Non-cooperative radar emitter pulse repetition interval modulation period estimation method and system

Abstract

This invention proposes a method and system for estimating the modulation period of pulse repetition intervals for non-cooperative radar sources, belonging to the fields of signal processing and radar data analysis. The method includes: statistically analyzing the frequency and pulse width of the received radar data to remove abnormal data, and establishing an initial histogram based on the pulse repetition interval; merging adjacent statistical intervals smaller than a preset threshold using the mean difference of the statistical intervals; calculating a multi-order time difference sequence of pulse arrival times; extracting the effective pulse frame length based on typical values ​​of the multi-order time difference sequence; and estimating the modulation period of the pulse repetition interval using the greatest common divisor of the effective pulse frame length difference sequence. This invention does not require prior information on the pulse repetition interval modulation type and can achieve rapid and accurate estimation of the modulation period of pulse repetition intervals for non-cooperative radar sources under conditions of low signal-to-noise ratio and high pulse loss rate.

Description

Technical Field

[0001] This invention belongs to the field of signal processing and radar data analysis technology, and particularly relates to a method and system for estimating the pulse repetition interval modulation period of a non-cooperative radar radiation source. Background Technology

[0002] An important aspect of radar reconnaissance data analysis is extracting the patterns and characteristics of radar radiation sources, such as frequency, pulse width, repetition interval, and antenna scanning, in order to obtain the typical signal patterns of radar radiation sources. This lays the foundation for subsequent radar radiation source type identification, individual identification, and operating mode identification, and is an important research direction in the field of electronic warfare.

[0003] The pulse repetition interval of a radar emitter refers to the first-order difference in the arrival times of two adjacent radar pulses. It is closely related to the radar's range detection capability, velocity detection capability, and anti-jamming performance, making it the most important signal parameter of a radar emitter and a key focus of radar reconnaissance data analysis. Furthermore, because the modulation type of the pulse repetition interval is highly correlated with the radar emitter's operating mode, it is crucial for establishing a radar emitter target database and assessing the threat level of radar emitters and their platforms. Therefore, the analysis of typical values ​​for radar emitter pulse repetition intervals and the identification of modulation types are currently paramount in radar signal parameter analysis.

[0004] However, with increasingly complex electromagnetic environments and more advanced radar source systems, coupled with limitations in reconnaissance equipment performance and personnel capabilities, problems such as low signal-to-noise ratio and high pulse loss rate in reconnaissance data are becoming increasingly severe. Under high pulse loss rates, directly identifying the pulse repetition interval modulation type of radar sources using time characteristic maps is almost impossible. However, unlike the typical value of the pulse repetition interval, the pulse repetition interval modulation period is a significant feature that remains relatively stable even under high pulse loss conditions. Therefore, estimating the pulse repetition interval modulation period first, followed by pulse sample sub-map reconstruction and pulse repetition interval modulation feature analysis, represents a novel research approach. Consequently, there is an urgent need to develop an efficient method for estimating the pulse repetition interval modulation period of radar sources, especially when prior information about the pulse repetition interval is unavailable. How to quickly and accurately estimate the pulse repetition interval modulation period of non-cooperative radar sources is a critical technology that urgently needs to be addressed. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a method and system for estimating the pulse repetition interval modulation period of a non-cooperative radar source by extracting the effective frame length of the pulse using a multi-order time difference sequence of the pulse repetition interval and pulse arrival time. This method enables rapid and accurate estimation of the pulse repetition interval modulation period of a non-cooperative radar source under conditions of low signal-to-noise ratio and high pulse loss rate, without requiring prior information on the pulse repetition interval modulation type.

[0006] The first aspect of this invention proposes a method for estimating the modulation period of pulse repetition intervals from non-cooperative radar radiation sources. The method includes:

[0007] Step S1: Perform statistical analysis on the frequency and pulse width of the radar received data to remove abnormal pulses in the radar received data and establish a histogram of the pulse repetition interval sequence.

[0008] Step S2: Calculate the mean difference of pulse repetition intervals between adjacent statistical intervals, and compare the mean difference with the decision threshold to merge adjacent statistical intervals that meet the conditions;

[0009] Step S3: Determine the maximum order of time difference based on the number of effective intervals and the pulse sequence length, and calculate the corresponding multi-order time difference sequence using the pulse arrival time;

[0010] Step S4: Calculate the typical value and occurrence number of the multi-order time difference sequence of pulse arrival time. Delete the typical value of the multi-order time difference sequence whose occurrence number is less than a preset threshold to obtain an effective pulse frame length vector.

[0011] Step S5: Perform differential operation on the effective pulse frame length vector, and obtain the pulse repetition interval modulation period of the non-cooperative radar radiation source by solving its greatest common divisor.

[0012] According to the method of the first aspect of the present invention, in step S1, the frequency and pulse width of the radar received data are statistically analyzed, pulses exceeding the conventional value and preset range are discarded, and the pulse repetition interval is calculated according to the pulse arrival time.

[0013] Δt k =t k+1 -t k ,1≤k≤K-1

[0014] Among them, t k Let K be the arrival time of the k-th pulse, and K be the total number of detected pulses.

[0015] Calculate the maximum value of the pulse repetition interval sequence. and minimum value And set the discretization interval Δt for the statistical interval of the pulse repetition interval sequence;

[0016] Statistical analysis is performed on each pulse repetition interval to construct a histogram of the pulse repetition interval sequence.

[0017] According to the method of the first aspect of the present invention, in step S2, the mean difference of the pulse repetition interval between adjacent statistical intervals is calculated:

[0018] Δx n =x n+1 -x n ,1≤n≤N′-1

[0019] Where, x n N represents the average pulse repetition interval within the nth statistical interval, and N′ represents the total number of statistical intervals.

[0020] Compare the mean difference with the decision threshold:

[0021] Δx n ≤0.7Δt

[0022] If Δx n If ≤0.7Δt holds, then the pulse repetition intervals of two adjacent statistical intervals are merged; otherwise, the mean difference of pulse repetition intervals in subsequent adjacent statistical intervals is calculated, and the judgment and merging operations are continuously performed until the analysis of all statistical intervals is completed. The final number of valid statistical intervals is recorded as N.

[0023] According to the method of the first aspect of the present invention, in step S3, the maximum order P of the time difference is determined based on the number N of effective intervals and the pulse sequence length:

[0024] P = min{100N, S⁻¹}

[0025] Where S represents the length of the pulse sequence after removing outliers;

[0026] Solve for pulse arrival time difference sequences of different orders:

[0027]

[0028] According to the method of the first aspect of the present invention, in step S4:

[0029] Histogram statistics were performed on the obtained multi-order pulse arrival time difference sequences to obtain the statistical characteristic parameters x = [x1, x2, ..., x...]. L ] and y = [y1, y2, ..., y L ], where L is the number of typical values, x l For the l-th typical value of the pulse time difference sequence, y l The number of occurrences of the l-th typical value;

[0030] Sort y in descending order, and starting from y2, determine whether the element should be kept. If the element is equal to or greater than 2 / 3 of the average of all preceding elements, keep the element and continue searching. If the element is less than 2 / 3 of the average of all preceding elements, stop searching and delete all elements after the element.

[0031] Synchronously delete the corresponding typical values ​​in x. The remaining typical values ​​in x are the effective pulse frame lengths, which are defined as a new vector. The number of elements is M.

[0032] According to the method of the first aspect of the present invention, in step S5, the vector is... Sort the elements in ascending order to obtain the vector x′=[x′1,x′2,…,x′]. M ] Calculate the difference in the effective frame length of the pulse:

[0033] Δx m =|x′ m+1 -x′ m |,m=1,2,…,M-1

[0034] Solve the sequence Δx m The greatest common divisor ΔT is used to obtain the pulse repetition interval modulation period of the non-cooperative radar radiation source.

[0035] A second aspect of this invention provides a system for estimating the modulation period of a non-cooperative radar radiation source pulse repetition interval. The system includes:

[0036] The first processing unit is configured to: perform statistical analysis on the frequency and pulse width of the radar received data to remove abnormal pulses in the radar received data, and establish a histogram of the pulse repetition interval sequence.

[0037] The second processing unit is configured to: calculate the mean difference of pulse repetition intervals between adjacent statistical intervals, compare the mean difference with a decision threshold, and merge adjacent statistical intervals that meet the conditions;

[0038] The third processing unit is configured to: determine the maximum order of time difference based on the number of effective intervals and the pulse sequence length, and calculate the corresponding multi-order time difference sequence using the pulse arrival time;

[0039] The fourth processing unit is configured to: calculate the typical value and the number of occurrences of the multi-order time difference sequence of pulse arrival time, and delete the typical values ​​of the multi-order time difference sequence whose number of occurrences is less than a preset threshold, so as to obtain an effective pulse frame length vector.

[0040] The fifth processing unit is configured to perform differential operations on the effective pulse frame length vector and obtain the pulse repetition interval modulation period of the non-cooperative radar radiation source by solving its greatest common divisor.

[0041] According to the system of the second aspect of the present invention, the first processing unit is specifically configured to: perform statistical analysis on the frequency and pulse width of the radar received data, perform a rejection operation on pulses that exceed the normal value and preset range, and calculate the pulse repetition interval according to the pulse arrival time.

[0042] Δt k =t k+1 -t k ,1≤k≤K-1

[0043] Among them, t k Let K be the arrival time of the k-th pulse, and K be the total number of detected pulses.

[0044] Calculate the maximum value of the pulse repetition interval sequence. and minimum value And set the discretization interval Δt for the statistical interval of the pulse repetition interval sequence;

[0045] Statistical analysis is performed on each pulse repetition interval to construct a histogram of the pulse repetition interval sequence.

[0046] According to the system of the second aspect of the present invention, the second processing unit is specifically configured to: calculate the mean difference between the pulse repetition intervals of adjacent statistical intervals:

[0047] Δx n =x n+1 -x n ,1≤n≤N′-1

[0048] Where, x n N represents the average pulse repetition interval within the nth statistical interval, and N′ represents the total number of statistical intervals.

[0049] Compare the mean difference with the decision threshold:

[0050] Δx n ≤0.7Δt

[0051] If Δx n If ≤0.7Δt holds, then the pulse repetition intervals of two adjacent statistical intervals are merged; otherwise, the mean difference of pulse repetition intervals in subsequent adjacent statistical intervals is calculated, and the judgment and merging operations are continuously performed until the analysis of all statistical intervals is completed. The final number of valid statistical intervals is recorded as N.

[0052] According to the system of the second aspect of the present invention, the third processing unit is specifically configured to: determine the maximum order P of the time difference based on the number N of effective intervals and the pulse sequence length.

[0053] P = min{100N, S⁻¹}

[0054] Where S represents the length of the pulse sequence after removing outliers;

[0055] Solve for pulse arrival time difference sequences of different orders:

[0056]

[0057] According to the system of the second aspect of the present invention, the fourth processing unit is specifically configured to: perform histogram statistics on the obtained multi-order pulse arrival time difference sequence to obtain the statistical characteristic parameter x = [x1, x2, ..., x...] of the multi-order time difference sequence. L ] and y = [y1, y2, ..., y L ], where L is the number of typical values, x l For the l-th typical value of the pulse time difference sequence, y l The number of occurrences of the l-th typical value;

[0058] Sort y in descending order, and starting from y2, determine whether the element should be kept. If the element is equal to or greater than 2 / 3 of the average of all preceding elements, keep the element and continue searching. If the element is less than 2 / 3 of the average of all preceding elements, stop searching and delete all elements after the element.

[0059] Synchronously delete the corresponding typical values ​​in x. The remaining typical values ​​in x are the effective pulse frame lengths, which are defined as a new vector. The number of elements is M.

[0060] According to the system of the second aspect of the present invention, the fifth processing unit is specifically configured to: process vectors Sort the elements in ascending order to obtain the vector x′=[x′1,x′2,…,x′]. M ] Calculate the difference in the effective frame length of the pulse:

[0061] Δx m =|x′ m+1 -x′ m |,m=1,2,…,M-1

[0062] Solve the sequence Δx m The greatest common divisor ΔT is used to obtain the pulse repetition interval modulation period of the non-cooperative radar radiation source.

[0063] A third aspect of this invention discloses an electronic device. The electronic device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps in the method for estimating the modulation period of a non-cooperative radar radiation source pulse repetition interval as described in the first aspect of this disclosure.

[0064] A fourth aspect of this invention discloses a computer-readable storage medium. The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps in the method for estimating the modulation period of a non-cooperative radar radiation source pulse repetition interval as described in the first aspect of this disclosure.

[0065] In summary, this invention addresses the technical challenge of poor accuracy in estimating the pulse repetition interval modulation period of non-cooperative radar sources under conditions of low signal-to-noise ratio and high pulse loss rate. First, it establishes an initial histogram of the pulse repetition interval for the non-cooperative radar source and merges adjacent statistical intervals whose mean difference is less than the discretization interval, thereby reducing the dispersion effect caused by the discretization interval. Then, it calculates the multi-order time difference sequence of pulse arrival times and extracts the effective pulse frame length. Finally, it estimates the pulse repetition interval modulation period of the non-cooperative radar source by solving for the greatest common divisor. This invention requires no prior information about the pulse repetition interval modulation type and can achieve rapid and accurate estimation of the pulse repetition interval modulation period of non-cooperative radar sources.

[0066] The estimation results of the pulse repetition interval modulation period of non-cooperative radar radiation sources provided by this invention can offer technical support for radar radiation source sorting. Using the estimated period provided by this invention for frame screening, multiple typical values ​​of pulse repetition intervals can be identified simultaneously. Therefore, the batch processing of radar radiation sources can be effectively reduced, improving the processing efficiency of radar reconnaissance data.

[0067] The estimation results of the pulse repetition interval modulation period of non-cooperative radar radiation sources in this invention can be used to reconstruct radar pulse sample sub-maps with high accuracy under conditions of low signal-to-noise ratio and high pulse loss rate. It can provide favorable support for the identification of pulse repetition interval modulation type of non-cooperative radar radiation sources, target type identification, and target operating mode identification. Attached Figure Description

[0068] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0069] Figure 1This is a flowchart of a method for estimating the modulation period of a non-cooperative radar radiation source pulse repetition interval according to an embodiment of the present invention.

[0070] Figure 2 This is a structural diagram of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0071] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0072] The first aspect of this invention proposes a method for estimating the modulation period of pulse repetition intervals from non-cooperative radar radiation sources. The method includes:

[0073] Step S1: Perform statistical analysis on the frequency and pulse width of the radar received data to remove abnormal pulses in the radar received data and establish a histogram of the pulse repetition interval sequence.

[0074] Step S2: Calculate the mean difference of pulse repetition intervals between adjacent statistical intervals, and compare the mean difference with the decision threshold to merge adjacent statistical intervals that meet the conditions;

[0075] Step S3: Determine the maximum order of time difference based on the number of effective intervals and the pulse sequence length, and calculate the corresponding multi-order time difference sequence using the pulse arrival time;

[0076] Step S4: Calculate the typical value and occurrence number of the multi-order time difference sequence of pulse arrival time. Delete the typical value of the multi-order time difference sequence whose occurrence number is less than a preset threshold to obtain an effective pulse frame length vector.

[0077] Step S5: Perform differential operation on the effective pulse frame length vector, and obtain the pulse repetition interval modulation period of the non-cooperative radar radiation source by solving its greatest common divisor.

[0078] According to the method of the first aspect of the present invention, in step S1, the frequency and pulse width of the radar received data are statistically analyzed, pulses exceeding the conventional value and preset range are discarded, and the pulse repetition interval is calculated according to the pulse arrival time.

[0079] Δt k =t k+1 -t k ,1≤k≤K-1

[0080] Among them, t k Let K be the arrival time of the k-th pulse, and K be the total number of detected pulses.

[0081] Calculate the maximum value of the pulse repetition interval sequence. and minimum value And set the discretization interval Δt for the statistical interval of the pulse repetition interval sequence;

[0082] Statistical analysis is performed on each pulse repetition interval to construct a histogram of the pulse repetition interval sequence.

[0083] According to the method of the first aspect of the present invention, in step S2, the mean difference of the pulse repetition interval between adjacent statistical intervals is calculated:

[0084] Δx n =x n+1 -x n ,1≤n≤N′-1

[0085] Where, x n N represents the average pulse repetition interval within the nth statistical interval, and N′ represents the total number of statistical intervals.

[0086] Compare the mean difference with the decision threshold:

[0087] Δx n ≤0.7Δt

[0088] If Δx n If ≤0.7Δt holds, then the pulse repetition intervals of two adjacent statistical intervals are merged; otherwise, the mean difference of pulse repetition intervals in subsequent adjacent statistical intervals is calculated, and the judgment and merging operations are continuously performed until the analysis of all statistical intervals is completed. The final number of valid statistical intervals is recorded as N.

[0089] According to the method of the first aspect of the present invention, in step S3, the maximum order P of the time difference is determined based on the number N of effective intervals and the pulse sequence length:

[0090] P = min{100N, S⁻¹}

[0091] Where S represents the length of the pulse sequence after removing outliers;

[0092] Solve for pulse arrival time difference sequences of different orders:

[0093]

[0094] According to the method of the first aspect of the present invention, in step S4:

[0095] Histogram statistics were performed on the obtained multi-order pulse arrival time difference sequences to obtain the statistical characteristic parameters x = [x1, x2, ..., x...]. L ] and y = [y1, y2, ..., y L ], where L is the number of typical values, x l For the l-th typical value of the pulse time difference sequence, y l The number of occurrences of the l-th typical value;

[0096] Sort y in descending order, and starting from y2, determine whether the element should be kept. If the element is equal to or greater than 2 / 3 of the average of all preceding elements, keep the element and continue searching. If the element is less than 2 / 3 of the average of all preceding elements, stop searching and delete all elements after the element.

[0097] Synchronously delete the corresponding typical values ​​in x. The remaining typical values ​​in x are the effective pulse frame lengths, which are defined as a new vector. The number of elements is M.

[0098] According to the method of the first aspect of the present invention, in step S5, the vector is... Sort each element in ascending order to obtain the vector x′=[x′1,x′2,…,x…′]. M ] Calculate the difference in the effective frame length of the pulse:

[0099] Δx m =|x′ m+1 -x′ m |,m=1,2,…,M-1

[0100] Solve the sequence Δx m The greatest common divisor ΔT is used to obtain the pulse repetition interval modulation period of the non-cooperative radar radiation source.

[0101] Specific examples

[0102] like Figure 1 As shown, the method and system for estimating the modulation period of pulse repetition intervals of non-cooperative radar radiation sources include the following steps:

[0103] S1. Establish an initial histogram of the pulse repetition interval for non-cooperative radar radiation sources. First, perform statistical analysis on the frequency and pulse width of the radar reconnaissance data, and remove pulses that exceed the normal values ​​and preset ranges; second, calculate the pulse repetition interval according to the pulse arrival time:

[0104] Δt k =t k+1 -t k ,1≤k≤K-1

[0105] Among them, t k Let be the arrival time of the k-th pulse, and K be the total number of detected pulses. Calculate the maximum value of the pulse repetition interval sequence. and minimum value The discretization interval Δt of the statistical interval of the pulse repetition interval sequence is set. Finally, statistics are performed for each pulse repetition interval, and a histogram of the pulse repetition interval sequence is constructed.

[0106] S2. To address the dispersion effect of the discretized interval Δt on the pulse repetition interval sequence, it is necessary to merge the obtained pulse repetition interval statistical intervals. First, calculate the mean difference of the pulse repetition intervals between adjacent statistical intervals:

[0107] Δx n =x n+1 -x n ,1≤n≤N′-1

[0108] Where, x n Let N' represent the average pulse repetition interval within the nth statistical interval, and N′ represent the total number of statistical intervals. Next, determine the following conditions:

[0109] Δx n ≤0.7Δt

[0110] If the above formula holds true, the pulse repetition intervals of two adjacent statistical intervals are merged; otherwise, the mean difference of pulse repetition intervals in subsequent adjacent statistical intervals is calculated, and judgment and merging operations are performed until the analysis of all statistical intervals is completed. The final number of valid statistical intervals is recorded as N.

[0111] S3. Calculate the multi-order time difference sequence of pulse arrival times. First, determine the maximum order P of the time difference based on the number of effective intervals N and the pulse sequence length. The specific method is as follows:

[0112] P = min{100N, S⁻¹}

[0113] Where S represents the length of the pulse sequence after removing outliers. Next, the pulse arrival time difference sequences of different orders are solved using the following method:

[0114]

[0115] S4. Extract the effective pulse frame length. First, perform histogram statistics on the obtained multi-order pulse arrival time difference sequences to obtain the statistical characteristic parameters x = [x1, x2, ..., x...]. L ] and y = [y1, y2, ..., y L ], where L is the number of typical values, x lFor the l-th typical value of the pulse time difference sequence, y l Let y be the number of occurrences of the l-th typical value. Next, sort y in descending order, and starting from y2, determine whether an element should be retained. Specifically: if the element is equal to or greater than 2 / 3 of the average of all preceding elements, retain this element and continue searching; if the element is less than 2 / 3 of the average of all preceding elements, stop searching and delete all elements after this element. Finally, synchronously delete the corresponding typical values ​​in x. The remaining typical values ​​in x constitute the effective pulse frame length, which is defined as a new vector. The number of elements is M.

[0116] S5. Estimate the modulation period of the pulse repetition interval. First, convert the vector... Sort the elements in ascending order to obtain the vector x′=[x′1,x′2,…,x′]. M ] Calculate the difference in the effective frame length of the pulse:

[0117] Δx m =|x′ m+1 -x′ m |,m=1,2,…,M-1

[0118] Secondly, solve the sequence Δx m By finding the greatest common divisor ΔT, the pulse repetition interval modulation period of the non-cooperative radar radiation source can be obtained.

[0119] A second aspect of this invention provides a system for estimating the modulation period of a non-cooperative radar radiation source pulse repetition interval. The system includes:

[0120] The first processing unit is configured to: perform statistical analysis on the frequency and pulse width of the radar received data to remove abnormal pulses in the radar received data, and establish a histogram of the pulse repetition interval sequence.

[0121] The second processing unit is configured to: calculate the mean difference of pulse repetition intervals between adjacent statistical intervals, compare the mean difference with a decision threshold, and merge adjacent statistical intervals that meet the conditions;

[0122] The third processing unit is configured to: determine the maximum order of time difference based on the number of effective intervals and the pulse sequence length, and calculate the corresponding multi-order time difference sequence using the pulse arrival time;

[0123] The fourth processing unit is configured to: calculate the typical value and the number of occurrences of the multi-order time difference sequence of pulse arrival time, and delete the typical values ​​of the multi-order time difference sequence whose number of occurrences is less than a preset threshold, so as to obtain an effective pulse frame length vector.

[0124] The fifth processing unit is configured to perform differential operations on the effective pulse frame length vector and obtain the pulse repetition interval modulation period of the non-cooperative radar radiation source by solving its greatest common divisor.

[0125] According to the system of the second aspect of the present invention, the first processing unit is specifically configured to: perform statistical analysis on the frequency and pulse width of the radar received data, perform a rejection operation on pulses that exceed the normal value and preset range, and calculate the pulse repetition interval according to the pulse arrival time.

[0126] Δt k =t k+1 -t k ,1≤k≤K-1

[0127] Among them, t k Let K be the arrival time of the k-th pulse, and K be the total number of detected pulses.

[0128] Calculate the maximum value of the pulse repetition interval sequence. and minimum value And set the discretization interval Δt for the statistical interval of the pulse repetition interval sequence;

[0129] Statistical analysis is performed on each pulse repetition interval to construct a histogram of the pulse repetition interval sequence.

[0130] According to the system of the second aspect of the present invention, the second processing unit is specifically configured to: calculate the mean difference between the pulse repetition intervals of adjacent statistical intervals:

[0131] Δx n =x n+1 -x n ,1≤n≤N′-1

[0132] Where, x n N represents the average pulse repetition interval within the nth statistical interval, and N′ represents the total number of statistical intervals.

[0133] Compare the mean difference with the decision threshold:

[0134] Δx n ≤0.7Δt

[0135] If Δx n If ≤0.7Δt holds, then the pulse repetition intervals of two adjacent statistical intervals are merged; otherwise, the mean difference of pulse repetition intervals in subsequent adjacent statistical intervals is calculated, and the judgment and merging operations are continuously performed until the analysis of all statistical intervals is completed. The final number of valid statistical intervals is recorded as N.

[0136] According to the system of the second aspect of the present invention, the third processing unit is specifically configured to: determine the maximum order P of the time difference based on the number N of effective intervals and the pulse sequence length.

[0137] P = min{100N, S⁻¹}

[0138] Where S represents the length of the pulse sequence after removing outliers;

[0139] Solve for pulse arrival time difference sequences of different orders:

[0140]

[0141] According to the system of the second aspect of the present invention, the fourth processing unit is specifically configured to: perform histogram statistics on the obtained multi-order pulse arrival time difference sequence to obtain the statistical characteristic parameter x = [x1, x2, ..., x...] of the multi-order time difference sequence. L ] and y = [y1, y2, ..., y L ], where L is the number of typical values, x l For the l-th typical value of the pulse time difference sequence, y l The number of occurrences of the l-th typical value;

[0142] Sort y in descending order, and starting from y2, determine whether the element should be kept. If the element is equal to or greater than 2 / 3 of the average of all preceding elements, keep the element and continue searching. If the element is less than 2 / 3 of the average of all preceding elements, stop searching and delete all elements after the element.

[0143] Synchronously delete the corresponding typical values ​​in x. The remaining typical values ​​in x are the effective pulse frame lengths, which are defined as a new vector. The number of elements is M.

[0144] According to the system of the second aspect of the present invention, the fifth processing unit is specifically configured to: process vectors Sort the elements in ascending order to obtain the vector x′=[x′1,x′2,…,x′]. M ] Calculate the difference in the effective frame length of the pulse:

[0145] Δx m =|x′ m+1 -x′ m |,m=1,2,…,M-1

[0146] Solve the sequence Δx m The greatest common divisor ΔT is used to obtain the pulse repetition interval modulation period of the non-cooperative radar radiation source.

[0147] A third aspect of this invention discloses an electronic device. The electronic device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps in the method for estimating the modulation period of a non-cooperative radar radiation source pulse repetition interval as described in the first aspect of this disclosure.

[0148] Figure 2 This is a structural diagram of an electronic device according to an embodiment of the present invention, such as... Figure 2 As shown, the electronic device includes a processor, memory, communication interface, display screen, and input device connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, Near Field Communication (NFC), or other technologies. The display screen can be an LCD screen or an e-ink screen. The input device can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the device's casing, or an external keyboard, touchpad, or mouse.

[0149] Those skilled in the art will understand that Figure 2 The structure shown is merely a structural diagram of the part related to the technical solution of this disclosure and does not constitute a limitation on the electronic device to which the solution of this application is applied. The specific electronic device may include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements.

[0150] A fourth aspect of this invention discloses a computer-readable storage medium. The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps in the method for estimating the modulation period of a non-cooperative radar radiation source pulse repetition interval as described in the first aspect of this disclosure.

[0151] In summary, this invention addresses the technical challenge of poor accuracy in estimating the pulse repetition interval modulation period of non-cooperative radar sources under conditions of low signal-to-noise ratio and high pulse loss rate. First, it establishes an initial histogram of the pulse repetition interval for the non-cooperative radar source and merges adjacent statistical intervals whose mean difference is less than the discretization interval, thereby reducing the dispersion effect caused by the discretization interval. Then, it calculates the multi-order time difference sequence of pulse arrival times and extracts the effective pulse frame length. Finally, it estimates the pulse repetition interval modulation period of the non-cooperative radar source by solving for the greatest common divisor. This invention requires no prior information about the pulse repetition interval modulation type and can achieve rapid and accurate estimation of the pulse repetition interval modulation period of non-cooperative radar sources.

[0152] The estimation results of the pulse repetition interval modulation period of non-cooperative radar radiation sources provided by this invention can offer technical support for radar radiation source sorting. Using the estimated period provided by this invention for frame screening, multiple typical values ​​of pulse repetition intervals can be identified simultaneously. Therefore, the batch processing of radar radiation sources can be effectively reduced, improving the processing efficiency of radar reconnaissance data.

[0153] The estimation results of the pulse repetition interval modulation period of non-cooperative radar radiation sources in this invention can be used to reconstruct radar pulse sample sub-maps with high accuracy under conditions of low signal-to-noise ratio and high pulse loss rate. It can provide favorable support for the identification of pulse repetition interval modulation type of non-cooperative radar radiation sources, target type identification, and target operating mode identification.

[0154] Please note that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for estimating the modulation period of pulse repetition intervals of non-cooperative radar radiation sources, characterized in that, The method includes: Step S1: Perform statistical analysis on the frequency and pulse width of the radar received data to remove abnormal pulses in the radar received data and establish a histogram of the pulse repetition interval sequence. Step S2: Calculate the mean difference of pulse repetition intervals between adjacent statistical intervals, and compare the mean difference with the decision threshold to merge adjacent statistical intervals that meet the conditions; Step S3: Determine the maximum order of time difference based on the number of effective intervals and the pulse sequence length, and calculate the corresponding multi-order time difference sequence using the pulse arrival time; Step S4: Calculate the typical value and occurrence number of the multi-order time difference sequence of pulse arrival time. Delete the typical value of the multi-order time difference sequence whose occurrence number is less than a preset threshold to obtain an effective pulse frame length vector. Step S5: Perform differential operation on the effective pulse frame length vector, and obtain the pulse repetition interval modulation period of the non-cooperative radar radiation source by solving its greatest common divisor. In step S1: The frequency and pulse width of the radar received data are statistically analyzed. Pulses that exceed the normal value and preset range are discarded, and the pulse repetition interval is calculated according to the pulse arrival time. in, For the first The arrival time of each pulse The total number of detected pulses; Calculate the maximum value of the pulse repetition interval sequence. and minimum value And set the discretization interval of the statistical interval of the pulse repetition interval sequence. ; For each pulse repetition interval, statistics are performed to construct a histogram of the pulse repetition interval sequence; In step S2: Calculate the mean difference between pulse repetition intervals of adjacent statistical intervals: in, Indicates the first The average value of the pulse repetition interval within a statistical interval. Indicates the total number of the statistical intervals; Compare the mean difference with the decision threshold: if If the condition is met, the pulse repetition intervals of two adjacent statistical intervals are merged; otherwise, the mean difference of pulse repetition intervals in subsequent adjacent statistical intervals is calculated, and the judgment and merging operations are continuously performed until the analysis of all statistical intervals is completed. The final number of valid statistical intervals is recorded as follows. ; In step S3: Based on the number of valid intervals The pulse sequence length determines the maximum order of the time difference. : in, This indicates the length of the pulse sequence after removing outliers; Solve for pulse arrival time difference sequences of different orders: In step S4: Histogram statistics were performed on the obtained multi-order pulse arrival time difference sequences to obtain statistical characteristic parameters of the multi-order time difference sequences. and ,in, The number of typical values, The first pulse time difference sequence A typical value, For the first The number of typical values ​​that occur; right Sort in descending order and from First, determine whether the element should be kept. If the element is equal to or greater than 2 / 3 of the average of all previous elements, keep the element and continue searching. If the element is less than 2 / 3 of the average of all previous elements, stop searching and delete all elements after the element. Synchronous deletion The corresponding typical value, The remaining typical value is the effective pulse frame length, which is defined as a new vector. The number of elements is ; In step S5: vector Sort each element in ascending order to obtain a vector. Calculate the difference in the effective frame length of the pulse: Solving the sequence Greatest common divisor The pulse repetition interval modulation period of the non-cooperative radar radiation source is obtained.

2. A system for estimating the modulation period of a non-cooperative radar radiation source pulse repetition interval, characterized in that, The system includes: The first processing unit is configured to: perform statistical analysis on the frequency and pulse width of the radar received data to remove abnormal pulses in the radar received data, and establish a histogram of the pulse repetition interval sequence. The second processing unit is configured to: calculate the mean difference of pulse repetition intervals between adjacent statistical intervals, compare the mean difference with a decision threshold, and merge adjacent statistical intervals that meet the conditions; The third processing unit is configured to: determine the maximum order of time difference based on the number of effective intervals and the pulse sequence length, and calculate the corresponding multi-order time difference sequence using the pulse arrival time; The fourth processing unit is configured to: calculate the typical value and the number of occurrences of the multi-order time difference sequence of pulse arrival time, and delete the typical values ​​of the multi-order time difference sequence whose number of occurrences is less than a preset threshold, so as to obtain an effective pulse frame length vector. The fifth processing unit is configured to: perform differential operations on the effective pulse frame length vector and obtain the pulse repetition interval modulation period of the non-cooperative radar radiation source by solving its greatest common divisor; The first processing unit is specifically configured as follows: The frequency and pulse width of the radar received data are statistically analyzed. Pulses that exceed the normal value and preset range are discarded, and the pulse repetition interval is calculated according to the pulse arrival time. in, For the first The arrival time of each pulse The total number of detected pulses; Calculate the maximum value of the pulse repetition interval sequence. and minimum value And set the discretization interval of the statistical interval of the pulse repetition interval sequence. ; For each pulse repetition interval, statistics are performed to construct a histogram of the pulse repetition interval sequence; The second processing unit is specifically configured as follows: Calculate the mean difference between pulse repetition intervals of adjacent statistical intervals: in, Indicates the first The average value of the pulse repetition interval within a statistical interval. Indicates the total number of the statistical intervals; Compare the mean difference with the decision threshold: if If the condition is met, the pulse repetition intervals of two adjacent statistical intervals are merged; otherwise, the mean difference of pulse repetition intervals in subsequent adjacent statistical intervals is calculated, and the judgment and merging operations are continuously performed until the analysis of all statistical intervals is completed. The final number of valid statistical intervals is recorded as follows. ; The third processing unit is specifically configured as follows: Based on the number of valid intervals The pulse sequence length determines the maximum order of the time difference. : in, This indicates the length of the pulse sequence after removing outliers; Solve for pulse arrival time difference sequences of different orders: The fourth processing unit is specifically configured as follows: Histogram statistics were performed on the obtained multi-order pulse arrival time difference sequences to obtain statistical characteristic parameters of the multi-order time difference sequences. and ,in, The number of typical values, The first pulse time difference sequence A typical value, For the first The number of typical values ​​that occur; right Sort in descending order and from First, determine whether the element should be kept. If the element is equal to or greater than 2 / 3 of the average of all previous elements, keep the element and continue searching. If the element is less than 2 / 3 of the average of all previous elements, stop searching and delete all elements after the element. Synchronous deletion The corresponding typical value, The remaining typical value is the effective pulse frame length, which is defined as a new vector. The number of elements is ; The fifth processing unit is specifically configured as follows: vector Sort each element in ascending order to obtain a vector. Calculate the difference in the effective frame length of the pulse: Solving the sequence Greatest common divisor The pulse repetition interval modulation period of the non-cooperative radar radiation source is obtained.

3. An electronic device, characterized in that, The electronic device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps in the method for estimating the pulse repetition interval modulation period of a non-cooperative radar radiation source as described in claim 1.

4. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps in the method for estimating the pulse repetition interval modulation period of a non-cooperative radar radiation source as described in claim 1.

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