Intermittent sampling forwarding interference resisting method for ground radar based on time domain pit finding

Abstract

The invention relates to a method and a system for a ground radar to confront intermittent sampling forwarding interference based on time domain pit finding, and the method comprises the steps: carrying out the module value solving of a sum path orthogonal baseband signal received by the ground radar, carrying out the averaging calculation according to a sliding window, obtaining a mean value sequence, and extracting a threshold level; performing over-threshold detection to obtain a threshold level matrix, calculating the interference number and the interference duty ratio of the threshold level matrix, and judging whether interference exists or not; calculating an interference zero-setting threshold according to the threshold level matrix; and comparing the mean value sequence of the sum path orthogonal baseband signal with an interference zero setting threshold to remove interference. According to time domain characteristics of intermittent sampling forwarding interference, a signal level value is calculated by using a time domain concave searching method, an interference transition zone is removed, the signal level value is ensured not to be influenced by interference to the greatest extent, and the interference zero-setting threshold is subjected to zero-setting processing through comparison and comprehensive logic judgment of the interference zero-setting threshold, so that the interference level value is accurately determined. And the confrontation to the intermittent sampling forwarding interference is realized.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the field of radar countermeasure technology, and in particular to a method, system and electronic device for ground radar to counter intermittent sampling and forwarding interference based on time domain notching. Background Art

[0002] Radar confrontation and counter-confrontation are important components of modern electronic warfare. With the continuous development of digital frequency storage and forwarding technology, the electromagnetic combat environment faced by ground radars is becoming increasingly complex. Digital frequency storage and forwarding interference has a strong coherence with the radar transmission signal and can cover the radar operating frequency. Intermittent sampling and forwarding interference, as a typical digital frequency storage and forwarding interference, has been widely used in jammers. It can solve the problem of isolation between the transmit and receive antennas of the jammer and achieve intra-pulse interference on the radar. After pulse compression, intermittent sampling and forwarding interference appears as multiple false target signals, which can suppress the real target signal, making it impossible for the ground radar to stably track the target and achieve the purpose of RF stealth.

[0003] The recognition time of digital frequency storage and forwarding interference on radar waveform has reached the microsecond level. Conventional methods of waveform agility or frequency agility can no longer counteract intermittent sampling and forwarding interference. Zhang Jianzhong, Mu Heqiang, Wen Shuliang and others proposed a method based on LFM segmented pulse compression to resist intermittent sampling and forwarding interference in their paper "Anti-intermittent sampling and forwarding interference method based on LFM segmented pulse compression" (Journal of Electronics and Information Technology, 2019, 41(7): 1712-1720.). This method uses the idea of ​​orthogonal and mutual cover of sub-pulses, uses segmented LFM signals as the pulse response signals of the matched filter, constructs a narrowband filter group, and uses the orthogonality between segmented LFM signals to effectively suppress intermittent interference. However, this method depends on the signal form, and the constructed narrowband filter group depends on the slice width of the intermittent sampling and forwarding interference. If the filter bandwidth is wide, the interference will affect the target detection effect; if the designed filter bandwidth is narrow, the anti-interference effect is good, but the number of filters in the filter group is large, the system design is complex, the signal processing calculation complexity is large, and the sidelobes after processing are high.

[0004] Judging from publicly available information, existing methods for countering intermittent sampling and forwarding interference have problems such as reliance on radar transmission waveforms and complex system design, making them difficult to apply and transplant in a systematic manner.

[0005] Therefore, it is necessary to improve one or more problems existing in the above-mentioned related technical solutions.

[0006] It should be noted that this section is intended to provide background or context for the technical solutions of the present disclosure stated in the claims. The description herein is not admitted to be prior art by virtue of being included in this section. Summary of the invention

[0007] The purpose of the embodiments of the present disclosure is to provide a method and system for a ground radar to combat intermittent sampling and forwarding interference based on time domain notching, thereby overcoming one or more problems caused by limitations and defects of related technologies at least to a certain extent.

[0008] The embodiment of the present disclosure first provides a method for ground radar to counteract intermittent sampling and forwarding interference based on time domain notching, including:

[0009] S101, performing modulus processing on the sum-path orthogonal baseband signals received by the ground radar, and then performing mean calculation on the processed modulus values ​​to obtain a mean sequence, and extracting a threshold level from the mean sequence;

[0010] S102, performing a threshold detection on the sum-path orthogonal baseband signal according to the threshold level to obtain a threshold level matrix, and calculating the number of interferences and the interference duty cycle of the threshold level matrix to determine whether the sum-path orthogonal baseband signal has interference;

[0011] S103, determining the width of the interference area according to the threshold level matrix, and calculating the interference zeroing threshold according to the width;

[0012] S104, comparing the mean sequence of the summed orthogonal baseband signals with the interference zeroing threshold to remove interference.

[0013] In one embodiment of the present disclosure, the process of S101 is as follows:

[0014] The sum of the orthogonal baseband signals in one coherent processing cycle of the ground radar is represented by a matrix as shown below:

[0015]

[0016] Where, T CPI is the coherent processing cycle, N is the number of pulses in a coherent processing cycle, A ij represents the amplitude of the sum-path orthogonal baseband signal of the jth distance unit in the i-th pulse repetition period within the coherent processing period, the value range of i is [1, N], and the value range of j is [1, M]; T r is the pulse repetition period, T bm is the gate width, F s is the sampling frequency, then the length of the orthogonal baseband signal M = F s T bm ;

[0017] The above matrix is ​​processed by modulus value to obtain the following formula:

[0018]

[0019] For the i-th pulse signal A of the orthogonal baseband signal ij Perform sliding window processing with a window length of win_len and a step of step_len points. The number of sliding windows is P. The modulus values ​​of the sum of the orthogonal baseband signals in the window are averaged, covering the i-th pulse signal. The average sequence obtained is avg i =[avg i1 ,avg i2 ,…,avg iM ], extract the mean sequence avg i The maximum value avg imax As a threshold level gate i1 .

[0020] In one embodiment of the present disclosure, the process of S102 includes:

[0021] Performing a threshold detection on the sum-path orthogonal baseband signal according to the threshold level to obtain a threshold level matrix;

[0022] The interference width is set according to the interference pattern, and the positions and numbers of the areas with continuous zero values ​​and a width greater than the interference width in the threshold level matrix are recorded to obtain a matrix of areas not exceeding the threshold;

[0023] The interference number and interference duty ratio of the threshold level matrix are calculated according to the non-threshold area matrix to determine whether the sum-path orthogonal baseband signal has interference.

[0024] In one embodiment of the present disclosure, in S102, the threshold level matrix B in It is expressed as follows:

[0025]

[0026] Matrix C of the area not exceeding the threshold i It is expressed as follows:

[0027]

[0028] Wherein, dis_numberP represents the number of the Pth continuous non-threshold area, that is, the width of the interference area, dis_startP represents the starting point of the Pth continuous non-threshold area, and dis_endP represents the end point of the Pth continuous non-threshold area.

[0029] In one embodiment of the present disclosure, if dis_number ≥ 1, the jam duty ratio jam_percent is performed. i The calculation formula is as follows:

[0030]

[0031] In the formula, sum(B in ) represents the number of interfering signals that meet the threshold.

[0032] In an embodiment of the present disclosure, if jam_percent i ≤0.8, it is determined that interference exists; otherwise, it is determined that no interference exists.

[0033] In an embodiment of the present disclosure, the process of S103 includes:

[0034] If dis_number in C i >4, extract the fourth unthresholded region of A i , that is, the amplitude corresponding to dis_start4 - dis_end4 in C i , and remove the average value gate of 5 points before and after both sides of the region. i2 As the interference cancellation threshold;

[0035] If 1 < dis_number ≤ 4 in C i , extract the last thresholded region and calculate the average value gate i2 As the interference cancellation threshold;

[0036] If dis_number = 1 in C i , and it is determined that this region is the front-end region of the echo signal, then calculate the average value gate of the front-end region of the echo signal i2 , if this region is the back-end region of the echo signal, then calculate the average value gate of the back-end region of the echo signal i2 As the interference cancellation threshold.

[0037] In an embodiment of the present disclosure, the process of S104 includes:

[0038] Compare the amplitude of the i-th pulse signal A ij of the sum-channel quadrature baseband signal with the interference cancellation threshold, and the result is as follows:

[0039]

[0040] In the formula, K represents the threshold coefficient. Perform the above comparison process on all pulse signals, and set the pulse signal data greater than K×gate i2 to zero to remove interference.

[0041] The embodiments of the present disclosure further provide a system for ground radar countermeasure against intermittent sampling and repeater jamming based on time-domain concave search. The system includes:

[0042] The threshold level acquisition module is used to perform modulus processing on the orthogonal baseband signal received by the ground radar, and then perform mean value calculation on the processed modulus to obtain a mean value sequence, and extract the threshold level from the mean value sequence;

[0043] An interference determination module is used to perform a threshold detection on the sum-path orthogonal baseband signal according to the threshold level to obtain a threshold level matrix, and calculate the number of interferences and the interference duty cycle of the threshold level matrix to determine whether the sum-path orthogonal baseband signal has interference;

[0044] An interference zeroing threshold calculation module, used to determine the width of the interference area according to the threshold level matrix, and calculate the interference zeroing threshold according to the width;

[0045] The interference removal module is used to compare the mean sequence of the summed orthogonal baseband signals with the interference zeroing threshold to remove interference.

[0046] The present disclosure also provides an electronic device, including:

[0047] Processor; and

[0048] A memory, configured to store executable instructions of the processor;

[0049] The processor is configured to execute the steps of any one of the above-mentioned methods for ground radar counteracting intermittent sampling forwarding interference based on time domain notching by executing the executable instructions.

[0050] The technical solution provided by the embodiments of the present disclosure may have the following beneficial effects:

[0051] A method and system for counteracting intermittent sampling forwarding interference by a ground radar based on time domain concave search in the disclosed embodiment, according to the time domain characteristics of intermittent sampling forwarding interference, the signal level value is calculated by using the time domain concave search method, and the interference transition band introduced by the transient effect of the filter is removed, so as to maximize the signal level value from being affected by interference, and through comparison and comprehensive logical judgment of the interference zeroing threshold, each pulse signal in a coherent processing cycle is zeroed according to the obtained interference zeroing threshold, so as to achieve countermeasures against intermittent sampling forwarding interference. The present invention has a strong adaptability to intermittent sampling forwarding interference, and can achieve better countermeasure effects when the interference pulse period and duty cycle vary in a relatively large range. The present invention has been implemented on a ground radar and verified by air confrontation with an actual jammer. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The drawings herein are incorporated into the specification and constitute a part of the specification, represent embodiments consistent with the present disclosure, and are used together with the specification to explain the principles of the present disclosure. Obviously, the drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0053] Figure 1 A schematic flow chart showing a method for counteracting intermittent sampling forwarding interference by a ground radar based on time domain notching in an exemplary embodiment of the present disclosure;

[0054] Figure 2 A graph showing the real part of an echo signal within a range period when intermittent interference exists in an exemplary embodiment of the present disclosure;

[0055] Figure 3 A result diagram of a pulse modulus value before and after the "time domain concave search" process is shown in an exemplary embodiment of the present disclosure;

[0056] Figure 4 A comparison diagram of the results before and after the "time domain concave search" process in an exemplary embodiment of the present disclosure is shown;

[0057] Figure 5 A schematic structural diagram of an electronic device in an exemplary embodiment of the present disclosure is shown;

[0058] Figure 6 A schematic diagram of the structure of a program product for implementing a method for ground radar to combat intermittent sampling forwarding interference based on time-domain notching in an exemplary embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0059] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the disclosure will be more comprehensive and complete and to fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0060] In addition, the accompanying drawings are only schematic illustrations of the embodiments of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and their repeated descriptions will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0061] First of all, it should be noted that the purpose of the present invention is to provide a generally applicable method for resisting intermittent sampling and forwarding interference. For the convenience of description, the method for resisting intermittent sampling and forwarding interference of the present invention is named as a "time domain notch search" processing method.

[0062] In this example implementation, a method for ground radar to counteract intermittent sampling and forwarding interference based on time domain notching is first provided. Please refer to Figure 1 , may include: Step S101-Step S104. Specifically as follows:

[0063] S101, performing modulus processing on the orthogonal baseband signal received by the ground radar, then performing mean calculation on the modulus obtained by the processing to obtain a mean sequence, and extracting a threshold level from the mean sequence. When performing mean calculation on the modulus, mean calculation can be performed according to sliding window processing to obtain a mean sequence.

[0064] S102, performing a threshold detection on the summed orthogonal baseband signals according to the threshold level to obtain a threshold level matrix, and calculating the number of interferences and the interference duty cycle of the threshold level matrix to determine whether the summed orthogonal baseband signals have interference.

[0065] S103, determining the width of the interference area according to the threshold level matrix, and calculating the interference zeroing threshold according to the width.

[0066] S104, comparing the mean sequence of the summed orthogonal baseband signals with the interference zeroing threshold to remove interference.

[0067] In this embodiment, according to the time domain characteristics of intermittent sampling forwarding interference, the signal level value is calculated by using the time domain concave search method, and the interference transition band introduced by the transient effect of the filter is removed, so as to maximize the signal level value and ensure that it is not affected by interference. By comparing the interference zeroing threshold and making a comprehensive logical judgment, each pulse signal in a coherent processing cycle is zeroed according to the obtained interference zeroing threshold, so as to achieve the confrontation with the intermittent sampling forwarding interference. The present invention has a strong adaptability to the intermittent sampling forwarding interference, and can achieve a good confrontation effect when the interference pulse period and duty cycle have a relatively large range of variation. The present invention has been implemented on a ground radar and verified by air confrontation with a real jammer.

[0068] The specific implementation process of the above steps is described in detail below.

[0069] In one embodiment, the process of S101 is as follows:

[0070] The sum of the orthogonal baseband signals in one coherent processing cycle of the ground radar is represented by a matrix as shown below:

[0071]

[0072] Where, T CPIis the coherent processing cycle, N is the number of pulses in a coherent processing cycle, A ij represents the amplitude of the sum-path orthogonal baseband signal of the jth distance unit in the i-th pulse repetition period within the coherent processing period, the value range of i is [I, Nl, the value range of j is [1, M]; T r is the pulse repetition period, T bm is the gate width, F s is the sampling frequency, then the length of the orthogonal baseband signal M = F s T bm ;

[0073] The above matrix is ​​processed by modulus value to obtain the following formula:

[0074]

[0075] For the i-th pulse signal A of the orthogonal baseband signal ij Perform sliding window processing with a window length of win_len and a step of step_len points. The number of sliding windows is P. The modulus values ​​of the sum of the orthogonal baseband signals in the window are averaged, covering the i-th pulse signal. The average sequence obtained is avg i =[avg i1 ,avg i2 ,…,avg iM ], extract the mean sequence avg i The maximum value avg imax As a threshold level gate i1 .

[0076] In this embodiment, the summed orthogonal baseband signals are subjected to modulus processing, and the maximum value in the mean value sequence is used as the threshold level to provide a threshold level value for subsequent interference removal.

[0077] In one embodiment, the process of S102 includes:

[0078] Performing a threshold detection on the sum-path orthogonal baseband signal according to the threshold level to obtain a threshold level matrix;

[0079] The interference width is set according to the interference pattern, and the positions and numbers of the areas with continuous zero values ​​and a width greater than the interference width in the threshold level matrix are recorded to obtain a matrix of areas not exceeding the threshold;

[0080] The interference number and interference duty ratio of the threshold level matrix are calculated according to the non-threshold area matrix to determine whether the sum-path orthogonal baseband signal has interference.

[0081] Among them, the threshold level matrix B in It is expressed as follows:

[0082]

[0083] Unthresholded region matrix C i is expressed as follows:

[0084]

[0085] In the formula, dis_numberP represents the number of the Pth consecutive unthresholded region, that is, the width of the interference region, dis_startP represents the starting point of the Pth consecutive unthresholded region, and dis_endP represents the ending point of the Pth consecutive unthresholded region.

[0086] If dis_number ≥ 1, then the interference duty cycle jam_percent i is calculated, and the calculation formula is as follows:

[0087]

[0088] In the formula, sum(B in ) represents the number of interference that meets the threshold.

[0089] If jam_percent i ≤ 0.8, it is determined that there is interference, otherwise it is determined that there is no interference.

[0090] In one embodiment, the process of S103 includes:

[0091] If in C i dis_number > 4, then extract the fourth unthresholded region of A i , that is, the amplitude corresponding to dis_start4 - dis_end4 in C i , and remove 5 points before and after both sides of the region to find the average value gate i2 as the interference zeroing threshold;

[0092] If in C i 1 < dis_number ≤ 4, then extract the last threshold region to find the average value gate i2 as the interference zeroing threshold;

[0093] If in C i dis_number = 1 and it is determined that this region is the front-end region of the echo signal, then take the average value gate i2 of the front-end region of the echo signal. If this region is the back-end region of the echo signal, then take the average value gate i2 of the back-end region of the echo signal as the interference zeroing threshold.

[0094] In one embodiment, the process of S104 includes:

[0095] For the i-th pulse signal A of the orthogonal baseband signal ij The amplitude of is compared with the interference zeroing threshold, and the result is as follows:

[0096]

[0097] Where K represents the threshold coefficient. All pulse signals are compared and processed as above. i2 The pulse signal data is reset to zero to remove interference.

[0098] The present invention is further described below in conjunction with implementation examples.

[0099] Assume that the coherent processing period of a pulse radar is 10ms and the pulse repetition period T r The number of transmitted pulses in a coherent processing cycle is 10, the pulse width is 128μs, the gate width is 165μs, and the sampling frequency F s =20MHz. Then the length of the baseband signal sampling points in one pulse repetition period is 3300 points, and the length used to calculate the signal level is 2560 points.

[0100] (1) Calculation of radar echo signal level

[0101] For the i-th pulse A of the received signal i Perform sliding window processing with a window length of win_len and a step of step_len points. The number of sliding windows is P. The modulus value of the signal in the window is averaged, covering the i-th pulse signal. The average sequence obtained is avg i =[avg i1 ,avg i2 ,…,avg iM ] Then the mean sequence avg i Find the maximum value avg imax Processing, recorded as threshold level gate i1 .

[0102] (2) Determining whether interference exists

[0103] According to the calculated gate i1 , for A i After threshold processing, the threshold level matrix B is obtained. i Perform continuous 0 judgment, and use the number of interferences and the interference duty cycle to determine whether there is interference.

[0104] (3) Interference Threshold Calculation

[0105] Select A according to the number of interference areas iThe corresponding baseband data modulus value is averaged and recorded as gate i2 .

[0106] (4) Interference elimination processing

[0107] A i The amplitude of each sampling point in is compared with the threshold of interference zeroing, and the following processing is performed:

[0108]

[0109] Each pulse is processed in steps 1 to 4 in turn. When intermittent sampling and forwarding interference countermeasures are completed, all sampling data in the corresponding i-th distance period are set to zero, otherwise no processing is performed.

[0110] Figure 2 The real part of the orthogonal baseband signal of a target tracking position under intermittent sampling and forwarding interference is shown in the figure before and after the time domain concave search processing. Figure 3 After the whole wave position is processed by time domain concave search, pulse compression and moving target detection, the time domain distance dimension profile of the target is as follows: Figure 4 As shown. Figure 2-4 It can be seen that when interference nulling is not performed, the target signal is submerged in the intermittent sampling forwarding interference and cannot be detected. After applying the interference nulling based on time domain notching of the present invention, the interference is effectively suppressed and the target signal can be detected normally.

[0111] The embodiment of the present application also provides a system for ground radar to counteract intermittent sampling and forwarding interference based on time domain notching, the system comprising:

[0112] The threshold level acquisition module is used to perform modulus processing on the orthogonal baseband signal received by the ground radar, and then perform mean value calculation on the processed modulus to obtain a mean value sequence, and extract the threshold level from the mean value sequence;

[0113] An interference determination module is used to perform a threshold detection on the sum-path orthogonal baseband signal according to the threshold level to obtain a threshold level matrix, and calculate the number of interferences and the interference duty cycle of the threshold level matrix to determine whether the sum-path orthogonal baseband signal has interference;

[0114] An interference zeroing threshold calculation module, used to determine the width of the interference area according to the threshold level matrix, and calculate the interference zeroing threshold according to the width;

[0115] The interference removal module is used to compare the mean sequence of the summed orthogonal baseband signals with the interference zeroing threshold to remove interference.

[0116] The working principle and operation process of the system in this embodiment are the same as those described in the above embodiments, and will not be described again here.

[0117] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0118] It should be noted that although several modules of the system for action execution are mentioned in the above detailed description, this division is not mandatory. In fact, according to an embodiment of the present invention, the features and functions of two or more modules described above can be concretized in one module. Conversely, the features and functions of a module described above can be further divided into multiple modules for concretization. The components displayed as modules may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of the present invention. Those of ordinary skill in the art can understand and implement it without paying creative work.

[0119] See also Figure 5 The embodiment of the present invention further provides an electronic device 300, which includes at least one memory 310, at least one processor 320, and a bus 330 for connecting different platform systems.

[0120] The memory 310 may include a readable medium in the form of a volatile memory, such as a random access memory (RAM) 311 and / or a cache memory 312 , and may further include a read-only memory (ROM) 313 .

[0121] Among them, the memory 310 also stores a computer program, and the computer program can be executed by the processor 320, so that the processor 320 executes the steps of the method for a ground radar based on time domain concave search to combat intermittent sampling forwarding interference in any embodiment of the present invention. The specific implementation method is consistent with the implementation method and the technical effect recorded in the above-mentioned embodiment of the method for a ground radar based on time domain concave search to combat intermittent sampling forwarding interference, and some contents will not be repeated here.

[0122] The memory 310 may also include a utility 314 having at least one program module 315, such program module 315 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0123] Accordingly, the processor 320 may execute the above-mentioned computer program, and may execute the utility 314 .

[0124] Bus 330 may represent one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processor or a local bus using any of a variety of bus architectures.

[0125] The electronic device 300 may also communicate with one or more external devices 340 such as keyboards, pointing devices, Bluetooth devices, etc., and may also communicate with one or more devices that can interact with the electronic device 300, and / or communicate with any device (such as a router, a modem, etc.) that enables the electronic device 300 to communicate with one or more other computing devices. Such communication may be performed through an input / output interface 350. In addition, the electronic device 300 may also communicate with one or more networks (such as a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) through a network adapter 360. The network adapter 360 may communicate with other modules of the electronic device 300 through a bus 330. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 300, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms.

[0126] An embodiment of the present invention also provides a computer-readable storage medium, which is used to store a computer program. When the computer program is executed, it implements the steps of the method for a ground radar based on time domain concave search to combat intermittent sampling and forwarding interference in the embodiment of the present invention. The specific implementation method is consistent with the implementation method and the technical effect recorded in the above-mentioned embodiment of the method for a ground radar based on time domain concave search to combat intermittent sampling and forwarding interference, and some contents will not be repeated here.

[0127] Figure 6The program product 400 provided in this embodiment for implementing the above-mentioned method of ground radar counteracting intermittent sampling forwarding interference based on time domain concave search is shown. It can adopt a portable compact disk read-only memory (CD-ROM) and include program code, and can be run on a terminal device, such as a personal computer. However, the program product 400 of the present invention is not limited to this. In the present invention, the readable storage medium can be any tangible medium containing or storing a program, which can be used by an instruction execution system, device or device or used in combination with it. The program product 400 can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared or semiconductor system, device or device, or any combination of the above. More specific examples of readable storage media (non-exhaustive list) include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0128] Computer-readable storage media may include data signals propagated in baseband or as part of a carrier wave, wherein readable program codes are carried. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The readable storage medium may also be any readable medium, which may send, propagate, or transmit a program for use by an instruction execution system, an apparatus, or a device or for use in combination with it. The program code contained on the readable storage medium may be transmitted by any suitable medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination of the above. The program code for performing the operation of the present invention may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, etc., and also conventional procedural programming languages ​​such as C language or similar programming languages. The program code may be executed entirely on a user computing device, partially on a user device, as an independent software package, partially on a user computing device, partially on a remote computing device, or entirely on a remote computing device or server. Where a remote computing device is involved, the remote computing device may be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., through the Internet using an Internet service provider).

[0129] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A method for ground radar to counteract intermittent sampling and forwarding interference based on time domain notching, characterized in that: include: S101, performing modulus processing on the sum-path orthogonal baseband signals received by the ground radar, and then performing mean calculation on the processed modulus values ​​to obtain a mean sequence, and extracting a threshold level from the mean sequence; S102, performing a threshold detection on the sum-path orthogonal baseband signal according to the threshold level to obtain a threshold level matrix, and calculating the number of interferences and the interference duty cycle of the threshold level matrix to determine whether the sum-path orthogonal baseband signal has interference; S103, determining the width of the interference area according to the threshold level matrix, and calculating the interference zeroing threshold according to the width; S104, comparing the mean sequence of the summed orthogonal baseband signals with the interference zeroing threshold to remove interference.

2. According to the method of claim 1, the method for ground radar to counteract intermittent sampling and forwarding interference based on time domain notching is characterized in that: The process of S101 is as follows: The sum of the orthogonal baseband signals in one coherent processing cycle of the ground radar is represented by a matrix as shown below: Where, T CPI is the coherent processing cycle, N is the number of pulses in a coherent processing cycle, A ij represents the amplitude of the sum-path orthogonal baseband signal of the j-th distance unit in the i-th pulse repetition period within the coherent processing period, the value range of i is [1, N], and the value range of j is [1, M]; T r is the pulse repetition period, T bm is the gate width, F s is the sampling frequency, then the length of the orthogonal baseband signal M = F s T bm ; The above matrix is ​​processed by modulus value to obtain the following formula: For the i-th pulse signal A of the orthogonal baseband signal ij Perform sliding window processing with a window length of win_len and a step of step_len points. The number of sliding windows is P. The modulus values ​​of the sum of the orthogonal baseband signals in the window are averaged, covering the i-th pulse signal. The average sequence obtained is avg i =[avg i1 ,avg i2 ,…,avg iM ], extract the mean sequence avg i The maximum value avg imax As a threshold level gate i1 .

3. The method for counteracting intermittent sampling and forwarding interference of ground radar based on time domain notching according to claim 2 is characterized in that: The S102 process includes: Performing a threshold detection on the sum-path orthogonal baseband signal according to the threshold level to obtain a threshold level matrix; The interference width is set according to the interference pattern, and the positions and numbers of the areas with continuous zero values ​​and a width greater than the interference width in the threshold level matrix are recorded to obtain a matrix of areas not exceeding the threshold; The interference number and interference duty ratio of the threshold level matrix are calculated according to the non-threshold area matrix to determine whether the sum-path orthogonal baseband signal has interference.

4. The method for ground radar to counteract intermittent sampling and forwarding interference based on time domain notching according to claim 3 is characterized in that: In S102, the threshold level matrix B in It is expressed as follows: Matrix C of the area not exceeding the threshold i It is expressed as follows: Wherein, dis_numberP represents the number of the Pth continuous non-threshold area, that is, the width of the interference area, dis_startP represents the starting point of the Pth continuous non-threshold area, and dis_endP represents the end point of the Pth continuous non-threshold area.

5. The method for ground radar to counteract intermittent sampling and forwarding interference based on time domain notching according to claim 4 is characterized in that: If dis_number ≥ 1, jam duty ratio jam_percent is used i The calculation formula is as follows: In the formula, sum(B in ) represents the number of interferences that meet the threshold.

6. The method for ground radar to counteract intermittent sampling and forwarding interference based on time domain notching according to claim 5 is characterized in that: If jam_percent i If ≤0.8, it is determined that interference exists, otherwise it is determined that there is no interference.

7. The method for ground radar to counteract intermittent sampling and forwarding interference based on time domain notching according to claim 6 is characterized in that: The S103 process includes: If C i If dis_number>4, extract A i The fourth non-threshold area, C i The amplitude corresponding to dis_start4-dis_end4 in the above figure is obtained by removing the 5 points before and after the two sides of the area to calculate the average gate. i2 As interference nulling threshold; If C i where 1 < dis_number ≤ 4, then extract the last threshold region and calculate the average value gate i2 as the interference cancellation threshold; If C i If dis_number=1, the area is judged to be the front end area of ​​the echo signal, and the front end area of ​​the echo signal is taken to calculate the average gate i2 If the area is the back end area of ​​the echo signal, then the back end area of ​​the echo signal is taken to calculate the average gate i2 As the interference nulling threshold.

8. The method for ground radar to counteract intermittent sampling and forwarding interference based on time domain notching according to claim 7 is characterized in that: The S104 process includes: For the i-th pulse signal A of the orthogonal baseband signal ij The amplitude of is compared with the interference zeroing threshold, and the result is as follows: Where K represents the threshold coefficient. All pulse signals are subjected to the above comparison process. i2 The pulse signal data is reset to zero to remove interference.

9. A system for ground radar to counteract intermittent sampling and forwarding interference based on time domain notching, characterized in that: The system comprises: The threshold level acquisition module is used to perform modulus processing on the orthogonal baseband signal received by the ground radar, and then perform mean value calculation on the processed modulus to obtain a mean value sequence, and extract the threshold level from the mean value sequence; An interference determination module is used to perform a threshold detection on the sum-path orthogonal baseband signal according to the threshold level to obtain a threshold level matrix, and calculate the number of interferences and the interference duty cycle of the threshold level matrix to determine whether the sum-path orthogonal baseband signal has interference; An interference zeroing threshold calculation module, used to determine the width of the interference area according to the threshold level matrix, and calculate the interference zeroing threshold according to the width; The interference removal module is used to compare the mean sequence of the summed orthogonal baseband signals with the interference zeroing threshold to remove interference.

Images