Anti-deception jamming imaging method, device and equipment of synthetic aperture radar

Abstract

The invention provides an anti-deception jamming imaging method, device and equipment for a synthetic aperture radar, which can be applied to the technical field of radars. The method comprises the following steps: in response to an anti-deception jamming imaging request of a synthetic aperture radar, obtaining the number of non-uniform pulse interval periods; a pulse interval period sequence is determined according to the value range of the non-uniform pulse interval periods and the number of the non-uniform pulse interval periods, and the value range of the pulse interval periods is determined according to the fact that the blind area position of the synthetic aperture radar is not in the imaging area; azimuth reconstruction is carried out on the echo signals, reconstructed signals with uniform sampling intervals are obtained, and the echo signals represent signals with non-uniform azimuth sampling intervals of the synthetic aperture radar after emission signals sent by the synthetic aperture radar based on the pulse interval periodic sequence encounter a target; performing interference suppression on the reconstructed signal to obtain a target reconstructed signal; and carrying out azimuth reconstruction on the target reconstruction signal to obtain an image corresponding to the emission signal.

Description

Technical Field

[0001] The present disclosure relates to the field of radar technology, and in particular to an anti-deception interference imaging method, device and equipment for synthetic aperture radar. Background Art

[0002] As the electromagnetic environment becomes increasingly complex, synthetic aperture radar imaging systems will be interfered with by electromagnetic radiation caused intentionally or unintentionally by other electronic devices, especially active jammers based on digital radio frequency memory (DRFM) technology, which can intercept, store, modulate and forward radar signals in the airspace, produce very realistic false targets in the synthetic aperture radar (SAR) imaging results, form deceptive interference, and seriously affect the accuracy of synthetic aperture radar imaging results.

[0003] In the process of implementing the present disclosure, the inventors found that the related art mainly used an anti-spoofing interference method through a variable pulse repetition interval (PRI) strategy, but did not consider the suppression of residual interference under the condition of a variable pulse repetition interval, resulting in poor imaging quality. Summary of the invention

[0004] In view of the above problems, the present disclosure provides a method, apparatus, device, medium and program product for anti-deception interference imaging of synthetic aperture radar.

[0005] According to a first aspect of the present disclosure, a method for anti-deception interference imaging of a synthetic aperture radar is provided, comprising: obtaining the number of non-uniform pulse interval periods in response to a request for anti-deception interference imaging of the synthetic aperture radar; determining a pulse interval period sequence according to a value range of the non-uniform pulse interval period and the number of non-uniform pulse interval periods, wherein the value range of the non-uniform pulse interval period is determined according to the fact that the blind spot position of the synthetic aperture radar is not within the imaging area; reconstructing an echo signal in azimuth to obtain a reconstructed signal with uniform sampling interval, wherein the echo signal represents a signal with non-uniform azimuth sampling interval when a transmission signal sent by the synthetic aperture radar based on the pulse interval period sequence encounters a target and is reflected back to the synthetic aperture radar; performing interference suppression on the reconstructed signal to obtain a target reconstructed signal; and reconstructing the target reconstructed signal in azimuth to obtain an image corresponding to the transmission signal.

[0006] A second aspect of the present disclosure provides an anti-deception interference imaging device of a synthetic aperture radar, comprising: an acquisition module, a determination module, a first obtaining module, a second obtaining module and a third obtaining module.

[0007] The acquisition module is used to obtain the number of non-uniform pulse interval periods in response to an anti-deception interference imaging request of a synthetic aperture radar.

[0008] The determination module is used to determine the pulse interval period sequence according to the value range of the non-uniform pulse interval period and the number of the non-uniform pulse interval periods, wherein the value range of the non-uniform pulse interval period is determined according to the blind spot position of the synthetic aperture radar not being within the imaging area.

[0009] The first obtaining module is used to reconstruct the echo signal in azimuth to obtain a reconstructed signal with uniform sampling interval, wherein the echo signal represents a signal with non-uniform azimuth sampling interval that is reflected back to the synthetic aperture radar after encountering a target and the transmitted signal sent by the synthetic aperture radar based on a pulse interval periodic sequence.

[0010] The second obtaining module is used to suppress interference on the reconstructed signal to obtain a target reconstructed signal.

[0011] The third obtaining module is used to reconstruct the target reconstructed signal in azimuth to obtain an image corresponding to the transmitted signal.

[0012] A third aspect of the present disclosure provides an electronic device, comprising: one or more processors; and a memory for storing one or more computer programs, wherein the one or more processors execute the one or more computer programs to implement the steps of the above method.

[0013] The fourth aspect of the present disclosure further provides a computer-readable storage medium having a computer program or instructions stored thereon, which implements the steps of the above method when the above computer program or instructions are executed by a processor.

[0014] The fifth aspect of the present disclosure further provides a computer program product, including a computer program or instructions, which implement the steps of the above method when the above computer program or instructions are executed by a processor.

[0015] According to the anti-deception interference imaging method, device and equipment of the synthetic aperture radar provided by the present invention, the pulse interval period sequence can be determined according to the value range and number of the non-uniform pulse interval period, and the directional position of the echo signal of the transmission signal sent based on the pulse interval period sequence can be reconstructed to obtain a reconstructed signal with uniform sampling interval, thereby achieving one-time interference suppression. Then, the reconstructed signal is subjected to interference suppression again to obtain a target reconstructed signal. Since the target reconstructed signal causes sampling omissions of some real echo signals, it is necessary to perform directional position reconstruction on the target reconstructed signal, so as to obtain a high-quality image corresponding to the transmission signal. Since the echo signal is subjected to interference suppression twice, the imaging quality is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above contents and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0017] Figure 1 The application scenario diagram of the anti-spoofing interference imaging of the synthetic aperture radar according to the embodiment of the present disclosure is schematically shown;

[0018] Figure 2 A flowchart of an anti-spoofing interference imaging method of a synthetic aperture radar according to an embodiment of the present disclosure is schematically shown;

[0019] Figure 3 Schematically shows a timing diagram of transmitting pulses and receiving pulses based on a non-uniform pulse interval period according to an embodiment of the present disclosure;

[0020] Figure 4A A timing diagram schematically shows a jammer forwarding interference with the largest non-uniform pulse interval period in the sequence PRI under the non-uniform pulse interval period according to an embodiment of the present disclosure;

[0021] Figure 4B A timing diagram schematically shows a jammer forwarding interference with an average pulse interval period in a sequence PRI under a non-uniform pulse interval period according to an embodiment of the present disclosure;

[0022] Figure 4C Schematically shows a timing diagram of a jammer updating a pulse interval period and forwarding interference according to a change of a non-uniform pulse interval period under a non-uniform pulse interval period according to an embodiment of the present disclosure;

[0023] Figure 5 A flowchart of an anti-spoofing interference imaging method of a synthetic aperture radar according to an embodiment of the present disclosure is schematically shown;

[0024] Figure 6 A schematic diagram of blind area distribution according to an embodiment of the present disclosure is shown schematically;

[0025] Figure 7 A schematic diagram of an imaging result of primary interference suppression according to an embodiment of the present disclosure is schematically shown;

[0026] Figure 8 A schematic diagram of determining an interference channel according to an embodiment of the present disclosure is schematically shown;

[0027] Fig.9A A schematic diagram of imaging results of a fixed pulse interval period according to an embodiment of the present disclosure is schematically shown;

[0028] Fig. 9B A schematic diagram of imaging results of a non-uniform pulse interval period according to an embodiment of the present disclosure is schematically shown;

[0029] Fig. 9C A schematic diagram of imaging results of a non-uniform pulse interval period according to another embodiment of the present disclosure is schematically shown;

[0030] Fig.10 A structural block diagram of an anti-spoofing interference imaging device of a synthetic aperture radar according to an embodiment of the present disclosure is schematically shown; and

[0031] Fig.11 A block diagram of an electronic device suitable for implementing an anti-spoofing interference imaging method for a synthetic aperture radar according to an embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0032] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0033] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0034] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0035] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0036] In the technical solution of the present disclosure, the user information (including but not limited to user personal information, user image information, user device information, such as location information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved are all information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of the relevant data comply with relevant laws, regulations and standards, take necessary confidentiality measures, do not violate public order and good morals, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0037] In the process of implementing the present disclosure, the anti-spoofing interference method in the related art is mainly based on the agility of pulse parameters. For example, based on the linear frequency modulation (LFM) waveform itself, parameter design is performed, and a mutually orthogonal LFM-PC waveform is obtained by adding phase coding (PC) to the LFM waveform. However, after the phase coding is introduced, a certain imaging performance is often sacrificed in order to ensure orthogonality. For another example, a waveform of a new system is directly introduced, and an orthogonal waveform is obtained by performing frequency domain diversity on the orthogonal frequency division multiplexing (OFDM) waveform. However, in order to obtain an OFDM orthogonal waveform set whose autocorrelation function and cross-correlation function meet the requirements, it is necessary to introduce complex optimization methods such as genetic algorithms to design frequency domain coding. In the above two methods, in order to ensure the anti-spoofing interference performance, a large number of mutually orthogonal waveforms need to be designed, which will make some waveforms unable to meet the constant modulus constraint conditions and difficult to implement through hardware. For another example, a method of transmitting signals using a variable PRI strategy to suppress deceptive interference by destroying the azimuth timing of the deceptive interference, and then introducing a frequency domain reconstruction method for azimuth non-uniform reconstruction. However, since the research on the variable PRI strategy and the non-uniform sampling reconstruction method are all conducted for high-resolution wide-band SAR, they are not completely applicable to anti-deceptive interference, and when the jammer adopts a certain forwarding method, some coherent interference will remain in the imaging results using the variable PRI strategy, resulting in poor imaging quality.

[0038] In view of this, an embodiment of the present disclosure provides an anti-deception interference imaging method for a synthetic aperture radar, comprising: in response to an anti-deception interference imaging request of the synthetic aperture radar, obtaining the number of non-uniform pulse interval periods; determining a pulse interval period sequence according to a value range of the non-uniform pulse interval period and the number of non-uniform pulse interval periods, wherein the value range of the non-uniform pulse interval period is determined according to the fact that the blind spot position of the synthetic aperture radar is not within the imaging area; reconstructing the echo signal in azimuth to obtain a reconstructed signal with uniform sampling interval, wherein the echo signal represents a signal with non-uniform azimuth sampling interval when a transmission signal sent by the synthetic aperture radar based on the pulse interval period sequence encounters a target and is reflected back to the synthetic aperture radar; performing interference suppression on the reconstructed signal to obtain a target reconstructed signal; and reconstructing the target reconstructed signal in azimuth to obtain an image corresponding to the transmission signal.

[0039] Figure 1 The application scenario diagram of the anti-spoofing interference imaging of the synthetic aperture radar according to the embodiment of the present disclosure is schematically shown.

[0040] like Figure 1 As shown, the application scenario 100 according to this embodiment may include a first terminal device 101, a second terminal device 102, a third terminal device 103, a network 104, and a server 105. The network 104 is used to provide a medium for a communication link between the first terminal device 101, the second terminal device 102, the third terminal device 103, and the server 105. The network 104 may include various connection types, such as wired, wireless communication links, or optical fiber cables, etc.

[0041] The user can use the first terminal device 101 , the second terminal device 102 , and the third terminal device 103 to interact with the server 105 through the network 104 to receive or send messages, etc.

[0042] The server 105 may be a server that provides various services.

[0043] It should be noted that the anti-deception interference imaging method of the synthetic aperture radar provided in the embodiment of the present disclosure can generally be executed by the server 105. Accordingly, the anti-deception interference imaging device of the synthetic aperture radar provided in the embodiment of the present disclosure can generally be set in the server 105. The anti-deception interference imaging method of the synthetic aperture radar provided in the embodiment of the present disclosure can also be executed by a server or server cluster that is different from the server 105 and can communicate with the first terminal device 101, the second terminal device 102, the third terminal device 103 and / or the server 105. Accordingly, the anti-deception interference imaging device of the synthetic aperture radar provided in the embodiment of the present disclosure can also be set in a server or server cluster that is different from the server 105 and can communicate with the first terminal device 101, the second terminal device 102, the third terminal device 103 and / or the server 105.

[0044] It should be understood that Figure 1 The number of the first terminal device, the second terminal device, the third terminal device, the network and the server in the embodiment is only for illustration. According to the implementation requirements, there may be any number of the first terminal device, the second terminal device, the third terminal device, the network and the server.

[0045] Figure 2 A flow chart of an anti-spoofing interference imaging method for a synthetic aperture radar according to an embodiment of the present disclosure is schematically shown.

[0046] like Figure 2 As shown, the anti-spoofing interference imaging method 200 of the synthetic aperture radar of this embodiment includes operations S210 to S250.

[0047] In operation S210 , in response to an anti-spoofing interference imaging request of a synthetic aperture radar, the number of non-uniform pulse interval periods is acquired.

[0048] In operation S220, a pulse interval period sequence is determined according to a value range of the non-uniform pulse interval period and the number of the non-uniform pulse interval periods.

[0049] In operation S230, the echo signal is reconstructed in azimuth to obtain a reconstructed signal with uniform sampling intervals.

[0050] In operation S240, interference suppression is performed on the reconstructed signal to obtain a target reconstructed signal.

[0051] In operation S250, the target reconstructed signal is reconstructed in azimuth to obtain an image corresponding to the transmitted signal.

[0052] According to the embodiments of the present disclosure, synthetic aperture radar can represent an advanced microwave remote sensing imaging radar system, which can perform high-resolution imaging of the ground all day and all weather under various weather conditions and lighting conditions. Synthetic aperture radar uses the echo effect between radar signals and targets for imaging. The imaging system based on synthetic aperture radar transmits broadband radar signals and receives signals reflected from ground targets, and infers the distance, speed and direction of the target based on the time delay and phase change of the signals.

[0053] According to an embodiment of the present disclosure, the pulse interval period may also be referred to as a pulse repetition period, which may characterize the time interval between two consecutive radar pulses. The pulse interval period may determine the frequency of radar pulse transmission, i.e., the pulse repetition frequency. The non-uniform pulse interval period may characterize that the time interval between multiple consecutive radar pulses is non-uniform.

[0054] According to an embodiment of the present disclosure, the number of non-uniform pulse interval periods can be obtained from the anti-spoofing interference imaging request of the synthetic aperture radar. For example, the number of non-uniform pulse interval periods can be M, and M can be 50. The synthetic aperture radar can repeatedly send a transmission signal with M non-uniform pulse interval periods. The synthetic aperture radar in this embodiment is a variable pulse interval synthetic aperture radar. The M non-uniform pulse interval periods can be expressed as a sequence PRI, as shown in the following formula (1).

[0055] (1)

[0056] Wherein, PRI represents the sequence PRI, Indicates the first pulse interval period, Indicates the second pulse interval period, Indicates the Mth pulse interval period.

[0057] According to the embodiment of the present disclosure, the M non-uniform pulse interval periods may be linear, that is, the synthetic aperture radar in the embodiment of the present disclosure uses M non-uniform pulse interval periods to send the transmission signal, which can be understood as the synthetic aperture radar using a variable PRI strategy to work, the number of non-uniform pulse interval periods in the sequence PRI is M, and the m+1th non-uniform pulse interval period is It can be expressed as the following formula (2).

[0058] (2)

[0059] in, Represents the difference between adjacent non-uniform pulse interval periods, represents the m+1th non-uniform pulse interval period, Represents the mth non-uniform pulse interval period, and the value range of m is [0, M-1].

[0060] According to an embodiment of the present disclosure, when the M non-uniform pulse intervals in the sequence PRI increase linearly, the difference between adjacent non-uniform pulse intervals is Greater than 0, the maximum value in the sequence PRI Can be , the minimum value in the sequence PRI Can be .

[0061] According to an embodiment of the present disclosure, the echo signal represents a signal with a non-uniform azimuth sampling interval that is reflected back to the synthetic aperture radar after the transmission signal sent by the synthetic aperture radar based on the pulse interval period sequence encounters the target. The blind spot position of the synthetic aperture radar can represent the area that the synthetic aperture radar cannot cover or effectively image during the imaging process. For example, since the transmission signal and the reception signal of the synthetic aperture radar cannot be performed at the same time, there is an area where the echo signal may conflict with the transmission signal, which is a blind spot position. The imaging area can represent the area that the synthetic aperture radar can effectively cover or image during the imaging process. Therefore, in order to prevent the blind spot position from appearing in the imaging area, it is necessary to constrain the value range of the non-uniform pulse interval period.

[0062] According to the embodiment of the present disclosure, based on the imaging principle of the synthetic aperture radar, the synthetic aperture radar cannot receive the echo signal when sending the transmission signal, thereby generating a blind area that affects the reception of the echo signal. The time range of the blind area generated by the k-th transmission signal is as follows: Formula (3).

[0063] (3)

[0064] in, It means that the transmission signal is sent using the sequence PRI with a cycle of M. Indicates the duration of the transmitted signal.

[0065] Figure 3 The timing diagram of the transmission pulse and the reception pulse based on the non-uniform pulse interval period according to the embodiment of the present disclosure is schematically shown.

[0066] like Figure 3 As shown in the figure, TX represents the timing diagram of the transmitted pulse, RX1 represents the pulse receiving timing at the closest distance to the synthetic aperture radar in the imaging scene, and RX2 represents the pulse receiving timing at the farthest distance from the synthetic aperture radar in the imaging scene. In order to prevent the blind spot from appearing in the imaging area, the first non-uniform pulse interval period needs to be The echo of the transmitted pulse sent within is constrained to be within the kth non-uniform pulse interval period The receiving window of Indicates the transmit pulse being sent when the echo of the first transmit pulse is received.

[0067] According to the embodiments of the present disclosure, by combining the above formula (3) and the round-trip delay of the echo signal, the constraint of the non-uniform pulse interval period can be obtained, as shown in the following formula (4).

[0068] (4)

[0069] in, represents the maximum value of the shortest slant distance in the imaging area, represents the minimum value of the shortest slant distance in the imaging area, and c represents the speed of light.

[0070] According to the embodiment of the present disclosure, in order to ensure the azimuth resolution of the synthetic aperture radar, the average pulse interval period of the non-uniform pulse interval period is as small as possible from the fixed pulse interval period in the related art, so the fixed pulse interval period can be used to infer The size of is as follows formula (5).

[0071] (5)

[0072] in, is the shortest slant distance from the center of the imaging area, represents the fixed pulse interval period in the related art, is the floor function.

[0073] According to an embodiment of the present disclosure, by simplifying the above formula (5), the value range (6) of the non-uniform pulse interval period can be obtained.

[0074] (6)

[0075] According to an embodiment of the present disclosure, when the value range of the non-uniform pulse interval period and the number of the non-uniform pulse interval periods are determined, a pulse interval period sequence can be determined. When the value range of the non-uniform pulse interval period is determined, each non-uniform pulse interval period in the sequence PRI satisfies the value range, and combined with the number of non-uniform pulse interval periods, a pulse interval period sequence can be obtained, and the pulse interval period sequence will not cause the echo signal to be missing due to the blind spot position.

[0076] According to an embodiment of the present disclosure, azimuth reconstruction can represent the process of recovering a signal or Doppler spectrum with uniform sampling interval from an echo signal with non-uniform azimuth sampling interval. Since the synthetic aperture radar uses a linear pulse interval period to send a transmission signal, the azimuth sampling interval of the echo signal is non-uniform. By reconstructing the echo signal in azimuth, a reconstructed signal with uniform sampling interval can be obtained.

[0077] According to the embodiments of the present disclosure, after completing the azimuth reconstruction of the echo signal with non-uniform azimuth sampling interval, the echo signal can be processed in the range direction, and after completing the range processing, the echo signal can be subjected to secondary interference suppression. The secondary interference suppression process for the echo signal is to first perform interference detection, determine the channel where the interference exists, and then eliminate the echo signal of the interference channel, so as to achieve interference suppression for the reconstructed signal, further reduce the interference signal in the signal, and thus obtain the target reconstructed signal.

[0078] According to the embodiments of the present disclosure, since the echo signal of the interference channel contains not only interference signals but also real echo signals, eliminating the echo signal of the interference channel will cause sampling missing of the real echo signal, thereby requiring azimuth reconstruction of the target reconstructed signal, and then an image corresponding to the transmitted signal can be obtained.

[0079] According to the embodiments of the present disclosure, by determining the pulse interval period sequence based on the value range and number of the non-uniform pulse interval period, the directional position of the echo signal of the transmission signal sent based on the pulse interval period sequence can be reconstructed to obtain a reconstructed signal with uniform sampling intervals, thus achieving one-time interference suppression. Then, the reconstructed signal is subjected to interference suppression again to obtain a target reconstructed signal. Since the target reconstructed signal causes sampling omissions of some real echo signals, it is necessary to perform directional position reconstruction on the target reconstructed signal, to obtain a high-quality image corresponding to the transmission signal. Since the echo signal is subjected to interference suppression twice, the imaging quality is improved.

[0080] According to an embodiment of the present disclosure, an echo signal is reconstructed in azimuth to obtain a reconstructed signal with a uniform sampling interval, including: determining the time domain signals of each of the M channels based on the azimuth echo signal; performing Fourier transform on the time domain signals of each of the M channels to obtain the frequency domain signals of each of the M channels; and determining the reconstructed signals of each of the M channels with a uniform sampling interval based on the frequency domain signals of each of the M channels.

[0081] According to an embodiment of the present disclosure, the echo signal may include an azimuth echo signal, and the azimuth echo signal may include M channels. Since the transmission signal sent by the synthetic aperture radar is repeatedly sent in a sequence PRI, the sequence PRI contains M linearly varying non-uniform pulse interval periods, and each non-uniform pulse interval period may correspond to a channel, the azimuth echo signal may be equivalent to the superposition of M uniformly sampled channels.

[0082] According to an embodiment of the present disclosure, when a synthetic aperture radar sends a transmission signal in a sequence PRI, the azimuth sampling interval of the echo signal will be uneven, and the azimuth pulse transmission timing is as follows: Formula (7).

[0083] (7)

[0084] in, represents the number of synthetic aperture radar azimuth sampling points, Indicates the first azimuth pulse, Indicates the second azimuth pulse, Indicates the nth azimuth pulse.

[0085] According to an embodiment of the present disclosure, the kth azimuth pulse , as shown in formula (8).

[0086] (8)

[0087] The value range of k is [1,Na].

[0088] According to the embodiments of the present disclosure, after obtaining the echo signal, directly using the synthetic aperture radar imaging method in the related art to perform azimuth matched filtering will cause the signal to be unable to focus and have larger side lobes. Therefore, it is necessary to reconstruct the echo signal of non-uniform time sequence in azimuth. The detailed process of azimuth reconstruction will be introduced below.

[0089] According to the embodiment of the present disclosure, the time domain signals of the M channels can be obtained according to the azimuth echo signal. , as shown in formula (9).

[0090] (9)

[0091] in, represents the sampling interval of the ith channel, that is, the sum of all non-uniform pulse intervals in the sequence PRI, represents the noise in the ith channel, Indicates an ideal continuous signal in azimuth. Indicates the delay of the i-th channel relative to the reference channel, where the first channel is the reference channel.

[0092] According to the embodiment of the present disclosure, by performing Fourier transform on the time domain signals of the M channels, the frequency domain signals of the M channels can be obtained. For the time domain signal of the i-th channel, as shown in the above formula (9), Fourier transform is performed to obtain the frequency domain signal of the i-th channel , as shown in formula (10).

[0093] (10)

[0094] in, Indicates the preset uniform spectrum, represents the noise spectrum of the ith channel, where , Represents the phase shift in the frequency domain caused by the time domain delay.

[0095] According to an embodiment of the present disclosure, based on the frequency domain signals of each of the M channels, reconstructed signals with uniform sampling intervals of each of the M channels are determined, including: based on the frequency domain signals of each of the M channels, by rewriting the above formula (10) into a matrix form, the uniform echo matrix and frequency domain weighting matrix of the M channels can be determined, as shown in the following formulas (11) and (12).

[0096] (11)

[0097] (12)

[0098] in, represents the uniform echo matrix of M channels, represents the preset uniform spectrum matrix, represents the noise matrix of M channels, represents the frequency domain weighting matrix.

[0099] According to the embodiment of the present disclosure, the frequency domain weighting matrix can be inverted according to the frequency domain weighting matrix and the number of non-uniform pulse interval periods to obtain the reconstruction matrix of M channels. , as shown in formula (13).

[0100] (13)

[0101] in, Represents the transpose of the frequency-domain weighting matrix.

[0102] According to the embodiment of the present disclosure, based on the reconstruction matrix, the uniform echo matrix, the preset uniform spectrum matrix and the frequency domain weighting matrix, by combining the above formula (11) and formula (13), the uniformly sampled spectrum matrix can be obtained: , as shown in formula (14).

[0103] (14)

[0104] According to the embodiments of the present disclosure, a reconstructed signal with uniform sampling intervals can be obtained by performing an inverse Fourier transform on the frequency spectrum matrix.

[0105] According to the embodiments of the present disclosure, when the synthetic aperture radar adopts the variable PRI strategy to work, the jammer will not be able to accurately predict the transmission time of the next transmission signal of the synthetic aperture radar, so when generating deceptive interference, the fastest way is to use the last pulse interval period of the synthetic aperture radar to forward the interference signal. This will make the azimuth timing of the jammer no longer the same as that of the synthetic aperture radar, so that the deceptive interference signal is dispersed to different distances, and false targets can no longer be formed when processing in the azimuth direction, and the suppression of deceptive interference is initially achieved, that is, primary interference suppression.

[0106] According to the embodiments of the present disclosure, by performing Fourier transform on the time domain signals of each of the M channels, the frequency domain signals of each of the M channels can be obtained. By performing azimuth reconstruction on the frequency domain signals, a reconstructed signal with uniform sampling intervals can be obtained, thereby achieving primary interference suppression on the echo signal and improving the quality of the echo signal.

[0107] According to the embodiments of the present disclosure, after completing the azimuth reconstruction of the echo signal, the two-dimensional echo signal can be processed in the range direction. Since the synthetic aperture radar adopts a working mode of a variable PRI strategy, the jammer can detect different pulse interval periods. When it uses different pulse interval periods to forward interference, the interference patterns formed in the range pulse compression results are also different. Generally, the forwarding strategy of the jammer can be divided into the following three situations: the first jammer detects the largest non-uniform pulse interval period in the sequence PRI, and uses this as a fixed pulse interval period for interference forwarding; the second jammer detects a value in the sequence PRI that is close to or equal to the average pulse interval period, and then uses this pulse interval period for interference forwarding; the third jammer can update its own pulse interval period following the change of the non-uniform pulse interval period of the synthetic aperture radar, that is, the jammer selects the previous non-uniform pulse interval period of the synthetic aperture radar as its current pulse interval period.

[0108] Figure 4A The timing diagram schematically shows a jammer forwarding interference with the largest non-uniform pulse interval period in the sequence PRI under the non-uniform pulse interval period according to an embodiment of the present disclosure. Figure 4B The timing diagram schematically shows a jammer forwarding interference with an average pulse interval period in the sequence PRI under a non-uniform pulse interval period according to an embodiment of the present disclosure. Figure 4CA timing diagram schematically shows a jammer updating the pulse interval period and forwarding interference according to the change of the non-uniform pulse interval period under the non-uniform pulse interval period according to an embodiment of the present disclosure.

[0109] like Figure 4A As shown in FIG. 1 , the synthetic aperture radar uses the sequence PRI to periodically send the transmission signal, and the jammer uses the largest non-uniform pulse interval period in the sequence PRI as the fixed pulse interval period to forward the interference timing diagram, as shown in FIG. Figure 4B As shown in FIG. 1 , the synthetic aperture radar uses the sequence PRI to periodically send the transmission signal, and the jammer uses the average pulse interval period in the sequence PRI as the fixed pulse interval period to forward the interference timing diagram, as shown in FIG. Figure 4C As shown, it is a timing diagram that the synthetic aperture radar uses the sequence PRI to periodically send the transmission signal, and the jammer updates its own pulse interval period following the non-uniform pulse interval period to forward the interference.

[0110] like Figures 4A to 4C As shown, when the synthetic aperture radar uses the sequence PRI with a period of 50, the azimuth time accumulation of interference and SAR and the difference between them under the forwarding interference strategy of the three jammers can be seen. Figure 4B and Figure 4C In the example, the timing of the transmitting signal and the timing of the interference signal almost coincide.

[0111] According to the embodiment of the present disclosure, the azimuth timing difference between the jammer and the synthetic aperture radar determines the distance offset of the false target. When the jammer uses the maximum non-uniform pulse interval period of the synthetic aperture radar as its own forwarding interval, Figure 4A As shown in the figure, since the pulse interval period of the jammer is greater than the average pulse interval period of the synthetic aperture radar, the azimuth timing accumulation of the two will become more and more different, resulting in the original azimuth coherent interference signal being randomly dispersed to different distance directions, and no longer forming coherent interference. When the jammer selects the average pulse interval period of the synthetic aperture radar as its own pulse interval period or follows the non-uniform pulse interval period change, as shown in the figure, Figure 4B and 4C As shown in the figure, since the average pulse interval period of the jammer and the synthetic aperture radar is the same, the azimuth timing difference between the jammer and the synthetic aperture radar changes periodically, which causes the azimuth envelope of the jammer to be dispersed to certain fixed distances. At these distances, the jammer still has a certain coherence. Therefore, for the latter two forwarding jamming strategies, it is still necessary to suppress the residual interference. The process of secondary interference suppression will be described in detail below.

[0112] According to an embodiment of the present disclosure, interference suppression is performed on a reconstructed signal to obtain a target reconstructed signal, including: filtering the reconstructed signals of M channels to obtain a first pulse compression result; setting the reconstructed signal of one of the M channels to zero in turn and then filtering to obtain M second pulse compression results; obtaining interference coefficients of the M channels based on the first pulse compression result and the M second pulse compression results; determining an interference channel based on the interference coefficients of the M channels and a preset interference threshold; and determining a target reconstructed signal based on the reconstructed signal corresponding to the interference channel and the reconstructed signals of the M channels.

[0113] According to the embodiments of the present disclosure, since the synthetic aperture radar uses a sequence PRI with a period of M for imaging, the azimuth echo signal of the synthetic aperture radar can be understood as a combination of M uniform sampling channels. Figure 4B and 4C As shown in the figure, the period of the synthetic aperture radar is 50. It can be found that under these two forwarding interference strategies, the difference between the interference and the azimuth timing of the synthetic aperture radar also changes periodically with a period of 50. In the case where a certain distance contains interference, at least all the interference of a certain channel is included. For the interference contained in the i-th channel , as shown in formula (15).

[0114] (15)

[0115] in, is the continuous deception jamming envelope in azimuth direction, Indicates The delay of the channel with respect to the reference channel.

[0116] According to an embodiment of the present disclosure, since the interference of a certain channel is coherent, secondary interference suppression is performed on the echo signal.

[0117] According to the embodiment of the present disclosure, the reconstructed signals of the M channels are first compressed to obtain a pulse compression result including a real signal and an interference signal, that is, a first pulse compression result , as shown in formula (16).

[0118] (16)

[0119] in, is the azimuth matched filter, represents the inverse Fourier transform, represents Fourier transform.

[0120] According to the embodiment of the present disclosure, by setting the reconstructed signal of one of the M channels to zero in sequence and then filtering, M second pulse compression results can be obtained. That is, by successively discarding the signal of a certain channel and then performing pulse compression, M second pulse compression results can be obtained. The signal of the i-th channel of the reconstructed signal is set to zero, and is recorded as , and then matched filtering is performed to obtain the pulse compression result of the remaining channel of the reconstructed signal , as shown in formula (17).

[0121] (17)

[0122] According to an embodiment of the present disclosure, when interference exists in the i-th channel, Compared to After discarding the interference energy, we can calculate and The interference coefficient of the i-th channel is represented by the energy difference of , as shown in formula (18).

[0123] (18)

[0124] According to an embodiment of the present disclosure, M second pulse compression results are compared with the first pulse compression results to detect whether there are interference signals in the M channels, that is, the interference coefficients of the M channels are calculated one by one, the variances of the interference coefficients in all distance directions are calculated, and then their sizes are compared. A higher level of the variance of the interference coefficient can indicate the presence of interference in the distance direction.

[0125] According to an embodiment of the present disclosure, an interference channel is determined based on interference coefficients of M channels and a preset interference threshold, including: comparing the interference coefficients of the M channels with the preset interference value, and determining M coefficient differences between the interference coefficients of the M channels and the preset interference coefficient; when the interference coefficient exceeds the preset interference threshold, that is, the M coefficient differences are greater than 0, determining the channel corresponding to the coefficient difference greater than 0 among the M coefficient differences as the interference channel, so that the interference distribution of the M channels can be obtained, that is, the interference channel is determined.

[0126] According to an embodiment of the present disclosure, the range direction may include a plurality of range units, and a preset interference threshold may be set for the azimuth direction of each range unit.

[0127] According to an embodiment of the present disclosure, a target reconstructed signal is determined based on a reconstructed signal corresponding to an interference channel and reconstructed signals of M channels, including: the reconstructed signal corresponding to the interference channel can be removed from the reconstructed signals of the M channels to obtain the target reconstructed signal.

[0128] According to an embodiment of the present disclosure, a first pulse compression result can be obtained by filtering the reconstructed signals of M channels, and then the reconstructed signals of any one of the M channels are set to zero in turn and then filtered to obtain a second pulse compression result of the M channels. The first pulse result and the second pulse compression result are compared to determine the interference coefficients of the M channels, and the interference coefficients of the M channels are compared with the preset interference coefficients to determine the interfering channels with interference. The reconstructed signals of the interfering channels are removed from the reconstructed signals of the M channels to obtain the target reconstructed signal, thereby achieving primary interference suppression of the echo signal and improving the quality of the echo signal.

[0129] According to an embodiment of the present disclosure, the target reconstruction signal is reconstructed in azimuth to obtain an image corresponding to the transmitted signal, including: constructing an azimuth imaging operator according to the target reconstruction signal and a preset azimuth inverse Fourier transform matrix; constructing an azimuth imaging inverse operator according to a preset azimuth Fourier transform matrix, a preset initial imaging result, a preset azimuth matched filter matrix, and a preset azimuth inverse matched filter matrix; according to the azimuth imaging operator and the azimuth imaging inverse operator, using a threshold iteration algorithm to iterate the initial imaging result to obtain an image corresponding to the transmitted signal.

[0130] According to the embodiments of the present disclosure, when the reconstructed signal of the interference channel is removed, not only the interference signal is removed, but also the real echo signal is removed, resulting in missing samples of the real echo signal. In order to avoid signal distortion and increased side lobes, a sparse synthetic aperture radar imaging method is introduced to perform azimuth reconstruction.

[0131] According to an embodiment of the present disclosure, an azimuth imaging operator can be constructed according to the target reconstruction signal and the preset azimuth inverse Fourier transform matrix, as shown in the following formula (19). An azimuth imaging inverse operator can be constructed according to the preset azimuth Fourier transform matrix, the preset initial imaging result, the preset azimuth matched filter matrix, and the preset azimuth inverse matched filter matrix, as shown in the following formula (20).

[0132] (19)

[0133] (20)

[0134] in, represents the azimuth imaging operator, represents the azimuth imaging inverse operator, Represents the preset azimuth Fourier transform matrix, represents the preset azimuth inverse Fourier transform matrix, represents the preset azimuth matched filter matrix, represents the preset azimuth inverse matched filter matrix, represents the target reconstruction signal, represents the initial imaging results.

[0135] According to an embodiment of the present disclosure, an initial imaging result is iterated using a threshold iteration algorithm according to an azimuth imaging operator and an azimuth imaging inverse operator to obtain an image corresponding to the transmitted signal, including: constructing a sparse signal model according to the azimuth imaging operator and the azimuth imaging inverse operator; according to the sparse signal model, iterating a preset initial imaging result using a threshold iteration algorithm until the number of iterations reaches the maximum number of iterations or the residual is less than an error parameter, thereby obtaining an image corresponding to the transmitted signal.

[0136] According to the embodiments of the present disclosure, a sparse signal model can be constructed based on the constructed azimuth imaging operator and imaging inverse operator. By iterating the initial imaging result using the sparse signal model, an image corresponding to the transmitted signal can be obtained, thereby improving image quality.

[0137] According to the embodiments of the present disclosure, compared with the anti-deception interference method using waveform design in the related art, by adopting the variable PRI strategy for anti-deception interference, the complexity introduced to the synthetic aperture radar hardware system is lower, which is more conducive to hardware implementation. And the variable PRI strategy will not cause the loss of effective echo signals in the imaging area, which can reduce the pressure of subsequent imaging processing. Then, for the partial coherence of the deception interference that still remains after the variable PRI strategy processing, secondary interference suppression is performed after the range processing, which can effectively remove the residual interference dispersed by the variable PRI strategy. Finally, a one-dimensional sparse reconstruction method is used for azimuth processing, and finally high-precision synthetic aperture radar imaging is achieved while suppressing deception interference.

[0138] Figure 5 A flow chart of an anti-spoofing interference imaging method for a synthetic aperture radar according to an embodiment of the present disclosure is schematically shown.

[0139] like Figure 5 As shown, the anti-spoofing interference imaging method 500 of the synthetic aperture radar of this embodiment includes operations S510 to S570.

[0140] In operation S510 , the synthetic aperture radar sends a transmission signal using a variable pulse interval period strategy.

[0141] In operation S520, range pulse compression is performed on the received echo signal.

[0142] In operation S530, azimuthally non-uniform reconstruction is performed based on a multi-channel principle.

[0143] In operation S540, the distance is corrected to a free-falling state.

[0144] In operation S550, secondary interference suppression is performed based on a multi-channel principle.

[0145] In operation S560, azimuth one-dimensional sparse reconstruction is performed.

[0146] In operation S570, an anti-interference high-precision imaging result is obtained.

[0147] According to the embodiments of the present disclosure, when the synthetic aperture radar adopts the variable PRI strategy to transmit signals, the jammer can still retain a certain coherence when using the average pulse interval period of the synthetic aperture radar or following the non-uniform pulse interval period change of the synthetic aperture radar to forward the interference, which poses a greater threat to the synthetic aperture radar imaging. Therefore, in this embodiment, taking the jammer using the average pulse interval period of the synthetic aperture radar to forward the interference as an example, the anti-deception interference and high-precision imaging capabilities of the above-mentioned synthetic aperture radar are analyzed. The parameters of the synthetic aperture radar are shown in Table 1.

[0148] Table 1 Synthetic aperture radar imaging parameters

[0149]

[0150] According to the embodiment of the present disclosure, the shortest slant distance to the center of the imaging area can be obtained according to the above Table 1: , the strip width is , thus obtaining the maximum value in the sequence PRI for , the minimum value in the sequence PRI for , substituting into the above formula (5) and formula (6), we can get the value range of the pulse interval period, and then let the number of pulse interval periods be , a set of pulse interval periods that meet the requirements can be obtained, namely the sequence PRI.

[0151] Figure 6 A schematic diagram of blind area distribution according to an embodiment of the present disclosure is schematically shown.

[0152] like Figure 6 The figure shows the blind area distribution diagram of the synthetic aperture radar imaging scene. The black part represents the distribution area of ​​the blind area, and the gray part represents the strip imaging area. It can be seen that the blind areas obtained by using the variable PRI strategy are all distributed outside the imaging area, which does not cause the loss of effective signals and can reduce the pressure of subsequent imaging processing.

[0153] Figure 7 A schematic diagram of an imaging result of a primary interference suppression according to an embodiment of the present disclosure is schematically shown.

[0154] like Figure 7As shown in the figure, it shows the interference effect formed in the imaging scene when the interference is forwarded by the average pulse interval period of the synthetic aperture radar. The continuous envelope located in the middle of the scene is the azimuth envelope of the real target, while the azimuth discrete envelopes distributed in different distance directions are the interference signals dispersed due to the variable PRI strategy. It can be found that when the jammer uses the average pulse interval period of the synthetic aperture radar to forward the interference, the interference is indeed dispersed to certain fixed distances, but still retains a certain coherence, so secondary interference suppression is required.

[0155] Figure 8 A schematic diagram of determining an interference channel according to an embodiment of the present disclosure is schematically shown.

[0156] like Figure 8 As shown, select Figure 7 By calculating the azimuth envelope of a residual interference in different channels and calculating the interference coefficients of different channels, it can be found that the interference detection coefficients of channels 13 and 39 are significantly different from those of other channels, indicating that there is interference in channels 13 and 39. Therefore, the interference coefficient is used to successfully detect the channel where the interference is located.

[0157] According to the embodiment of the present disclosure, after removing the signals of the two channels, channel 13 and channel 39, one-dimensional reconstruction is performed in azimuth. Using the sparse imaging method, even if the real signals of some channels are lost, a good imaging result can be obtained.

[0158] Fig.9A The figure schematically shows the imaging result of a fixed pulse interval period according to an embodiment of the present disclosure. Fig. 9B The figure schematically shows the imaging result of the non-uniform pulse interval period according to the embodiment of the present disclosure. Fig. 9C A schematic diagram of imaging results of a non-uniform pulse interval period according to yet another embodiment of the present disclosure is schematically shown.

[0159] like Figures 9A to 9C As shown in the figure, the imaging results of point targets in a deception jamming environment are shown respectively when a fixed pulse interval period is used, when a variable PRI strategy is used without secondary suppression, and when a variable PRI strategy is used with secondary suppression completed. Fig.9A As shown in the figure, in the imaging results with a fixed pulse interval, the deception interference cannot be suppressed, the imaging result of the real point target is located in the center of the imaging scene, and the multiple false targets located around it are also clearly visible. Fig. 9BAs shown in the figure, after adopting the variable PRI strategy, the false point target is successfully suppressed, but at the same time, the influence of deception interference does not completely disappear, but forms discrete point target interference distributed along the azimuth direction in some distance directions, which still affects the imaging results. Therefore, the residual interference suppression method based on the multi-channel principle is used for secondary interference suppression, and the one-dimensional sparse reconstruction method is introduced for azimuth processing. The final imaging result is shown in the figure. Fig. 9C As shown, only the imaging results of the real target are retained in the imaging area, the deception interference is completely eliminated, and high-precision imaging is achieved.

[0160] According to the embodiments of the present disclosure, two-dimensional interference suppression ratio (ISR) and signal-to-distortion ratio (SDR) are introduced as evaluation indicators of anti-spoofing interference effect for analysis. As shown in formula (21), the signal distortion ratio As shown in formula (22).

[0161] (twenty one)

[0162] (twenty two)

[0163] in, represents the imaging result without interference suppression. represents the imaging result after interference suppression, Indicates interference-free imaging results.

[0164] According to an embodiment of the present disclosure, the calculation Figures 9A to 9CThe anti-interference indicators of the three imaging results are shown in Table 2. The larger the ISR, the better the interference suppression effect. When the pulse interval period strategy is fixed, the ISR is 0dB, indicating that the interference cannot be suppressed at all; after the variable PRI strategy is introduced, the ISR is increased to 7.51dB, indicating that the variable PRI strategy plays a role in suppressing interference; and on this basis, the secondary interference suppression is carried out, which increases the ISR by about 2dB, indicating that the secondary interference suppression further improves the interference suppression ability. The combination of the two makes the ISR reach 9.78dB, and the interference suppression effect is good. SDR is used to characterize the degree of image distortion. The smaller the SDR, the smaller the difference between the imaging result under interference conditions and the real target. When the fixed pulse interval strategy is adopted, the SDR is 10.20dB. After the variable PRI strategy is introduced, the SDR is reduced to 6.88dB, indicating that the variable PRI strategy reduces the signal distortion caused by deception interference. After the subsequent secondary interference suppression and azimuth sparse reconstruction, the SDR is greatly reduced to -38.79dB, indicating that the imaging results after the PRI strategy and secondary suppression and sparse reconstruction are very different from the real target, and high-precision imaging is achieved while suppressing deception interference.

[0165] Table 2 Anti-interference index of point target imaging results

[0166]

[0167] Based on the above-mentioned synthetic aperture radar anti-deception interference imaging method, the present disclosure also provides a synthetic aperture radar anti-deception interference imaging device. Fig.10 The device is described in detail.

[0168] Fig.10 The structural block diagram of the anti-deception interference imaging device of the synthetic aperture radar according to an embodiment of the present disclosure is schematically shown.

[0169] like Fig.10 As shown, the anti-deception interference imaging device 1000 of the synthetic aperture radar of this embodiment includes an acquisition module 1010, a determination module 1020, a first obtaining module 1030, a second obtaining module 1040 and a third obtaining module 1050.

[0170] The acquisition module 1010 is used to obtain the number of non-uniform pulse interval periods in response to the anti-spoofing jamming imaging request of the synthetic aperture radar. In one embodiment, the acquisition module 1010 can be used to perform the operation S210 described above, which will not be described in detail here.

[0171] The determination module 1020 is used to determine the pulse interval period sequence according to the value range of the non-uniform pulse interval period and the number of the non-uniform pulse interval periods, wherein the value range of the non-uniform pulse interval period is determined according to the blind spot position of the synthetic aperture radar not being within the imaging area. In one embodiment, the determination module 1020 can be used to perform the operation S220 described above, which will not be repeated here.

[0172] The first obtaining module 1030 is used to reconstruct the echo signal in azimuth to obtain a reconstructed signal with uniform sampling interval, wherein the echo signal represents a signal with non-uniform azimuth sampling interval when the transmission signal sent by the synthetic aperture radar based on the pulse interval period sequence encounters the target and is reflected back to the synthetic aperture radar. In one embodiment, the first obtaining module 1030 can be used to perform the operation S230 described above, which will not be repeated here.

[0173] The second obtaining module 1040 is used to perform interference suppression on the reconstructed signal to obtain a target reconstructed signal. In one embodiment, the second obtaining module 1040 can be used to perform the operation S240 described above, which will not be described in detail here.

[0174] The third obtaining module 1050 is used to perform azimuth reconstruction on the target reconstructed signal to obtain an image corresponding to the transmitted signal. In one embodiment, the third obtaining module 1050 can be used to perform the operation S250 described above, which will not be described in detail here.

[0175] According to an embodiment of the present disclosure, the echo signal includes an azimuth echo signal, the azimuth echo signal includes M channels, and the first obtaining module 1030 includes: a first obtaining submodule, a second obtaining submodule and a third obtaining submodule.

[0176] The first obtaining submodule is used to determine the time domain signals of the M channels according to the azimuth echo signal.

[0177] The second obtaining submodule is used to perform Fourier transform on the time domain signals of the M channels to obtain the frequency domain signals of the M channels.

[0178] The third obtaining submodule is used to determine the reconstructed signals with uniform sampling intervals for the M channels according to the frequency domain signals of the M channels.

[0179] According to an embodiment of the present disclosure, the third obtaining submodule includes: a first obtaining unit, a second obtaining unit, a third obtaining unit and a fourth obtaining unit.

[0180] The first obtaining unit is used to determine the uniform echo matrix and the frequency domain weighting matrix of the M channels according to the frequency domain signals of the M channels respectively.

[0181] The second obtaining unit is used to obtain the reconstruction matrix of M channels according to the frequency domain weighting matrix and the number of pulse interval periods.

[0182] The third obtaining unit is used to determine a spectrum matrix with uniform sampling intervals according to the reconstruction matrix, the uniform echo matrix, the preset uniform spectrum matrix and the frequency domain weighting matrix.

[0183] The fourth obtaining unit is used to perform inverse Fourier transform on the spectrum matrix to obtain reconstructed signals with uniform sampling intervals for the M channels.

[0184] According to an embodiment of the present disclosure, the second obtaining module 1040 includes: a fourth obtaining submodule, a fifth obtaining submodule, a sixth obtaining submodule, a seventh obtaining submodule and an eighth obtaining submodule.

[0185] The fourth obtaining submodule is used to filter the reconstructed signals of the M channels to obtain a first pulse compression result.

[0186] The fifth obtaining submodule is used to sequentially set the reconstructed signal of one of the M channels to zero and then filter it to obtain M second pulse compression results.

[0187] The sixth obtaining submodule is used to obtain interference coefficients of M channels according to the first pulse compression result and the M second pulse compression results.

[0188] The seventh obtaining submodule is used to determine the interference channel according to the interference coefficients of the M channels and the preset interference threshold.

[0189] The eighth obtaining submodule is used to determine the target reconstructed signal according to the reconstructed signal corresponding to the interference channel and the reconstructed signals of the M channels.

[0190] According to an embodiment of the present disclosure, the seventh obtaining submodule includes: a fifth obtaining unit and a sixth obtaining unit.

[0191] The fifth obtaining unit is used to determine M coefficient differences between the interference coefficients of the M channels and the preset interference coefficient according to the interference coefficients of the M channels and the preset interference coefficient.

[0192] The sixth obtaining unit is used to determine the channel corresponding to the coefficient difference value greater than 0 among the M coefficient differences as an interference channel.

[0193] According to an embodiment of the present disclosure, the eighth obtaining submodule includes: a seventh obtaining unit.

[0194] The seventh obtaining unit is used to remove the reconstructed signal corresponding to the interference channel from the reconstructed signals of the M channels to obtain the target reconstructed signal.

[0195] According to an embodiment of the present disclosure, the third obtaining module 1050 includes: a ninth obtaining submodule, a tenth obtaining submodule and an eleventh obtaining submodule.

[0196] The ninth obtaining submodule is used to construct an azimuth imaging operator according to the target reconstruction signal and a preset azimuth inverse Fourier transform matrix.

[0197] The tenth obtaining submodule is used to construct an azimuth imaging inverse operator according to a preset azimuth Fourier transform matrix, a preset initial imaging result, a preset azimuth matched filter matrix, and a preset azimuth inverse matched filter matrix.

[0198] The eleventh obtaining submodule is used to iterate the initial imaging result using a threshold iteration algorithm according to the azimuth imaging operator and the azimuth imaging inverse operator to obtain an image corresponding to the emission signal.

[0199] According to an embodiment of the present disclosure, the eleventh obtaining submodule includes: an eighth obtaining unit and a ninth obtaining unit.

[0200] The eighth obtaining unit is used to construct a sparse signal model according to the azimuth imaging operator and the azimuth imaging inverse operator.

[0201] The ninth obtaining unit is used to iterate the preset initial imaging result by using a threshold iteration algorithm according to the sparse signal model to obtain an image corresponding to the emission signal.

[0202] According to an embodiment of the present disclosure, any multiple modules of the acquisition module 1010, the determination module 1020, the first acquisition module 1030, the second acquisition module 1040, and the third acquisition module 1050 can be combined in one module for implementation, or any one of the modules can be split into multiple modules. Alternatively, at least part of the functions of one or more of these modules can be combined with at least part of the functions of other modules and implemented in one module. According to an embodiment of the present disclosure, at least one of the acquisition module 1010, the determination module 1020, the first acquisition module 1030, the second acquisition module 1040, and the third acquisition module 1050 can be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on a chip, a system on a substrate, a system on a package, an application specific integrated circuit (ASIC), or can be implemented by hardware or firmware such as any other reasonable way of integrating or packaging the circuit, or implemented in any one of the three implementation methods of software, hardware, and firmware, or in any appropriate combination of any of them. Alternatively, at least one of the acquisition module 1010, the determination module 1020, the first obtaining module 1030, the second obtaining module 1040 and the third obtaining module 1050 may be at least partially implemented as a computer program module, which may perform a corresponding function when executed.

[0203] Fig.11 A block diagram of an electronic device suitable for implementing an anti-spoofing interference imaging method for a synthetic aperture radar according to an embodiment of the present disclosure is schematically shown.

[0204] like Fig.11 As shown, the electronic device 1100 according to an embodiment of the present disclosure includes a processor 1101, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1102 or a program loaded from a storage part 1108 to a random access memory (RAM) 1103. The processor 1101 may include, for example, a general-purpose microprocessor (such as a CPU), an instruction set processor and / or a related chipset and / or a special-purpose microprocessor (for example, an application-specific integrated circuit (ASIC)), etc. The processor 1101 may also include an onboard memory for caching purposes. The processor 1101 may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present disclosure.

[0205] In RAM 1103, various programs and data required for the operation of electronic device 1100 are stored. Processor 1101, ROM 1102 and RAM 1103 are connected to each other through bus 1104. Processor 1101 performs various operations of the method flow according to the embodiment of the present disclosure by executing the program in ROM 1102 and / or RAM 1103. It should be noted that the program can also be stored in one or more memories other than ROM 1102 and RAM 1103. Processor 1101 can also perform various operations of the method flow according to the embodiment of the present disclosure by executing the program stored in the one or more memories.

[0206] According to an embodiment of the present disclosure, the electronic device 1100 may further include an input / output (I / O) interface 1105, which is also connected to the bus 1104. The electronic device 1100 may further include one or more of the following components connected to the input / output (I / O) interface 1105: an input portion 1106 including a keyboard, a mouse, etc.; an output portion 1107 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage portion 1108 including a hard disk, etc.; and a communication portion 1109 including a network interface card such as a LAN card, a modem, etc. The communication portion 1109 performs communication processing via a network such as the Internet. A drive 1110 is also connected to the input / output (I / O) interface 1105 as needed. A removable medium 1111, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 1110 as needed, so that a computer program read therefrom is installed into the storage portion 1108 as needed.

[0207] The present disclosure also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiments; or may exist independently without being assembled into the device / apparatus / system. The above computer-readable storage medium carries one or more programs, and when the above one or more programs are executed, the method according to the embodiment of the present disclosure is implemented.

[0208] According to an embodiment of the present disclosure, a computer-readable storage medium may be a non-volatile computer-readable storage medium, for example, may include but is not limited to: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present disclosure, a computer-readable storage medium may be any tangible medium containing or storing a program, which may be used by or in combination with an instruction execution system, an apparatus, or a device. For example, according to an embodiment of the present disclosure, a computer-readable storage medium may include the ROM 1102 and / or RAM 1103 described above and / or one or more memories other than ROM 1102 and RAM 1103.

[0209] The embodiment of the present disclosure also includes a computer program product, which includes a computer program, and the computer program contains program code for executing the method shown in the flowchart. When the computer program product is run in a computer system, the program code is used to enable the computer system to implement the anti-deception interference imaging method of the synthetic aperture radar provided by the embodiment of the present disclosure.

[0210] The above functions defined in the system / device of the embodiment of the present disclosure are performed when the computer program is executed by the processor 1101. According to the embodiment of the present disclosure, the system, device, module, unit, etc. described above can be implemented by a computer program module.

[0211] In one embodiment, the computer program may rely on tangible storage media such as optical storage devices, magnetic storage devices, etc. In another embodiment, the computer program may also be transmitted and distributed in the form of signals on a network medium, and downloaded and installed through the communication part 1109, and / or installed from a removable medium 1111. The program code contained in the computer program may be transmitted using any appropriate network medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0212] In such an embodiment, the computer program can be downloaded and installed from the network through the communication part 1109, and / or installed from the removable medium 1111. When the computer program is executed by the processor 1101, the above functions defined in the system of the embodiment of the present disclosure are performed. According to the embodiment of the present disclosure, the system, device, means, module, unit, etc. described above can be implemented by a computer program module.

[0213] The flow charts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flow chart or block diagram can represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of a code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flow chart, and the combination of the boxes in the block diagram or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0214] It will be appreciated by those skilled in the art that the features described in the various embodiments of the present disclosure may be combined and / or combined in a variety of ways, even if such combinations or combinations are not explicitly described in the present disclosure. In particular, without departing from the spirit and teachings of the present disclosure, the features described in the various embodiments of the present disclosure may be combined and / or combined in a variety of ways. All of these combinations and / or combinations fall within the scope of the present disclosure.

[0215] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A synthetic aperture radar anti-deception interference imaging method, characterized in that: The method comprises: In response to a synthetic aperture radar anti-spoofing interference imaging request, obtaining the number of non-uniform pulse interval cycles; Determine a pulse interval period sequence according to a value range of the non-uniform pulse interval period and the number of the non-uniform pulse interval periods, wherein the value range of the non-uniform pulse interval period is determined according to the blind spot position of the synthetic aperture radar not being within an imaging area; Reconstructing the echo signal in azimuth to obtain a reconstructed signal with uniform sampling interval, wherein the echo signal represents a signal with non-uniform azimuth sampling interval that is reflected back to the synthetic aperture radar after encountering a target and the transmission signal sent by the synthetic aperture radar based on the pulse interval periodic sequence; Performing interference suppression on the reconstructed signal to obtain a target reconstructed signal; The target reconstructed signal is reconstructed in azimuth to obtain an image corresponding to the transmitted signal.

2. The method according to claim 1, characterized in that The echo signal includes an azimuth echo signal, the azimuth echo signal includes M channels, and the azimuth reconstruction of the echo signal to obtain a reconstructed signal with a uniform sampling interval includes: Determine the time domain signals of the M channels according to the azimuth echo signals; Performing Fourier transform on the time domain signals of the M channels to obtain frequency domain signals of the M channels; According to the frequency domain signals of the M channels, reconstructed signals with uniform sampling intervals are determined.

3. The method according to claim 2, characterized in that The step of determining, according to the frequency domain signals of the M channels, reconstructed signals with uniform sampling intervals for the M channels comprises: Determining a uniform echo matrix and a frequency domain weighting matrix of the M channels according to the frequency domain signals of each of the M channels; Obtaining a reconstruction matrix of the M channels according to the frequency domain weighting matrix and the number of pulse interval periods; Determining a spectrum matrix with uniform sampling intervals according to the reconstruction matrix, the uniform echo matrix, a preset uniform spectrum matrix and the frequency domain weighting matrix; The frequency spectrum matrix is ​​subjected to inverse Fourier transformation to obtain reconstructed signals with uniform sampling intervals for the M channels.

4. The method according to claim 3, characterized in that The performing interference suppression on the reconstructed signal to obtain a target reconstructed signal includes: Filtering the reconstructed signals of the M channels to obtain a first pulse compression result; The reconstructed signal of one of the M channels is set to zero in sequence and then filtered to obtain M second pulse compression results; Obtaining interference coefficients of the M channels according to the first pulse compression result and the M second pulse compression results; Determine an interference channel according to the interference coefficients of the M channels and a preset interference threshold; The target reconstructed signal is determined according to the reconstructed signal corresponding to the interference channel and the reconstructed signals of the M channels.

5. The method according to claim 4, characterized in that The determining the interference channel according to the interference coefficients of the M channels and a preset interference threshold comprises: Determining, according to the interference coefficients of the M channels and a preset interference coefficient, M coefficient differences between the interference coefficients of the M channels and the preset interference coefficient; The channels corresponding to the coefficient differences greater than 0 among the M coefficient differences are determined as interference channels.

6. The method according to claim 4, characterized in that The determining the target reconstructed signal according to the reconstructed signal corresponding to the interference channel and the reconstructed signals of the M channels includes: The reconstructed signal corresponding to the interference channel is removed from the reconstructed signals of the M channels to obtain the target reconstructed signal.

7. The method according to claim 1, characterized in that The step of reconstructing the target reconstructed signal in azimuth to obtain an image corresponding to the transmitted signal includes: constructing an azimuth imaging operator according to the target reconstructed signal and a preset azimuth inverse Fourier transform matrix; Constructing an azimuth imaging inverse operator according to the preset azimuth Fourier transform matrix, the preset initial imaging result, the preset azimuth matched filter matrix, and the preset azimuth inverse matched filter matrix; According to the azimuth imaging operator and the azimuth imaging inverse operator, the initial imaging result is iterated using a threshold iteration algorithm to obtain the image corresponding to the emission signal.

8. The method according to claim 7, characterized in that The step of iterating the initial imaging result by using a threshold iteration algorithm according to the azimuth imaging operator and the azimuth imaging inverse operator to obtain the image corresponding to the emission signal includes: Constructing a sparse signal model according to the azimuth imaging operator and the azimuth imaging inverse operator; According to the sparse signal model, the preset initial imaging result is iterated using a threshold iteration algorithm to obtain the image corresponding to the emission signal.

9. A synthetic aperture radar anti-deception interference imaging device, characterized in that: The device comprises: An acquisition module, used for acquiring the number of non-uniform pulse interval periods in response to an anti-deception interference imaging request of a synthetic aperture radar; A determination module, configured to determine a pulse interval period sequence according to a value range of the non-uniform pulse interval period and the number of the non-uniform pulse interval periods, wherein the value range of the non-uniform pulse interval period is determined according to the blind spot position of the synthetic aperture radar not being within an imaging area; The first obtaining module is used to reconstruct the echo signal in azimuth to obtain a reconstructed signal with uniform sampling interval, wherein the echo signal represents a signal with non-uniform azimuth sampling interval that is reflected back to the synthetic aperture radar after the transmission signal sent by the synthetic aperture radar based on the pulse interval period sequence encounters a target; A second obtaining module is used to perform interference suppression on the reconstructed signal to obtain a target reconstructed signal; The third obtaining module is used to reconstruct the target reconstructed signal in azimuth to obtain an image corresponding to the transmitted signal.

10. An electronic device, comprising: one or more processors; a memory for storing one or more computer programs, It is characterized in that the one or more processors execute the one or more computer programs to implement the steps of the method according to any one of claims 1 to 8.

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