and the orthogonality between the optimal weight of the pulse pressure filter of the radar echo signal and the transponder interference signal. Among them, i represents the number of iterative experiments, the initial value of i is 1, and i∈{1,2,…,1000}.

Fig. 4 is the main-side lobe ratio schematic diagram after the optimal weight value matching of the pulse pressure filter of the transmitted signal obtained by the method of the present invention and the radar echo signal, and Fig. 5 is the pulse pressure of the radar echo signal obtained by the method of the present invention Schematic diagram of the main-side lobe ratio after the optimal weight of the filter is matched with the forwarding interference signal.

It can be seen from both Figure 4 and Figure 5 that the main and side lobe ratio Msr1 after matching the optimal weight S_weight of the pulse pressure filter of the final radar echo signal and the transmitted signal S_transmit is: 13.3468, and the final radar echo The main-side-lobe ratio Msr2 after the match between the signal pulse pressure filter optimal weight S_weight and the repeating interference signal S_interfere is: 0.1072dB. It can be seen that the optimal weight S_weight of the pulse pressure filter of the radar echo signal obtained as the optimal matching weight for suppressing forward interference is similar to the weight of the pulse pressure filter of the radar echo signal obtained by the traditional method. Ratio, the loss value is less than 2dB, but its orthogonality has been greatly improved, and its anti-repeat interference performance has also been greatly improved.

In summary, the simulation experiment has verified the correctness, effectiveness and reliability of the present invention.

Obviously, those skilled in the art can carry out various modifications and variations to the present invention without departing from the spirit and scope of the present invention; Like this, if these modifications and variations of the present invention belong to the scope of the claims of the present invention and equivalent technologies thereof, It is intended that the present invention also encompasses such changes and modifications.

Claims (7)

1. a kind of pulse pressure filter optimization method based on the radar anti-transfer type jamming of genetic algorithm, is characterized in that, comprises the following steps: Step 1, obtain the transmission signal S_transmit and the forwarding interference signal S_interfere; Step 2, set the maximum number of experiments maxtimes, the population number popsize of the genetic algorithm, and the mutation probability C, the crossover probability J and the maximum evolution algebra D in the genetic algorithm, and randomly generate different popsizes in the initial population G ⁱ of the i-th iterative experiment Individuals, and then popsize different individuals in the initial population G ⁱ of the i-th iterative experiment are used as the pulse pressure filter weights of the radar echo signal of the i-th iterative experiment Among them, the initial value of i is 1, i∈{1,2,…,maxtimes}, i represents the number of iterative experiments; Step 3, according to the transmit signal S_transmit and the pulse pressure filter weight of the radar echo signal of the iterative experiment Construct the fitness function value MSR ⁱ of the i-th iterative experiment; Step 4, according to the fitness function value MSR ⁱ of the iterative experiment, the final pulse pressure filter weight S_weight ⁱ of the radar echo signal after the iterative experiment is obtained through the genetic algorithm; Step 5, respectively calculate the final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal after the i-th iterative experiment and the main-side lobe ratio MSR ⁱ _mutual after the matching of the transponder interference signal S_interfere, and after the i-th iterative experiment The main and side lobe ratio MSR ⁱ _owner after the pulse pressure filter final weight S_weight ⁱ of the radar echo signal is matched with the transmitted signal S_transmit; If the calculated final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal after the i-th iterative experiment is matched with the main-side lobe ratio MSR ⁱ _mutual of the transponder interference signal S_interfere, and after the i-th iterative experiment After the final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal is matched with the transmitted signal S_transmit, the main-side lobe ratio MSR ⁱ _owner does not meet the corresponding main-side-lobe ratio loss threshold setting requirements, then increase i by 1, and return to the step 2; If the calculated final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal after the i-th iterative experiment is matched with the main-side lobe ratio MSR ⁱ _mutual of the transponder interference signal S_interfere, and after the i-th iterative experiment After the final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal matches the transmitted signal S_transmit, the main-side lobe ratio MSR ⁱ _owner meets the corresponding main-side-lobe ratio loss threshold setting requirements, and the number of iterative experiments at this time i≤ maxtimes, the iterative experiment stops and proceeds to step 6; Step 6, the final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal obtained after the iterative experiment is the optimal weight S_weight of the pulse pressure filter of the radar echo signal. 2. the pulse pressure filter optimization method of a kind of radar anti-repeating type jamming based on genetic algorithm as claimed in claim 1, is characterized in that, in step 3, the fitness function numerical value MSR of described i iterative experiment ⁱ , whose expression is: MSR ⁱ = max(S_match ⁱ +λ/(S_orth ⁱ +ε)) Among them, S_match ⁱ represents the pulse pressure filter weight of the transmitted signal S_transmit and the radar echo signal of the iterative experiment The main and side lobe ratio after matching, S_orth ⁱ represents the pulse pressure filter weight of the forwarding interference signal S_interfere and the radar echo signal of the iterative experiment The main and side lobe ratio after matching, ε represents the pulse pressure filter weight to prevent the forwarding interference signal S_interfere and the radar echo signal of the iterative experiment The matched main-sidelobe ratio S_orth ⁱ is a very small number of zero, and λ represents the weight of the pulse pressure filter that controls the retransmitting interference signal S_interfere and the radar echo signal of the iterative experiment The magnitude parameter of the matched main and side lobe ratio S_orth ⁱ , Indicates the pulse pressure filter weight of the radar echo signal obtained in the i-th iterative experiment, max(·) indicates the maximum value, the initial value of i is 1, i indicates the number of iterative experiments, i∈{1,2,… ,maxtimes}, maxtimes represents the maximum number of experiments set. 3. the pulse pressure filter optimization method of a kind of radar anti-repeating type interference based on genetic algorithm as claimed in claim 2, it is characterized in that, the radar echo of described control retransmission type interference signal S_interfere and i iterative experiment The pulse pressure filter weight of the signal The magnitude parameter λ=1 of the matched main and sidelobe ratio S_orth ⁱ ; where the initial value of i is 1, i represents the number of iterative experiments, i∈{1,2,...,maxtimes}, and maxtimes represents the maximum number of experiments set . 4. the pulse pressure filter optimization method of a kind of radar anti-repeating type interference based on genetic algorithm as claimed in claim 2, is characterized in that, described prevents the radar echo of retransmission type interference signal S_interfere and the iterative experiment of i The pulse pressure filter weight of the signal The matched main and side lobe ratio S_orth ⁱ is a very small number ε=0.0000001; where the initial value of i is 1, i represents the number of iterative experiments, i∈{1,2,...,maxtimes}, maxtimes represents the set Maximum number of experiments. 5. A kind of pulse pressure filter optimization method of radar anti-transfer interference based on genetic algorithm as claimed in claim 1, is characterized in that, in step 5, described respective corresponding loss threshold setting requirements, specifically refer to The final weight S_weight ⁱ of the pulse pressure filter of the radar echo signal after the iterative experiment is matched with the transponder interference signal S_interfere. The setting of the main-side lobe ratio loss threshold requires Threshold_orth, and the radar after the iterative experiment The final weight S_weight ⁱ of the pulse pressure filter of the echo signal matches the transmission signal S_transmit. The setting of the main-side lobe ratio loss threshold requires Threshold_loss, and sets Threshold_orth not higher than 0.5dB, Threshold_loss not exceeding 2dB; where, the initial value of i is 1, i represents the number of iterative experiments, i∈{1,2,...,maxtimes}, and maxtimes represents the maximum number of experiments set. 6. the pulse pressure filter optimization method of a kind of radar anti-repeat type interference based on genetic algorithm as claimed in claim 1, is characterized in that, in step 5, the radar echo signal after described i iterative experiment The main and side lobe ratio MSR _mutual after the final weight S_weight ⁱ of the pulse pressure filter matches the forwarding interference signal S_interfere, its expression is: MSR ⁱ _mutual = Pmsr(conv(conj(fliplr(S_weight ⁱ )),S_interfere)) Among them, Pmsr(·) represents the ratio of main and side lobe, conv(·) represents convolution, conj(·) represents conjugation, fliplr(·) represents value inversion, S_weight ⁱ represents after the iterative experiment The final weight of the pulse pressure filter of the radar echo signal, S_interfere represents the forwarding interference signal, the initial value of i is 1, i represents the number of iterative experiments, i∈{1,2,...,maxtimes}, maxtimes represents the set Maximum number of experiments. 7. the pulse pressure filter optimization method of a kind of radar anti-repeating type interference based on genetic algorithm as claimed in claim 1, is characterized in that, in step 5, the radar echo signal after the iterative experiment of described i The main and side lobe ratio MSR ⁱ _owner after the final weight S_weight ⁱ of the pulse pressure filter is matched with the transmitted signal S_transmit, its expression is: MSR ⁱ _owner = Pmsr(conv(S_transmit, conj(fliplr(S_weight ⁱ )))), Among them, Pmsr(·) represents the ratio of main and side lobe, conv(·) represents convolution, conj(·) represents conjugation, fliplr(·) represents value inversion, S_weight ⁱ represents after the iterative experiment The pulse pressure filter weight of the final radar echo signal, S_transmit represents the transmitted signal, the initial value of i is 1, i represents the number of iterative experiments, i∈{1,2,...,maxtimes}, maxtimes represents the maximum experiment set frequency.