Ship discrimination method based on bistatic radar target combination correlation test

Abstract

The application relates to a ship identification method based on a bistatic radar target combination correlation test. The method comprises the following steps: obtaining a slow-time complex envelope sequence of a target by preprocessing echo signals obtained by simultaneously observing a same field of view region by bistatic radars; calculating a correlation coefficient of the target in the observation signals of two radars according to the first slow-time complex envelope sequence and the second slow-time complex envelope sequence; estimating a detection threshold value; and judging the type of the target in the field of view region based on the correlation coefficient and the detection threshold value, outputting position information of the ship target if the target is judged as the ship target, and eliminating the target as interference information if the target is judged as another target. The method can distinguish the ship target from other types of targets by using the bistatic radars, so that the identification purpose is achieved.

Description

Technical Field

[0001] This application relates to the field of radar target recognition technology, and in particular to a ship identification method based on the correlation test of dual-station radar target combination. Background Technology

[0002] In recent years, due to the rapid development of corner reflector technology, traditional identification methods have become insufficient to accurately identify ship targets.

[0003] Currently, methods for identifying ships and corner reflectors can be broadly categorized into two main types: feature extraction-based and deep learning-based. The former utilizes differences between ships and corner reflectors in radar cross section (RCS) scattering characteristics, high-range resolution profile (HRRP), motion characteristics, and polarization characteristics for identification; the latter uses hierarchical feature extraction structures to characterize the raw data, such as using Support Vector Machines (SVM) and Extreme Learning Machines (ELM) for identification.

[0004] Current methods for identifying ships and corner reflectors primarily rely on monostation radar architectures. Compared to monostation radar, multistation radar offers systemic advantages such as active countermeasures, coordinated control, diverse measures, and combined spatiotemporal frequency information domain effects. Therefore, multistation radar technology has been widely applied and developed in recent years to combat active jamming. However, in the area of ​​combating passive jamming, corresponding methods for identifying corner reflectors and ships based on multistation radar still lack a suitable approach. Summary of the Invention

[0005] Therefore, it is necessary to provide a ship identification method based on bistatic radar target combination correlation test that can accurately identify ship targets and passive interference, in order to address the above-mentioned technical problems.

[0006] A ship identification method based on bistatic radar target combination correlation test, the method comprising:

[0007] Acquire a first echo signal and a second echo signal, wherein the first echo signal and the second echo signal are obtained by observation of the same field of view by the corresponding radars in the bistatic radar;

[0008] After preprocessing the first echo signal and the second echo signal respectively, the first slow-time complex envelope sequence and the second slow-time complex envelope sequence of the target in the field of view region are obtained.

[0009] Based on the first slow-time complex envelope sequence and the second slow-time complex envelope sequence, the correlation coefficient of the target is calculated, and the detection threshold is estimated.

[0010] Based on the correlation coefficient and detection threshold, the target in the field of view is classified. If it is determined to be a ship target, the position information of the ship target is output. If it is determined to be other targets, they are removed as interference information.

[0011] In one embodiment, the field of view includes at least two targets to be identified.

[0012] In one embodiment, the two targets to be identified in the field of view are a ship target and a corner reflector.

[0013] In one embodiment, when there are multiple targets to be identified in the field of view, the first slow-time complex envelope sequence and the second slow-time complex envelope sequence each include slow-time complex envelope sequences corresponding to multiple targets. The bistatic radar is associated to form multiple target combinations. For two targets to be identified in each target combination, the correlation coefficient between the two targets to be identified and the corresponding detection threshold value are calculated using the corresponding first slow-time complex envelope sequence and the second slow-time complex envelope sequence.

[0014] In one embodiment, the correlation coefficient between two targets to be identified in each target combination is calculated using the following formula, based on the corresponding first slow-time complex envelope sequence and second slow-time complex envelope sequence:

[0015]

[0016] In the above formula, ρ pp′ Let represent the correlation coefficient between the p-th target of one bistatic radar and the p′-th target of the other radar, and Re(·) denote the operation of taking the real part. H The conjugate transpose operation is represented by ||·||, and the vector 2-norm calculation is represented by ||·||. These are the first slow-time complex envelope sequence and the second slow-time complex envelope sequence, respectively.

[0017] The detection threshold is estimated based on the calculated correlation coefficient using the following formula:

[0018]

[0019] In the above formula, ξ pp′ ρ represents the detection threshold for the p-th target on one bistatic radar and the p′-th target on the other radar. 12|S , ρ 12|CThese represent the correlation coefficients when a ship target is present in the target combination and when the target combination consists entirely of corner reflectors, respectively. These represent the signal-to-noise ratios (SNRs) when the p-th target is a corner reflector on one bistatic radar and when the p′-th target is a corner reflector on the other radar.

[0020] In one embodiment, classifying the target in the field of view based on the correlation coefficient and the detection threshold includes:

[0021] In each target combination, if the calculated correlation coefficient is greater than the relevant detection threshold, then the target to be identified in that target combination is the same target, and it is a corner reflector.

[0022] If the calculated correlation coefficient is less than the relevant detection threshold, then one of the targets to be identified in the target combination is a ship target and the other is a corner reflector, or the targets to be identified are the same target, which is a ship target.

[0023] In one embodiment, after judging each group of target combinations, targets judged as corner reflectors are eliminated, and the remaining targets to be identified are ship targets.

[0024] This application also provides a ship identification device based on bistatic radar target combination correlation testing, the device comprising:

[0025] The target echo signal acquisition module is used to acquire a first echo signal and a second echo signal, wherein the first echo signal and the second echo signal are obtained by the corresponding radars in the bistatic radar observing the same field of view area respectively;

[0026] The slow-time complex envelope sequence extraction module is used to preprocess the first echo signal and the second echo signal respectively to obtain the first slow-time complex envelope sequence and the second slow-time complex envelope sequence of the target in the field of view.

[0027] The correlation coefficient and detection threshold calculation module is used to calculate the correlation coefficient of the target and estimate the detection threshold based on the first slow time complex envelope sequence and the second slow time complex envelope sequence.

[0028] The ship target recognition module is used to classify targets in the field of view based on the correlation coefficient and detection threshold. If the target is identified as a ship target, the module outputs the position information of the ship target. If the target is identified as another target, it is removed as interference information.

[0029] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program performing the following steps:

[0030] Acquire a first echo signal and a second echo signal, wherein the first echo signal and the second echo signal are obtained by observation of the same field of view by the corresponding radars in the bistatic radar;

[0031] After preprocessing the first echo signal and the second echo signal respectively, the first slow-time complex envelope sequence and the second slow-time complex envelope sequence of the target in the field of view region are obtained.

[0032] Based on the first slow-time complex envelope sequence and the second slow-time complex envelope sequence, the correlation coefficient of the target is calculated, and the detection threshold is estimated.

[0033] Based on the correlation coefficient and detection threshold, the target in the field of view is classified. If it is determined to be a ship target, the position information of the ship target is output. If it is determined to be other targets, they are removed as interference information.

[0034] A computer-readable storage medium having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0035] Acquire a first echo signal and a second echo signal, wherein the first echo signal and the second echo signal are obtained by observation of the same field of view by the corresponding radars in the bistatic radar;

[0036] After preprocessing the first echo signal and the second echo signal respectively, the first slow-time complex envelope sequence and the second slow-time complex envelope sequence of the target in the field of view region are obtained.

[0037] Based on the first slow-time complex envelope sequence and the second slow-time complex envelope sequence, the correlation coefficient of the target is calculated, and the detection threshold is estimated.

[0038] Based on the correlation coefficient and detection threshold, the target in the field of view is classified. If it is determined to be a ship target, the position information of the ship target is output. If it is determined to be other targets, they are removed as interference information.

[0039] The aforementioned ship identification method based on bistatic radar target combination correlation testing preprocesses the echo signals obtained from simultaneous observations of the same field of view by bistatic radar to obtain a slow-time complex envelope sequence of the target. Based on the first and second slow-time complex envelope sequences, the correlation coefficients of the target in the observation signals of the two radars are calculated, and a detection threshold is estimated. Then, based on the correlation coefficients and the detection threshold, the target in the field of view is classified. If it is identified as a ship target, its position information is output; otherwise, it is discarded as interference. This method utilizes bistatic radar to distinguish ship targets from other types of targets, thus achieving the purpose of identification. Attached Figure Description

[0040] Figure 1 This is an application environment diagram of a ship identification method based on bistatic radar target combination correlation test in one embodiment;

[0041] Figure 2 This is a schematic diagram of the anisotropic and isotropic distribution of RCS in one embodiment, wherein, Figure 2 (a) is a schematic diagram of the RCS fluctuation distribution of the ship. Figure 2 (b) is a schematic diagram of the RCS fluctuation distribution of the corner reflector;

[0042] Figure 3 This is a flowchart illustrating the entire ship identification method in one embodiment;

[0043] Figure 4 This is a structural block diagram of a ship identification device based on bistatic radar target combination correlation test in one embodiment.

[0044] Figure 5 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0046] Existing technologies for identifying ship targets and other types of targets all employ monostation radar, which suffers from computational complexity and implementation difficulties. Figure 1 As shown, a ship identification method based on the correlation test of dual-station radar target combinations is provided, including the following steps:

[0047] Step S100: Acquire the first echo signal and the second echo signal, wherein the first echo signal and the second echo signal are obtained by the corresponding radars in the bistatic radar observing the same field of view area.

[0048] Step S110: After preprocessing the first echo signal and the second echo signal respectively, the first slow-time complex envelope sequence and the second slow-time complex envelope sequence of the target in the field of view are obtained.

[0049] Step S120: Calculate the correlation coefficient of the target and estimate the detection threshold based on the first slow-time complex envelope sequence and the second slow-time complex envelope sequence.

[0050] Step S130: Based on the correlation coefficient and detection threshold, classify the target in the field of view. If it is determined to be a ship target, output the position information of the ship target. If it is determined to be other targets, remove them as interference information.

[0051] In this embodiment, a bistatic radar inter-pulse ship target identification method based on signal fusion is provided, utilizing the differences in spatial scattering characteristics between ship targets and other target categories. First, the initial data acquired by the bistatic radar is preprocessed to extract the target's complex envelope sequence. Then, the correlation coefficient of the bistatic radar target combination is calculated, and the detection threshold is estimated. Finally, a correlation test is performed to determine the target type and output the target position parameters.

[0052] In this embodiment, the target to be identified in the observed field of view can be a ship or a corner reflector.

[0053] In this embodiment, the application scenarios for which the method described herein is applicable include situations where there are at least two targets to be identified in the field of view, namely a ship target and a corner reflector. When there are multiple targets to be identified in the field of view, there may be multiple ship targets and multiple corner reflectors.

[0054] When there are multiple targets to be identified in the field of view, there will be multiple sets of target combinations after correlation by the bistatic radar. That is, when there are N targets to be identified in the field of view, there will be N times N sets of target combinations. Thus, the two targets in each set of target combinations may be the same target or different targets.

[0055] When detecting targets using radar, the echo data from ship targets is similar to that from corner reflectors. This makes the corner reflectors a passive source of interference, hindering the detection results. The following section will use this scenario as an example to illustrate the method presented in this paper.

[0056] Specifically, in this method, we consider two radars that are separately positioned and simultaneously transmit signals to receive echoes and detect targets. At this time, several corner reflectors (in this paper, we take the case where there is a ship target and a corner reflector in the field of view at the same time) are released as passive interference to protect the ship.

[0057] Let r1(t,q) and r2(t,q) represent the signals received by the two radars (radar 1 and radar 2) in a bistatic radar system, respectively, where t is the fast time domain and q is the slow time domain. Let 0 ≤ t ≤ T, where T is the Pulse Repetition Interval (PRI), and q = 1, 2, ..., Q, where Q is the number of PRIs. The received signal is a superposition of the target echo, the angular back echo, and noise, and can be expressed as:

[0058]

[0059] In formula (1), s(t,q) is the echo of the ship target, j(t,q) is the echo of the corner reflector target, and n(t,q) is clutter and noise.

[0060] Taking radar 1 as an example, let r s1k Let be the distance between radar 1 and the k-th target. Then s1(t,q) can be expressed as:

[0061]

[0062] In formula (2), s1(t) is the transmitted signal of radar 1, c is the speed of light, and λ is the signal wavelength. To receive the complex amplitude of the k-th target in the echo. Assume the ship target is a rapidly fluctuating target, satisfying the Swerling II fluctuation model. Therefore, A complex variable follows a Gaussian distribution. Furthermore, they are independently and identically distributed across different PRIs.

[0063] Let r j1k Let j1(t,q) be the distance between radar 1 and the m-th corner reflector. Then j1(t,q) can be expressed as:

[0064]

[0065] In formula (3), The complex amplitude of the m-th corner reflector in the received echo.

[0066] Because of the fixed geometry of corner reflectors, their echo characteristics typically do not change over time, thus they are considered stable targets. Therefore, it can be concluded that, in the absence of sudden changes in radar angle, It is a stable value that depends only on distance.

[0067] Therefore, there is a correlation difference between the complex amplitudes of ship signals and corner reflectors. For example... Figure 2 As shown, the radar cross section (RCS) of a real ship target is anisotropic, while the RCS of a corner reflector is isotropic. This patent identifies targets based on this difference in spatial scattering characteristics. Considering that after pulse compression, each PRI generates only one effective sample of the target's complex amplitude in each radar, and a single sample is insufficient to describe its correlation, this patent estimates its correlation by using multiple samples from several consecutive PRIs in the slow time domain.

[0068] In both radars, for the range cell corresponding to the detected target, the complex amplitudes within that range cell across multiple consecutive PRI intervals will form the target's slow-time complex envelope sequence (SCES). Taking radar 1 as an example, the slow-time complex envelope sequence of the p-th target from radar 1 can be expressed as:

[0069]

[0070] In formula (4), W 1 This is a complex envelope sequence of clutter and noise. Considering that clutter can be filtered out using various filtering methods, the remaining noise will be a Gaussian white noise sequence, i.e. I Q×Q It is a Q×Q dimensional unit matrix. Let V be the white noise variance of radar 1. The term represents a slow-time complex amplitude sequence (SCAS) that contains only the target signal. Essentially, it is a slow-time complex envelope sequence that does not contain noise or clutter.

[0071] If the p-th target is a ship... It can be written as:

[0072]

[0073] If the p-th target is the angular reflection... It can be written as:

[0074]

[0075] For the ship (the p-th target on radar 1), and The distribution can be represented as:

[0076]

[0077]

[0078] As mentioned earlier, due to the anisotropy of ship RCS scattering, the complex amplitude of ship targets from radar 1 and radar 2... They are mutually independent and can be represented as:

[0079]

[0080] Therefore, the SCASs of ship targets from the two radars are orthogonal to each other, and can be denoted as:

[0081]

[0082] In the formula (·) H This is the conjugate transpose. Similarly, since the Gaussian white noise from different radars is also independent, the SCEAs from the two radars are also orthogonal, and can be written as:

[0083]

[0084] For the corner reflectors (the p-th target of radar 1 and the p′-th target of radar 2), as mentioned above, the complex amplitudes from the corner reflectors of radar 1 and radar 2... It is a relatively stable value, therefore the corner reflectors from both radars Linear correlation. Let the mean powers of the angle reflection signals in radar 1 and radar 2 be respectively... Right now:

[0085]

[0086] From the above, we can conclude that:

[0087]

[0088] In formula (13), k is a coefficient related to the distance to the corresponding radar target, and:

[0089]

[0090] Unlike SCASs, SCESs from two radars are not linearly correlated due to the presence of noise, but they are still correlated and cross-correlated, which can be expressed as:

[0091]

[0092] In formula (14), Q is the number of PRI.

[0093] Due to the difference in RCS correlation between the two radars and the ship's corner reflector, targets can be identified by calculating the correlation coefficient and performing correlation detection. For a given target, the correlation coefficient between Radar 1 (the p-th target) and Radar 2 (the p′-th target) is calculated as follows:

[0094]

[0095] Assuming the implemented angle jamming type is dilution jamming, meaning the angled target and the ship target are distinguishable in terms of radar detection range and angle, after the two radars extract the inter-pulse SCES of one target in their respective range dimension and form a target combination, there are three possible scenarios for this target combination: both are ships; both are angled targets; one target is a ship and the other is an angled target. The correlation coefficients for each scenario will be analyzed below.

[0096] When all targets in the target combination are ships, as mentioned earlier, the SCASs of the ship targets are uncorrelated between the two radars, therefore we can conclude that:

[0097]

[0098] When one target in the target combination is a ship target and the other is a corner reflector, the SCASs of the ship target and the corner reflector are uncorrelated between the two radars, therefore we can conclude that:

[0099] ρ 12|S,C =0 (17)

[0100] When all targets in a target combination are corner reflectors, the SCASs of the same corner reflector are correlated between the two radars, which can be denoted as:

[0101]

[0102] In formula (18), Radar 1 and Radar 2 respectively Signal-to-noise ratio.

[0103] Therefore, based on the aforementioned differences in correlation coefficients, a discrimination algorithm can be designed to identify ship targets and corner reflectors through correlation tests.

[0104] In step S100, after the bistatic radar (including radar 1 and radar 2) observes the same field of view area simultaneously, they obtain the first echo signal (i.e. radar 1 echo signal) and the second echo signal (i.e. radar 2 echo signal) respectively. At this time, there are at least two targets in the field of view area, one of which is a ship target, i.e., a real target, and the other is a corner reflector, i.e., a false target.

[0105] In step S110, the first echo signal and the second echo signal are sequentially processed by echo pulse compression, coherent accumulation, MTI filtering of clutter, and then IFFT (inverse fast Fourier transform) to obtain the corresponding inter-pulse slow-time complex envelope sequences, namely the first slow-time complex envelope sequence (i.e., the slow-time complex envelope sequence of a target in radar 1) and the second slow-time complex envelope sequence (i.e., the slow-time complex envelope sequence of a target in radar 2).

[0106] In this embodiment, when there are multiple targets to be identified in the field of view, the first slow-time complex envelope sequence and the second slow-time complex envelope sequence each include the slow-time complex envelope sequences corresponding to the multiple targets. The bistatic radar is correlated to form multiple target combinations. For the two targets to be identified in each target combination, the correlation coefficient between the two targets to be identified and the corresponding detection threshold value are calculated using the corresponding first slow-time complex envelope sequence and the second slow-time complex envelope sequence.

[0107] Specifically, since there are multiple targets to be identified in the field of view (taking two as an example), corresponding slow-time complex envelope sequences will be extracted for different targets. Furthermore, due to the correlation between the two targets through bistatic radar, four target combinations will be obtained, including combinations where both targets are ships, combinations where both targets are corner reflectors, and combinations where one target is a ship and one corner reflector. In reality, since the number of targets in the field of view is deterministic, the combination of targets that are all corner reflectors can be identified as corner reflector targets. After removing these, the remaining targets are ship targets.

[0108] Specifically, for each target combination containing two targets to be identified, the correlation coefficient between the two targets is calculated using the corresponding first slow-time complex envelope sequence and second slow-time complex envelope sequence using the following formula:

[0109]

[0110] In formula (19), ρ pp′ Let represent the correlation coefficient between the p-th target of one bistatic radar and the p′-th target of the other radar, and Re(·) denote the operation of taking the real part. H The conjugate transpose operation is represented by ||·||, and the vector 2-norm calculation is represented by ||·||. These are the first slow-time complex envelope sequence and the second slow-time complex envelope sequence, respectively.

[0111] As mentioned earlier, the target combination formed by the correlation between the two radars is the correlation coefficient ρ of the ship in both cases. 12|S And the correlation coefficient ρ between one target being a ship and another target being angular reflection. 12|S,CUnder ideal conditions, both values ​​are 0. Therefore, the two cases mentioned above can be combined into one category, namely, the case involving ships. The corresponding correlation coefficient is uniformly expressed as ρ. 12|S At this point, the verification decision is actually a binary classification problem that determines whether all target combinations are angular reflections and whether there is a ship in the target combination. Therefore, the threshold can be chosen as:

[0112] The detection threshold is estimated based on the calculated correlation coefficient using the following formula:

[0113]

[0114] In formula (20), ξ pp′ ρ represents the detection threshold for the p-th target on one bistatic radar and the p′-th target on the other radar. 12|S , ρ 12|C These represent the correlation coefficients when a ship target is present in the target combination and when the target combination consists entirely of corner reflectors, respectively. These represent the signal-to-noise ratios (SNRs) when the p-th target is a corner reflector on one bistatic radar and when the p′-th target is a corner reflector on the other radar.

[0115] Specifically, the signal-to-noise ratio can be estimated from the complex envelope sequence, and the corresponding formula is:

[0116]

[0117] In formula (21), Representing slow-time complex envelope sequences respectively The signal power, Q represents the sequence length, i.e., the number of pulse accumulations, σ1 2 , σ2 2 These represent the noise power corresponding to radar 1 and radar 2, respectively.

[0118] In this embodiment, classifying targets in the field of view based on correlation coefficients and detection thresholds includes: in each target combination, if the calculated correlation coefficient is greater than the relevant detection threshold, the targets to be identified in that target combination are the same target, and are corner reflectors. If the calculated correlation coefficient is less than the relevant detection threshold, one target to be identified in that target combination is a ship target and the other is a corner reflector, or the targets to be identified are the same target, and are ship targets.

[0119] Furthermore, after judging each group of target combinations, targets judged as corner reflectors are eliminated, and the remaining targets to be identified are ship targets.

[0120] In one embodiment, the overall process of the ship identification method can also be as follows: Figure 3 As shown.

[0121] Among the ship identification methods based on the correlation test of dual-station radar target combinations, a ship identification method based on signal-level fusion based on inter-pulse and angle reflection of dual-station radar is proposed. Within one coherent processing cycle, the correlation coefficient of the multi-pulse complex envelope sequences of the two radar targets is calculated and a correlation test is performed. Field measurement data verifies the effectiveness of the algorithm. Compared with other identification methods, this method, based on the configuration of two radars, only requires calculating the correlation coefficient by extracting the slow-time complex envelope sequence of the target pulses to achieve identification. It has low system hardware requirements and advantages such as simple and direct algorithm, fast response, good real-time performance, and high identification success rate.

[0122] It should be understood that, although Figure 1 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 1 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0123] In one embodiment, such as Figure 4 As shown, a ship identification device based on bistatic radar target combination correlation test is provided, including: a target echo signal acquisition module 200, a slow-time complex envelope sequence extraction module 210, a correlation coefficient and detection threshold calculation module 220, and a ship target identification module 230, wherein:

[0124] The target echo signal acquisition module 200 is used to acquire a first echo signal and a second echo signal, wherein the first echo signal and the second echo signal are obtained by the corresponding radars in the bistatic radar observing the same field of view area respectively;

[0125] The slow-time complex envelope sequence extraction module 210 is used to preprocess the first echo signal and the second echo signal respectively to obtain the first slow-time complex envelope sequence and the second slow-time complex envelope sequence of the target in the field of view.

[0126] The correlation coefficient and detection threshold calculation module 220 is used to calculate the correlation coefficient of the target and estimate the detection threshold based on the first slow time complex envelope sequence and the second slow time complex envelope sequence.

[0127] The ship target recognition module 230 is used to classify targets in the field of view based on the correlation coefficient and detection threshold. If the target is identified as a ship target, the module outputs the position information of the ship target. If the target is identified as another target, the module removes it as interference information.

[0128] Specific limitations regarding the ship identification device based on bistatic radar target combination correlation testing can be found in the limitations of the ship identification method based on bistatic radar target combination correlation testing mentioned above, and will not be repeated here. Each module in the aforementioned ship identification device based on bistatic radar target combination correlation testing can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0129] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 5 As shown, the computer device includes a processor, memory, network interface, display screen, and input devices 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 network interface is used for communication with external terminals via a network connection. When executed by the processor, the computer program implements a ship identification method based on bistatic radar target combination correlation testing. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0130] Those skilled in the art will understand that Figure 5 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0131] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the following steps:

[0132] Acquire a first echo signal and a second echo signal, wherein the first echo signal and the second echo signal are obtained by observation of the same field of view by the corresponding radars in the bistatic radar;

[0133] After preprocessing the first echo signal and the second echo signal respectively, the first slow-time complex envelope sequence and the second slow-time complex envelope sequence of the target in the field of view region are obtained.

[0134] Based on the first slow-time complex envelope sequence and the second slow-time complex envelope sequence, the correlation coefficient of the target is calculated, and the detection threshold is estimated.

[0135] Based on the correlation coefficient and detection threshold, the target in the field of view is classified. If it is determined to be a ship target, the position information of the ship target is output. If it is determined to be other targets, they are removed as interference information.

[0136] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0137] Acquire a first echo signal and a second echo signal, wherein the first echo signal and the second echo signal are obtained by observation of the same field of view by the corresponding radars in the bistatic radar;

[0138] After preprocessing the first echo signal and the second echo signal respectively, the first slow-time complex envelope sequence and the second slow-time complex envelope sequence of the target in the field of view region are obtained.

[0139] Based on the first slow-time complex envelope sequence and the second slow-time complex envelope sequence, the correlation coefficient of the target is calculated, and the detection threshold is estimated.

[0140] Based on the correlation coefficient and detection threshold, the target in the field of view is classified. If it is determined to be a ship target, the position information of the ship target is output. If it is determined to be other targets, they are removed as interference information.

[0141] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0142] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0143] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements 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 ship identification method based on bistatic radar target combination correlation test, characterized in that, The method includes: Acquire a first echo signal and a second echo signal, wherein the first echo signal and the second echo signal are obtained by observing the same field of view area by corresponding radars in the bistatic radar, and the field of view area includes at least two targets to be identified, wherein the two targets to be identified are a ship target and a corner reflector, respectively. After preprocessing the first echo signal and the second echo signal respectively, the first slow-time complex envelope sequence and the second slow-time complex envelope sequence of the target in the field of view region are obtained. Based on the first slow-time complex envelope sequence and the second slow-time complex envelope sequence, the correlation coefficient of the target is calculated, and the detection threshold is estimated. Based on the correlation coefficient and detection threshold, the target in the field of view is classified. If it is determined to be a ship target, the position information of the ship target is output. If it is determined to be other targets, they are removed as interference information. When there are multiple targets to be identified in the field of view, the first slow time complex envelope sequence and the second slow time complex envelope sequence each include slow time complex envelope sequences corresponding to multiple targets. The bistatic radar is associated to form multiple target combinations. For the two targets to be identified in each target combination, the correlation coefficient between the two targets to be identified and the corresponding detection threshold value are calculated using the corresponding first slow time complex envelope sequence and the second slow time complex envelope sequence. For each target combination, the correlation coefficient between the two targets to be identified is calculated using the corresponding first slow-time complex envelope sequence and second slow-time complex envelope sequence, using the following formula: In the above formula, In a bistatic radar system, the first radar of the two radars is... The target and the first radar of another radar The correlation coefficient of each objective This indicates the operation of taking the real part. This indicates the conjugate transpose operation. This represents the calculation of the vector 2 norm. , These are the first slow-time complex envelope sequence and the second slow-time complex envelope sequence, respectively. The detection threshold is estimated based on the calculated correlation coefficient using the following formula: In the above formula, In a bistatic radar system, the first radar of the two radars is... The target and the first radar of another radar The detection threshold for each target. , These represent the correlation coefficients when a ship target is present in the target combination, and when the target combination consists entirely of corner reflectors, respectively. , These represent the first and second radars in a bistatic radar system. The target was a corner reflector and the first radar. The corresponding signal-to-noise ratio when the target is a corner reflector.

2. The ship identification method based on bistatic radar target combination correlation test according to claim 1, characterized in that, The step of classifying targets in the field of view based on the correlation coefficient and detection threshold includes: In each target combination, if the calculated correlation coefficient is greater than the relevant detection threshold, then the target to be identified in that target combination is the same target, and it is a corner reflector. If the calculated correlation coefficient is less than the relevant detection threshold, then one of the targets to be identified in the target combination is a ship target and the other is a corner reflector, or the targets to be identified are the same target, which is a ship target.

3. The ship identification method based on bistatic radar target combination correlation test according to claim 2, characterized in that, After judging each group of targets, targets identified as corner reflectors are eliminated, and the remaining targets to be identified are ship targets.

4. A ship identification device based on bistatic radar target combination correlation testing, characterized in that, The device implements the ship identification method based on bistatic radar target combination correlation test as described in any one of claims 1-3, including: The target echo signal acquisition module is used to acquire a first echo signal and a second echo signal, wherein the first echo signal and the second echo signal are obtained by the corresponding radars in the bistatic radar observing the same field of view area respectively; The slow-time complex envelope sequence extraction module is used to preprocess the first echo signal and the second echo signal respectively to obtain the first slow-time complex envelope sequence and the second slow-time complex envelope sequence of the target in the field of view. The correlation coefficient and detection threshold calculation module is used to calculate the correlation coefficient of the target and estimate the detection threshold based on the first slow time complex envelope sequence and the second slow time complex envelope sequence. The ship target recognition module is used to classify targets in the field of view based on the correlation coefficient and detection threshold. If the target is identified as a ship target, the module outputs the position information of the ship target. If the target is identified as another target, it is removed as interference information.

5. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 3.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 3.

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