Target hiding method and device for synthetic aperture radar, equipment and medium

Abstract

The application discloses a target hiding method and device for a synthetic aperture radar, equipment and a medium, relates to the technical field of radars, and comprises the following steps: imaging a target to be hidden by using a transmitting signal of the synthetic aperture radar to obtain target parameters of the target to be hidden; phase modulating the transmitting signal of the synthetic aperture radar according to the target parameters to obtain a first signal; amplitude modulating the first signal to obtain a second signal; and hiding the target to be hidden by using the second signal. The application can hide important targets by transmitting only a low-power signal, is low in cost, is not easy to expose, and is high in safety.

Description

Technical Field

[0001] This application relates to the field of radar technology, and in particular to target concealment methods, apparatuses, devices, and media for synthetic aperture radar. Background Technology

[0002] Synthetic Aperture Radar (SAR) can detect targets. To prevent important targets from being detected by SAR, they need to be concealed. There are two main existing methods for target concealment: one is to use special materials to absorb the detection signal emitted by SAR, resulting in a weak echo returning to the SAR receiver, thus achieving a stealth effect; the other is to use a jammer to emit high-power jamming signals to cover and obscure important targets, thus masking the information in the SAR image. However, both methods have certain problems: the former requires coating the target surface with special materials, which is not only costly but also only effective against a single SAR system and prone to failure; the latter usually requires emitting high-power jamming signals, which is not only energy-intensive but also easily detected. Summary of the Invention

[0003] The main objective of this application is to propose a target concealment method, apparatus, device, and medium for synthetic aperture radar, so as to achieve low-power target concealment.

[0004] To achieve the above objectives, one aspect of this application proposes a target concealment method for synthetic aperture radar, the method comprising the following steps:

[0005] The target to be hidden is imaged using the transmitted signal of synthetic aperture radar in order to obtain the target parameters of the target to be hidden;

[0006] The transmitted signal of the synthetic aperture radar is phase-modulated according to the target parameters to obtain a first signal;

[0007] The first signal is amplitude modulated to obtain the second signal;

[0008] The target to be hidden is concealed using the second signal.

[0009] In some embodiments, the process of imaging the target to be hidden using the transmitted signal of synthetic aperture radar to obtain the target parameters of the target to be hidden includes the following steps:

[0010] The point target is imaged using the transmitted signal of the synthetic aperture radar to obtain the target parameters of the point target; wherein, the target parameters include scattering coefficient, range, and azimuth position; the target to be hidden includes the point target;

[0011] The transmitted signal of the synthetic aperture radar is:

[0012]

[0013] Where rect(·) is the rectangle function, T r t is the pulse width. r For fast time, f0 is the carrier frequency, K r To adjust the frequency;

[0014] The signal expression obtained by imaging the point target is:

[0015]

[0016] Where, σ n Let t be the scattering coefficient of the point target. a For slow time, B r R is the signal bandwidth. n0 Let c be the initial distance from the point target, and T be the speed of light. a For the time to synthesize the aperture, τ n For azimuth time delay, f dc f is the center of the Doppler frequency. a γ is the Doppler frequency, and γ is the Doppler modulation frequency.

[0017] In some embodiments, the step of phase-modulating the transmitted signal of the synthetic aperture radar according to the target parameters to obtain a first signal includes the following steps:

[0018] Based on the target parameters, the transmitted signal of the synthetic aperture radar is compared with... Perform convolution, and in the slow time dimension, with δ(t) a -τ n Convolution is performed to perform phase modulation, resulting in the first signal as follows:

[0019]

[0020] Among them, a a This is the azimuth beam pattern, where j is the imaginary unit and R... n This refers to the distance from the point target.

[0021] In some embodiments, the step of amplitude modulation of the first signal to obtain the second signal includes the following steps:

[0022] The first signal and σ n Multiplying by exp(jπ) to perform amplitude modulation, the second signal is obtained as follows:

[0023]

[0024] In some embodiments, hiding the target to be hidden using the second signal includes the following steps:

[0025] The second signal is transmitted, and the second signal is mixed with the echo signal of the target to be hidden in response to the transmitted signal, thereby hiding the target.

[0026] To achieve the above objectives, another aspect of the embodiments of this application proposes a target concealment device for synthetic aperture radar, the device comprising:

[0027] The target imaging unit is used to image the target to be hidden using the transmitted signal of the synthetic aperture radar in order to obtain the target parameters of the target to be hidden.

[0028] A phase modulation unit is used to perform phase modulation on the transmitted signal of the synthetic aperture radar according to the target parameters to obtain a first signal;

[0029] An amplitude modulation unit is used to modulate the amplitude of the first signal to obtain a second signal;

[0030] A target hiding unit is used to hide the target to be hidden using the second signal.

[0031] To achieve the above objectives, another aspect of this application provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the above-described method.

[0032] To achieve the above objectives, another aspect of the embodiments of this application proposes a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method.

[0033] The embodiments of this application include at least the following beneficial effects:

[0034] This application utilizes the transmitted signal of a synthetic aperture radar (SAR) to image a target to be hidden, thereby obtaining the target parameters of the target. Based on the target parameters, the transmitted signal of the SAR is phase-modulated to obtain a first signal; the first signal is then amplitude-modulated to obtain a second signal; and the second signal is used to hide the target. This application only requires the transmission of a low-power signal to achieve the concealment of important targets, which is not only low-cost but also difficult to detect, offering high security. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A flowchart illustrating a target concealment method for synthetic aperture radar provided in an embodiment of this application;

[0037] Figure 2 An example flowchart of a target concealment method for synthetic aperture radar provided in this application embodiment;

[0038] Figure 3 Example images of imaging results provided in this application but not processed by this application;

[0039] Figure 4 Example images of imaging results processed by this application are provided for embodiments of this application;

[0040] Figure 5 This is a schematic diagram of the target concealment device for synthetic aperture radar provided in an embodiment of this application;

[0041] Figure 6 This is a schematic diagram of the hardware structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0042] 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 of this application and are not intended to limit it. In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application; they are merely examples of apparatuses and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.

[0043] It is understood that the terms “first,” “second,” etc., used in this application may be used herein to describe various concepts, but unless otherwise stated, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the words “if,” “when,” or “in response to a determination” as used herein may be interpreted as “when…” or “when…” or “in response to a determination.”

[0044] As used in this application, the terms "at least one", "multiple", "each", "any", etc., "at least one" includes one, two or more, "multiple" includes two or more, "each" refers to each of the corresponding multiples, and "any" refers to any one of the multiples.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0046] Reference Figure 1 This application provides a target concealment method for synthetic aperture radar, which may include, but is not limited to, steps S100 to S130, as follows:

[0047] S100: Image the target to be hidden using the transmitted signal of synthetic aperture radar to obtain the target parameters of the target to be hidden;

[0048] S110: The transmitted signal of the synthetic aperture radar is phase-modulated according to the target parameters to obtain a first signal;

[0049] S120: Amplitude modulation is performed on the first signal to obtain the second signal;

[0050] S130: Hide the target to be hidden using the second signal.

[0051] Optionally, the step of imaging the target to be hidden using the transmitted signal of synthetic aperture radar to obtain the target parameters of the target to be hidden includes the following steps:

[0052] The point target is imaged using the transmitted signal of the synthetic aperture radar to obtain the target parameters of the point target; wherein, the target parameters include scattering coefficient, range, and azimuth position; the target to be hidden includes the point target;

[0053] The transmitted signal of the synthetic aperture radar is:

[0054]

[0055] Where rect(·) is the rectangle function, T r t is the pulse width. r For fast time, f0 is the carrier frequency, K r To adjust the frequency;

[0056] The signal expression obtained by imaging the point target is:

[0057]

[0058] Where, σ n Let t be the scattering coefficient of the point target. a For slow time, B r R is the signal bandwidth. n0 Let c be the initial distance from the point target, and T be the speed of light. a For the time to synthesize the aperture, τ n For azimuth time delay, f dc f is the center of the Doppler frequency. a γ is the Doppler frequency, and γ is the Doppler modulation frequency.

[0059] Optionally, the step of phase-modulating the transmitted signal of the synthetic aperture radar according to the target parameters to obtain a first signal includes the following steps:

[0060] Based on the target parameters, the transmitted signal of the synthetic aperture radar is compared with... Perform convolution, and in the slow time dimension, with δ(t) a -τ n Convolution is performed to perform phase modulation, resulting in the first signal as follows:

[0061]

[0062] Among them, a a This is the azimuth beam pattern, where j is the imaginary unit and R... n This refers to the distance from the point target.

[0063] Optionally, the step of amplitude modulation of the first signal to obtain the second signal includes the following steps:

[0064] The first signal and σ n Multiplying by exp(jπ) to perform amplitude modulation, the second signal is obtained as follows:

[0065]

[0066] Optionally, the step of using the second signal to hide the target includes the following steps:

[0067] The second signal is transmitted, and the second signal is mixed with the echo signal of the target to be hidden in response to the transmitted signal, thereby hiding the target.

[0068] The following section will provide a detailed introduction and explanation of the solutions in the embodiments of this application, using specific application examples.

[0069] Reference Figure 2, Figure 2 This is an example flowchart of a target concealment method for synthetic aperture radar provided in this embodiment.

[0070] Specifically, this embodiment includes the following steps:

[0071] Step 1: Image the key target and obtain its main parameters (including scattering coefficient σ, range, and azimuth).

[0072] If the SAR transmitted signal is:

[0073]

[0074] Where rect(·) is the rectangle function, T r t is the pulse width. r For fast time, f0 is the carrier frequency, K r To adjust the frequency.

[0075] Taking a point target as an example, imaging it yields the result shown in the following formula:

[0076]

[0077] Where, σ n Let t be the target scattering coefficient. a For slow time, B r R is the signal bandwidth. n0 Let c be the distance to the target, and T be the speed of light. a For the time to synthesize the aperture, τ n For azimuth time delay, f dc f is the center of the Doppler frequency. a γ is the Doppler frequency, and γ is the Doppler modulation frequency.

[0078] Step 2: Phase modulation of the SAR signal.

[0079] For SAR signals in the fast time dimension and Perform convolution, and in the slow time dimension, with δ(t) a -τ n By performing convolution, the signal obtained is:

[0080]

[0081] Step 3: Amplitude modulation is applied to the signal from Step 2.

[0082] Multiply the amplitude of the signal in step two by σ n If exp(jπ), then the signal becomes:

[0083]

[0084] Step 4: Transmit the signal from Step 3.

[0085] The signal from step three is transmitted via a transmitter and received by a SAR receiver, where it is mixed with the target echo. After radar imaging processing, the key target can be concealed.

[0086] The following describes a more specific implementation method.

[0087] Under the following radar parameters (bandwidth 300MHz, pulse width .01, modulation frequency 3×10¹⁵Hz / s, wavelength 0.03m, synthetic aperture length 1m, beamwidth 0.03rad, closest slant range 10km, velocity 150m / s, Doppler bandwidth 300Hz), imaging a "T"-shaped target yields the following results: Figure 3 The imaging results shown are illustrated, with the two dots at the lower left and lower right corners serving as reference targets. It can be seen that without the method of this embodiment, the "T"-shaped target can be well represented in the image by SAR. After processing using the method of this embodiment, the following results can be obtained: Figure 4 The results shown are from Figure 4 As can be seen, the "T" shape has been hidden, and only two reference dot targets remain in the SAR image. Therefore, after processing by the method in this embodiment, key targets can be well hidden without affecting other targets. This method not only has a good target hiding effect but also has minimal impact on other targets, exhibiting good concealment capabilities.

[0088] The beneficial effects of this embodiment include:

[0089] 1. This embodiment can achieve the concealment of key targets at low cost;

[0090] 2. This embodiment achieves the concealment of key targets while having minimal impact on other targets;

[0091] 3. The target of this embodiment is not easily detected by the SAR system and has good concealment.

[0092] Reference Figure 5 This application also provides a target concealment device for synthetic aperture radar (SAR), which can implement the above-described target concealment method for SAR. The device includes:

[0093] The target imaging unit is used to image the target to be hidden using the transmitted signal of the synthetic aperture radar in order to obtain the target parameters of the target to be hidden.

[0094] A phase modulation unit is used to perform phase modulation on the transmitted signal of the synthetic aperture radar according to the target parameters to obtain a first signal;

[0095] An amplitude modulation unit is used to modulate the amplitude of the first signal to obtain a second signal;

[0096] A target hiding unit is used to hide the target to be hidden using the second signal.

[0097] It is understood that the content of the above method embodiments is applicable to the present device embodiments. The specific functions implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0098] This application also provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the method of this application. This electronic device can be any smart terminal, including tablet computers, in-vehicle computers, etc.

[0099] It is understood that the content of the above method embodiments is applicable to the device embodiments. The specific functions implemented by the device embodiments are the same as those of the methods of this application, and the beneficial effects achieved are also the same as those achieved by the methods of this application.

[0100] Please see Figure 6 , Figure 6 The hardware structure of an electronic device according to another embodiment is illustrated. The electronic device includes:

[0101] The processor 601 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this application.

[0102] The memory 602 can be implemented as a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM). The memory 602 can store the operating system and other applications. When the technical solutions provided in the embodiments of this specification are implemented through software or firmware, the relevant program code is stored in the memory 602 and is called and executed by the processor 601.

[0103] The input / output interface 603 is used to implement information input and output;

[0104] The communication interface 604 is used to enable communication and interaction between this device and other devices. Communication can be achieved through wired means (such as USB, network cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.).

[0105] Bus 605 transmits information between various components of the device (e.g., processor 601, memory 602, input / output interface 603, and communication interface 604);

[0106] The processor 601, memory 602, input / output interface 603, and communication interface 604 are connected to each other within the device via bus 605.

[0107] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method of this application.

[0108] It is understood that the content of the above method embodiments is applicable to this storage medium embodiment. The specific functions implemented in this storage medium embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0109] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0110] The embodiments described in this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0111] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this application, and may include more or fewer steps than shown, or combine certain steps, or different steps.

[0112] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0113] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or appropriate combinations thereof.

[0114] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0115] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0116] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0117] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0118] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0119] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing programs, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0120] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A target concealment method for synthetic aperture radar, characterized in that, The method includes the following steps: The target to be hidden is imaged using the transmitted signal of synthetic aperture radar to obtain the target parameters of the target to be hidden; wherein, the target to be hidden includes a T-shaped target; The transmitted signal of the synthetic aperture radar is phase-modulated according to the target parameters to obtain a first signal; The first signal is amplitude modulated to obtain the second signal; The target to be hidden is concealed using the second signal; The process of imaging the target to be hidden using the transmitted signal of synthetic aperture radar to obtain the target parameters of the target includes the following steps: The point target is imaged using the transmitted signal of the synthetic aperture radar to obtain the target parameters of the point target; wherein, the target parameters include scattering coefficient, range, and azimuth position; the target to be hidden includes the point target; The transmitted signal of the synthetic aperture radar is: ； Where, rect For rectangle functions, The pulse width. To save time, For carrier frequency, To adjust the frequency; The signal expression obtained by imaging the point target is: ； in, The scattering coefficient of the point target. For slow time, For signal bandwidth, Let c be the initial distance from the point target, and c be the speed of light. For the time to synthesize the pore size, For azimuth time delay, , Center of Doppler frequency, For Doppler frequency, To tune the frequency for Doppler; The step of performing phase modulation on the transmitted signal of the synthetic aperture radar according to the target parameters to obtain a first signal includes the following steps: Based on the target parameters, the transmitted signal of the synthetic aperture radar is compared with... Perform convolution, and in the slow time dimension with Convolution is performed to perform phase modulation, resulting in the first signal as follows: ； in, This is the azimuth beam pattern. The imaginary unit, This refers to the distance from the point target.

2. The target concealment method for synthetic aperture radar according to claim 1, characterized in that, The step of amplitude modulation of the first signal to obtain the second signal includes the following steps: Connect the first signal with Multiplying them to perform amplitude modulation yields the second signal as follows: 。 3. The target concealment method for synthetic aperture radar according to any one of claims 1 to 2, characterized in that, The method of using the second signal to hide the target to be hidden includes the following steps: The second signal is transmitted, and the second signal is mixed with the echo signal of the target to be hidden in response to the transmitted signal, thereby hiding the target.

4. A target concealment device for synthetic aperture radar, characterized in that, The apparatus is used to implement the target concealment method for synthetic aperture radar as described in claim 1, the apparatus comprising: The target imaging unit is used to image the target to be hidden using the transmitted signal of the synthetic aperture radar in order to obtain the target parameters of the target to be hidden. A phase modulation unit is used to perform phase modulation on the transmitted signal of the synthetic aperture radar according to the target parameters to obtain a first signal; An amplitude modulation unit is used to modulate the amplitude of the first signal to obtain a second signal; A target hiding unit is used to hide the target to be hidden using the second signal.

5. An electronic device, characterized in that, The electronic device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the method as described in any one of claims 1 to 3.

6. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1 to 3.

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