Three-dimensional imaging method and device for interferometric inverse synthetic aperture radar in squint scenes

Abstract

The present invention provides a three-dimensional imaging method and device for interferometric inverse synthetic aperture radar (ISAR) in a squint scenario. The method comprises: performing pulse compression processing on echo signals acquired by a three-antenna system in a right-angle L configuration, and sequentially performing fast Fourier transform and HHO algorithm processing on the corresponding pulse compression echo data to obtain target motion parameters; constructing a dynamic virtual antenna based on the target motion parameters, pulse compression echo data, distance prior information, and angle prior information; performing squint compensation on the pulse compression echo data by calculating the dynamic baseline length and time-varying squint path difference of the dynamic virtual antenna to obtain compensated echo data for each antenna in the three-antenna system in the right-angle L configuration; performing translational motion compensation on the compensated echo data using the target motion parameters to obtain high-resolution ISAR images of the target for each antenna; and obtaining three-dimensional imaging results of the ISAR in the squint scenario from the high-resolution ISAR images.

Description

Technical Field

[0001] The present invention relates to the field of radar imaging technology, and in particular to a three-dimensional imaging method and device of an interferometric inverse synthetic aperture radar in a squint scene. Background Art

[0002] Radar three-dimensional imaging technology, a key development in the radar field, aims to overcome the limitations of inverse synthetic aperture radar (ISAR) in target recognition and enhance radar systems' target recognition and detection capabilities. Interferometric inverse synthetic aperture radar (InISAR) systems, based on the multi-antenna ISAR imaging principle, achieve three-dimensional reconstruction of targets through interferometric measurement. This technology is widely used in military reconnaissance, civilian surveillance, and other fields, and is of great significance for improving the overall performance of radar systems. Among them, the three-antenna InISAR configuration is highly favored due to its simple structure and small number of antennas. Under ideal conditions, when the target is located near the antenna's electrical axis (facing the scene directly), the projected coordinates estimated from different baselines are perpendicular to each other, enabling accurate reconstruction of the target's three-dimensional geometric structure.

[0003] However, in practical applications, due to the non-cooperative nature of the imaging target, the target is often in a squint scene far away from the antenna's electrical axis, which poses a severe challenge to existing InISAR imaging methods. To address the challenge of InISAR three-dimensional imaging in squint scenes, researchers have proposed a variety of solutions in recent years. Among them, the nonlinear least squares (NLS) method and the squint iterative improvement (SII) algorithm are two representative squint InISAR imaging solutions. Both methods are dedicated to eliminating the squint additional phase to accurately obtain the coordinate values ​​of the target scattering points along the baseline direction. Through coordinate transformation, the true coordinates of the target scattering points can be further obtained, thereby achieving three-dimensional imaging.

[0004] While the two aforementioned methods have achieved some success in InISAR imaging in squint scenarios, they still have some shortcomings. First, both methods primarily aim to eliminate the additive phase, requiring multiple iterations to complete the imaging process, resulting in low imaging efficiency. Second, the numerous approximations employed in these methods can introduce error propagation, impacting imaging accuracy. Therefore, achieving efficient and accurate InISAR 3D imaging in squint scenarios remains a pressing technical challenge in the field of radar imaging. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a three-dimensional imaging method and device for interferometric inverse synthetic aperture radar in a squint scene.

[0006] The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0007] In a first aspect, the present invention provides a three-dimensional imaging method for interferometric inverse synthetic aperture radar in a squint scene, which is applied to a right-angle L-configuration three-antenna system, comprising:

[0008] The echo signals obtained by the right-angle L-configuration three-antenna system are pulse compressed to obtain pulse compression echo data.

[0009] The pulse compression echo data is processed by fast Fourier transform, and the translation motion parameters are estimated based on the fast Fourier transform results and Harris Hawk optimized HHO algorithm to obtain the motion parameters of the target;

[0010] Construct a dynamic virtual antenna based on the target's motion parameters, pulse compression echo data, distance prior information, and angle prior information;

[0011] By calculating the dynamic baseline length and time-varying squint path difference of the dynamic virtual antenna, squint compensation is performed on the pulse compression echo data to obtain the compensated echo data of each antenna in the right-angle L-configuration three-antenna system.

[0012] The target's motion parameters are used to perform translational motion compensation on the compensated echo data to obtain high-resolution ISAR images of the target from each antenna.

[0013] The three-dimensional imaging results of interferometric inverse synthetic aperture radar in squint scenes are obtained based on high-resolution ISAR images.

[0014] Optionally, the right-angle L-configuration three-antenna system includes: a first antenna, a second antenna, and a third antenna;

[0015] The first antenna is a transceiver integrated antenna, the second antenna and the third antenna are both receiving antennas, and the first antenna is the coordinate origin of the right-angle L-configuration three-antenna system.

[0016] Optionally, the pulse compression echo data is subjected to fast Fourier transform processing, and translational motion parameters are estimated based on the fast Fourier transform processing result and the Harris Hawk optimized HHO algorithm to obtain the motion parameters of the target, including:

[0017] performing fast Fourier transform processing on the pulse compression echo data of the first antenna to obtain first echo transform data;

[0018] Perform polynomial modeling on the target's motion process to obtain the target scene model;

[0019] Based on the first echo transform data and the HHO algorithm under the target scene model, the translation motion parameters of the target are estimated to obtain the target motion parameters.

[0020] Optionally, the dynamic baseline length of the dynamic virtual antenna is expressed as:

[0021]

[0022] L X represents the dynamic baseline length, L1 represents the distance between the first antenna and the second antenna, θ X Indicates the angle between the target and the x-axis at the initial moment, R(t m ) represents the slow time moment t m The distance between the target rotation center and the first antenna when the target moves, wherein the dynamic baseline length represents the distance between the first antenna and the dynamic virtual antenna during the target movement;

[0023] The time-varying squint path difference of the dynamic virtual antenna is expressed as:

[0024]

[0025] BB″ represents a time-varying squint path difference, wherein the time-varying squint path difference represents the distance between the second antenna and the dynamic virtual antenna.

[0026] Optionally, by calculating the dynamic baseline length and time-varying squint path difference of the dynamic virtual antenna, squint compensation is performed on the pulse compression echo data to obtain compensated echo data of each antenna in the right-angle L-configuration three-antenna system, including:

[0027] Convolving the phase corresponding to the time-varying squint path difference with the pulse compression echo data of the second antenna and the third antenna, respectively, to obtain second compensated echo data and third compensated echo data after squint compensation;

[0028] The pulse compression echo data of the first antenna, the second compensation echo data and the third compensation echo data together constitute the compensation echo data of the right-angle L-configuration three-antenna system.

[0029] Optionally, a three-dimensional imaging result of an interferometric inverse synthetic aperture radar in a squint scene is obtained based on the high-resolution ISAR image, including:

[0030] The high-resolution ISAR images of all antennas are modulo-added to obtain a composite image;

[0031] Perform image registration on the high-resolution ISAR image according to the entropy of the synthetic image to obtain a high-resolution ISAR registered image;

[0032] The high-resolution ISAR registered images are interferometrically processed to obtain three-dimensional imaging results.

[0033] Optionally, performing image registration on the high-resolution ISAR image according to the entropy of the synthetic image to obtain a high-resolution ISAR registered image includes:

[0034] Image registration of high-resolution ISAR images using the HHO algorithm and synthetic images;

[0035] When the change in entropy of the synthetic image is less than a preset threshold, a high-resolution ISAR registration image is obtained.

[0036] In a second aspect, the present invention provides a three-dimensional imaging device for interferometric inverse synthetic aperture radar in a squint scene, which is applied to a right-angle L-configuration three-antenna system, comprising: a pulse compression unit, a parameter estimation unit, a virtual construction unit, a compensation unit, and an image generation unit;

[0037] The pulse compression unit is used to perform pulse compression processing on the echo signals obtained by the right-angle L-configuration three-antenna system to obtain pulse compression echo data;

[0038] The parameter estimation unit is used to perform fast Fourier transform processing on the pulse compression echo data, and perform translational motion parameter estimation based on the fast Fourier transform processing result and the Harris Hawk Optimization (HHO) algorithm to obtain the motion parameters of the target;

[0039] The virtual construction unit is used to construct a dynamic virtual antenna according to the target's motion parameters, pulse compression echo data, distance prior information, and angle prior information;

[0040] The compensation unit is used to perform squint compensation on the pulse compression echo data by calculating the dynamic baseline length and time-varying squint path difference of the dynamic virtual antenna, thereby obtaining compensated echo data for each antenna in the right-angle L-configuration three-antenna system. The compensated echo data is then subjected to translational motion compensation using the target's motion parameters, thereby obtaining a high-resolution ISAR image of the target from each antenna.

[0041] The image generation unit is used to obtain the three-dimensional imaging result of the interferometric inverse synthetic aperture radar in the squint scene based on the high-resolution ISAR image.

[0042] In a third aspect, the present invention provides a three-dimensional imaging device for interferometric inverse synthetic aperture radar in a squint scene, comprising: a processor, a storage medium and a bus, wherein the storage medium stores machine-readable instructions executable by the processor. When the three-dimensional imaging device for interferometric inverse synthetic aperture radar in a squint scene is running, the processor and the storage medium communicate via the bus, and the processor executes the machine-readable instructions to perform the steps of the three-dimensional imaging method for interferometric inverse synthetic aperture radar in a squint scene as described in the first aspect above.

[0043] The present invention provides a three-dimensional imaging method and device for interferometric inverse synthetic aperture radar (ISAR) in a squint scenario. The method comprises: performing pulse compression processing on echo signals acquired by a three-antenna system in a right-angle L configuration to obtain pulse compression echo data; performing fast Fourier transform processing on the pulse compression echo data, and estimating translational motion parameters based on the fast Fourier transform processing result and a Harris Hawk Optimization (HHO) algorithm to obtain target motion parameters; constructing a dynamic virtual antenna based on the target motion parameters, pulse compression echo data, distance prior information, and angle prior information; performing squint compensation on the pulse compression echo data by calculating the dynamic baseline length and time-varying squint path difference of the dynamic virtual antenna to obtain compensated echo data for each antenna in the three-antenna system in the right-angle L configuration; performing translational motion compensation on the compensated echo data using the target motion parameters to obtain high-resolution ISAR images of the target for each antenna; and obtaining a three-dimensional imaging result of the ISAR in the squint scenario based on the high-resolution ISAR images. In the present invention, by constructing a dynamic virtual antenna and calculating the time-varying squint path difference, InISAR three-dimensional imaging in squint scenes is achieved, thereby improving imaging quality. The HHO algorithm is used to estimate translational motion parameters, thereby improving the accuracy and stability of parameter estimation. Finally, through image registration technology, the high-resolution ISAR images of each antenna are fused, thereby improving the accuracy of the three-dimensional imaging results of the interferometric inverse synthetic aperture radar in squint scenes.

[0044] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A schematic flow chart of a three-dimensional imaging method using interferometric inverse synthetic aperture radar in a squint scenario provided by an embodiment of the present invention;

[0046] Figure 2 The schematic diagram of the structure of the target scene model is shown exemplarily;

[0047] Figure 3 The structural diagram of the ship scattering point model is shown as an example;

[0048] Figure 4 : This is an actual scenario diagram of an exemplary right-angle L-configuration three-antenna system;

[0049] Figure 5 The following example shows the three-dimensional imaging results of the interferometric inverse synthetic aperture radar at a squint angle of 30°.

[0050] Figure 6 The following example shows the three-dimensional imaging results of the interferometric inverse synthetic aperture radar at a 45° squint angle;

[0051] Figure 7 The following example shows the three-dimensional imaging results of the interferometric inverse synthetic aperture radar at a squint angle of 60°.

[0052] Figure 8 A schematic structural diagram of a three-dimensional imaging device for interferometric inverse synthetic aperture radar in a squint scenario provided by an embodiment of the present invention;

[0053] Figure 9 A schematic structural diagram of a three-dimensional imaging device for interferometric inverse synthetic aperture radar in a squint scenario provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0054] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0055] In order to improve the accuracy of three-dimensional imaging results of interferometric inverse synthetic aperture radar in a squint scene, an embodiment of the present invention provides a three-dimensional imaging method of interferometric inverse synthetic aperture radar in a squint scene. Figure 1 The present invention provides a flow chart of a three-dimensional imaging method of interferometric inverse synthetic aperture radar in a squint scene. Figure 1 As shown, including:

[0056] S101 , performing pulse compression processing on echo signals acquired by a right-angle L-configuration three-antenna system to obtain pulse compression echo data.

[0057] The right-angle L-configuration three-antenna system includes: a first antenna, a second antenna, and a third antenna;

[0058] The first antenna is a transceiver integrated antenna, the second antenna and the third antenna are both receiving antennas, and the first antenna is the coordinate origin of the right-angle L-configuration three-antenna system.

[0059] In the embodiment of the present invention, using the first antenna as the coordinate origin of the three-antenna system in a right-angle L configuration can facilitate system layout and calibration, as well as unify consistency and repeatability. This helps optimize system performance and improve the accuracy and real-time performance of signal processing.

[0060] S102 , performing fast Fourier transform processing on the pulse compression echo data, and performing translation motion parameter estimation based on the fast Fourier transform processing result and the Harris Hawk Optimization (HHO) algorithm to obtain the motion parameters of the target.

[0061] Optionally, S102 may specifically include:

[0062] performing fast Fourier transform processing on the pulse compression echo data of the first antenna to obtain first echo transform data;

[0063] Perform polynomial modeling on the target's motion process to obtain the target scene model;

[0064] Based on the first echo transform data and the HHO algorithm under the target scene model, the translation motion parameters of the target are estimated to obtain the target motion parameters.

[0065] It should be noted that since the first antenna acts as a transceiver, there is a direct correspondence between the signal it transmits and the echo signal it receives. This correspondence makes it more direct and accurate to extract the target's motion information from the echo data of the first antenna. In addition, in radar signal processing, simultaneously processing the echo data of multiple antennas may increase the computational complexity and time cost. Especially in application scenarios with high real-time requirements, this complexity may become a bottleneck for system performance. By processing only the echo data of the first antenna, the complexity of signal processing can be reduced while ensuring a certain level of accuracy, thereby improving the real-time performance and efficiency of the system. Finally, in a right-angle L-configuration three-antenna system, although each antenna may receive an echo signal from the target, these signals may contain redundant target motion information. By processing only the echo data of the first antenna and combining it with the HHO algorithm, sufficient target motion information can be extracted without the need to simultaneously process the echo data of multiple antennas.

[0066] In addition, the motion parameters of the target may include speed information and acceleration information of the target.

[0067] S103: Construct a dynamic virtual antenna according to the target's motion parameters, pulse compression echo data, distance prior information, and angle prior information.

[0068] Specifically, in this embodiment, a dynamic virtual antenna is constructed under a target scene model according to target motion parameters, pulse compression echo data, distance prior information, and angle prior information.

[0069] Figure 2 The schematic diagram of the target scene model is shown as an example. Figure 2 As shown, O-XYZ is the coordinate system of the right-angle L-configuration three-antenna system. The first antenna A (0, 0, 0) is located at the coordinate origin O, the second antenna B (L1, 0, 0) and the third antenna C (0, 0, L2) are located in the X-axis and Z-axis respectively, and L1 and L2 are the baseline lengths in the horizontal and vertical directions respectively. Specifically, L1 represents the distance between the first antenna and the second antenna, and L2 represents the distance between the first antenna and the third antenna. O' is the rotation center of the target, and the O'-UVW coordinate system is constructed with O' as the origin. During the radar observation time t0~t m (t0 is the initial time, t mIn the far field of the XOY plane (where the target is located at position 1 (the solid line target position O′ in the figure)), the target moves from position 1 (the solid line target position O′ in the figure) to position 2 (the dotted line target position O″ in the figure). Figure 2 In the figure, P is a scattering point inside the target, which moves from P′ to P″ following the target. Assume that during the movement, at the slow time t m At this moment, the coordinates of the scattering point P are (U P ,V P ,W P ), whose coordinates in the O-XYZ coordinate system are P(X P ,Y P ,Z P ).

[0070] Extend O′B and O″B so that they intersect the U′ axis at B′ and B″, respectively. Assume that a dynamic virtual antenna B′ exists within the U axis. As the target moves, the dynamic virtual antenna B′ also moves from B′ to B″. At this point, the L-shaped array formed by antennas AB′C will meet the far-field normal view condition when performing InISAR 3D imaging of the target. At this point, draw an auxiliary line BD′ perpendicular to AO′. The distance BD′ between the second antenna and the V axis and the distance AB′ between the first antenna and the virtual antenna at time t0 can be calculated:

[0071]

[0072] Among them, θ X represents the angle between the target and the x-axis at the initial moment, L1 represents the distance between the first antenna and the second antenna, and R0 represents the initial slant range of the target.

[0073] Since the coherent accumulation angle of ISAR imaging is relatively small (3° to 5°), in this embodiment, it can be approximately considered that at the slow time t m At this moment, the line AO″ connecting the first antenna and the target rotation center is perpendicular to the line AB″ connecting the first antenna and the virtual antenna, ∠D″AB≈θ X Furthermore, add an auxiliary line BD″ so that BD″ is perpendicular to AO″, and then we can get t m The length of the distance BD″ between the second antenna and the V axis and the distance AB″ between the first antenna and the virtual antenna at time:

[0074]

[0075] R(t m ) represents the slow time moment t m The dynamic baseline length represents the distance between the first antenna and the dynamic virtual antenna during the target movement.

[0076] S104 , performing squint compensation on the pulse compression echo data by calculating the dynamic baseline length and the time-varying squint path difference of the dynamic virtual antenna, and obtaining compensated echo data of each antenna in the right-angle L-configuration three-antenna system.

[0077] In the above formula, R(t m )=R0+ΔR(t m ), when t=t0, there is R(t m )=R0. Combining the above formula, the dynamic baseline length L along the U′ axis is X Can be expressed as L X .

[0078] Optionally, the dynamic baseline length of the dynamic virtual antenna is expressed as:

[0079]

[0080] L X represents the dynamic baseline length, L1 represents the distance between the first antenna and the second antenna, θ X Indicates the angle between the target and the x-axis at the initial moment, R(t m ) represents the slow time moment t m The distance between the target rotation center and the first antenna when the target moves, wherein the dynamic baseline length represents the distance between the first antenna and the dynamic virtual antenna during the target movement;

[0081] The time-varying squint path difference of the dynamic virtual antenna is expressed as:

[0082]

[0083] BB″ represents a time-varying squint path difference, wherein the time-varying squint path difference represents the distance between the second antenna and the dynamic virtual antenna.

[0084] In summary, the overall process is: obtain the distance prior information R0 and angle prior information θ through the traditional right-angle L-configuration three-antenna system X Then, we can get the target motion parameters by combining the target motion parameters with the distance prior information R0 to get R(t m ). Finally, calculate the dynamic baseline length L X Then through L X Calculate the time-varying squint path difference BB″. Taking antenna pair AB as an example, squint compensation can be completed by compensating the phase corresponding to the time-varying squint path difference BB″ in the echo data of antenna B.

[0085] Optionally, S104 may specifically include:

[0086] Convolving the phase corresponding to the time-varying squint path difference with the pulse compression echo data of the second antenna and the third antenna, respectively, to obtain second compensated echo data and third compensated echo data after squint compensation;

[0087] The pulse compression echo data of the first antenna, the second compensation echo data and the third compensation echo data together constitute the compensation echo data of the right-angle L-configuration three-antenna system.

[0088] S105 , performing translational motion compensation on the compensated echo data using the target's motion parameters, to obtain a high-resolution ISAR image of the target from each antenna.

[0089] For example, the echo of the first antenna after translational motion compensation, that is, the high-resolution ISAR image of the first antenna with respect to the target, can be expressed as:

[0090]

[0091] Represents the estimated value of the target-based motion parameters when the first antenna is at the hth range-frequency unit and the kth slow time The obtained echo after translation motion compensation, M represents the total number of pulses, N represents the total number of range units, m represents the mth slow time, n represents the range frequency unit, -N / 2≤n≤N / 2-1, 0≤m≤M-1; j represents the imaginary unit, S A (n; m) represents the total echo signal of the first antenna about the target, c represents the transmission speed of the echo, Δf r Represents the distance frequency, f c Indicates the carrier frequency, represents the coefficient of the lth order term, L represents the total number of orders, Δt m represents the slow time sampling interval, Represents the estimated values ​​of the motion parameters of the target.

[0092] The echo of the second antenna after translational motion compensation, that is, the high-resolution ISAR image of the second antenna about the target can be expressed as:

[0093]

[0094] represents the echo of the second antenna after translational motion compensation, σ PB represents the backscattering coefficient of the scattering point P with respect to the second antenna, σ PA represents the backscattering coefficient of the scattering point P with respect to the first antenna, represents the ideal ISAR echo signal of the first antenna, R B,WPD (·) represents the time-varying path difference of strabismus that needs to be compensated.

[0095] Adaptively, the echo of the third antenna after translational motion compensation can correspond to Based on the above, adaptive replacement is performed, that is, the parameters of the second antenna are replaced with the parameters of the third antenna.

[0096] S106. Obtain three-dimensional imaging results of interferometric inverse synthetic aperture radar in a squint scene based on the high-resolution ISAR image.

[0097] Specifically, in the above-mentioned interferometric processing, it is necessary to first extract strong scattering points of the high-resolution ISAR registered image, and then perform interferometric processing on the high-resolution ISAR registered image based on the strong scattering points. The extraction of strong scattering points can be performed based on a peak extraction algorithm.

[0098] In this embodiment of the present invention, the three-dimensional imaging result before rotation can be expressed as:

[0099]

[0100] Among them, U P represents the coordinate of the scattering point P on the U′ axis, V P represents the coordinate of the scattering point P on the V′ axis, W P represents the coordinate of the scattering point P on the W′ axis, It represents the phase obtained by interfering the echo of the virtual antenna with the echo of the first antenna, R0 represents the initial slant range, and n P Indicates the distance unit number of the scattering point P, -N / 2≤n P ≤N / 2-1, f s represents the fast-time sampling frequency, represents the phase obtained by interference between the echo of the first antenna and the echo of the third antenna, and L2 represents the distance between the first antenna and the third antenna.

[0101] Furthermore, after obtaining the three-dimensional imaging result before rotation, it is also necessary to convert U P 、V P and W P The scattering point coordinate matrix is ​​rotated by θ X After obtaining the angle prior information, the three-dimensional imaging result of the interferometric inverse synthetic aperture radar in the squint scene is finally obtained.

[0102] An embodiment of the present invention provides a three-dimensional imaging method for an interferometric inverse synthetic aperture radar (ISAR) in a squint scenario, comprising: performing pulse compression processing on echo signals obtained by a three-antenna system in a right-angle L configuration to obtain pulse compression echo data; performing fast Fourier transform processing on the pulse compression echo data, and estimating translational motion parameters based on the result of the fast Fourier transform processing and a Harris Hawk Optimization (HHO) algorithm to obtain motion parameters of the target; constructing a dynamic virtual antenna according to the motion parameters of the target, the pulse compression echo data, distance prior information, and angle prior information; performing squint compensation on the pulse compression echo data by calculating the dynamic baseline length and time-varying squint path difference of the dynamic virtual antenna to obtain compensated echo data of each antenna in the three-antenna system in the right-angle L configuration; performing translational motion compensation on the compensated echo data using the motion parameters of the target to obtain a high-resolution ISAR image of the target for each antenna; and obtaining a three-dimensional imaging result of the ISAR in the squint scenario based on the high-resolution ISAR image. In an embodiment of the present invention, by constructing a dynamic virtual antenna and calculating the time-varying squint path difference, InISAR three-dimensional imaging in squint scenarios is achieved, thereby improving imaging quality. The HHO algorithm is used to estimate translational motion parameters, thereby improving the accuracy and stability of parameter estimation. Finally, through image registration technology, the high-resolution ISAR images of each antenna are fused, thereby improving the accuracy of the three-dimensional imaging results of the interferometric inverse synthetic aperture radar in squint scenarios.

[0103] Optionally, S106 may specifically include:

[0104] The high-resolution ISAR images of all antennas are modulo-added to obtain a composite image;

[0105] Perform image registration on the high-resolution ISAR image according to the entropy of the synthetic image to obtain a high-resolution ISAR registered image;

[0106] The high-resolution ISAR registered images are interferometrically processed to obtain the three-dimensional imaging results of interferometric inverse synthetic aperture radar in the squint scene.

[0107] It should be noted that, during the interferometric processing, it is necessary to first extract the strong scattering points of the high-resolution ISAR registered image, and then perform interferometric processing on the high-resolution ISAR registered image based on the strong scattering points to obtain a three-dimensional imaging result.

[0108] Optionally, performing image registration on the high-resolution ISAR image according to the entropy of the synthetic image to obtain a high-resolution ISAR registered image includes:

[0109] Image registration of high-resolution ISAR images using the HHO algorithm and synthetic images;

[0110] When the change in entropy of the synthetic image is less than a preset threshold, a high-resolution ISAR registration image is obtained.

[0111] In order to verify the effectiveness of the three-dimensional imaging method of interferometric inverse synthetic aperture radar in a squint scene provided by an embodiment of the present invention, a simulation experiment was also conducted. The following is a simulation experiment:

[0112] The ship scattering point model is constructed using the publicly available length, width and height data of a destroyer. Figure 3 .like Figure 3 As shown in Figure 1, the model contains 51 scattering points with a size of 155m×120.4m×33.3m. Assume that the scattering coefficient of each scattering point in the model is 1. Figure 2 and Figure 4 The main simulation parameters of the right-angle L-configuration three-antenna InISAR system are shown in Table 1. The experimental operation system is an Intel(R) Core(TM) i5-13400F@2.50GHz and an NVIDIA GeForceRTX 4060GPU, with a 64-bit Windows 10 operating system, and the simulation software is MATLAB, version R2024a.

[0113] Table 1 Main simulation parameters of InISAR system

[0114] parameter Numerical parameter Numerical <![CDATA[Baseline L1]]> 4m <![CDATA[Baseline L2]]> 4m carrier frequency 10GHz bandwidth 200MHz PRF 400Hz Target distance 30km Pulse Width 2us Sampling frequency 240MHz Number of distance units 960 Number of orientation units 512

[0115] Implementation steps: Set the initial squint angle of the ship target to 30°, and the translation speed, acceleration and movement direction of the ship target to: 20m / s, 5m / s2, 45°. Figure 4 The figure shows an actual scenario of a right-angle L-configuration three-antenna system. Figure 4 The antenna A, antenna B and antenna C correspond to the first antenna, the second antenna and the third antenna respectively. The above-mentioned squint angle is the angle formed by the line formed by the target rotation center and the first antenna and the X-axis, and the movement direction is the angle between the target speed direction and the X-axis. At the same time, in order to simulate the yaw motion of the target, the rotation speed of the three-dimensional model around the Z-axis is set to 0.1rad / s. In order to verify the effectiveness and robustness of the proposed method, additive complex Gaussian white noise is added to the echo of each antenna so that the signal-to-noise ratio of the signal is 10dB. Finally, after processing based on the method of the present invention, the three-dimensional imaging results of the interferometric inverse synthetic aperture radar in the squint scene are shown in the attached figure. Figure 5-7 shown. Specifically, Figure 5 The following diagram shows the 3D imaging results of the interferometric inverse synthetic aperture radar at a 30° squint angle. Figure 6 The following example shows the 3D imaging results of the interferometric inverse synthetic aperture radar at a 45° squint angle. Figure 7 The following example shows the three-dimensional imaging results of the interferometric inverse synthetic aperture radar at a squint angle of 60°. Figure 5 , Figure 5 The image on the left in the middle represents a three-dimensional view of the three-dimensional imaging result, and the results on the right are, from top to bottom, the range-azimuth profile, the height-range profile, and the height-azimuth profile of the left image. Figure 5 Result represents the 3D imaging result, i.e., the 3D coordinates of the scattering points reconstructed using the method of the present invention. Model represents the actual 3D coordinates of the scattering points in the model. The blue X, Y, and Z characters indicate the 3D coordinates of the reconstructed scattering points obtained using the method of the present invention, as indicated by the blue arrows and the *. The red X, Y, and Z characters indicate the 3D coordinates of the scattering points in the actual model, as indicated by the red arrows and the circles. Figure 6 and Figure 7 and Figure 5 The corresponding elements in are interpreted the same way. Figure 5-Figure 7 It can be seen that the reconstructed three-dimensional imaging result obtained based on the method of the present invention is highly consistent with the real model with a small deviation, which verifies that the method of the present invention has high imaging accuracy.

[0116] In order to quantitatively describe the performance of the method of the present invention, the root mean square error (RMSE) between the reconstructed scattering point coordinates and the ideal three-dimensional geometric model is used as a quantitative indicator.

[0117] Table 2 gives Figure 5-7 The RMSE between the imaging results and the model is shown in Table 3. Furthermore, the present invention also conducted experiments at different signal-to-noise ratios (20, 15, and 10 dB) and different squint angles (30°, 45°, and 60°), with one additional repeat for each. The RMSE between the imaging results and the model is also reported in Table 3.

[0118] Table 2 RMSE between the 3D imaging results and the model at different squint angles and SNRs in the first group of experiments

[0119]

[0120]

[0121] Table 3 RMSE between 3D imaging results and the model at different squint angles and SNRs in repeated experiments

[0122]

[0123] comprehensive Figure 5-7 From the data in Tables 2 and 3, it can be concluded that the method of the present invention exhibits superior imaging performance at different squint angles and different signal-to-noise ratios. At the same time, the method of the present invention is less affected by noise and has strong robustness.

[0124] In summary, the improvements of the method of the present invention are:

[0125] 1. The method of the present invention innovatively proposes a method for constructing a dynamic virtual antenna. By constructing a dynamic virtual antenna, the imaging perspective of the antenna system is transformed, the residual squint time-varying path difference is visualized and targeted compensation is performed.

[0126] 2. This method innovatively applies the Harris Hawk (HHO) algorithm to radar imaging. Using the entropy of two-dimensional ISAR images and synthetic images as criteria, this algorithm achieves translational motion compensation and image registration parameter estimation, ultimately enabling high-resolution ISAR imaging and ISAR image registration of targets. Based on the registered ISAR images, this method ultimately realizes three-dimensional InISAR imaging in squint scenarios.

[0127] The method provided in the embodiment of the present invention can be applied to electronic devices. Specifically, the electronic devices can be desktop computers, portable computers, smart mobile terminals, servers, etc., which are not limited in the embodiment of the present invention.

[0128] Based on the same inventive concept, an embodiment of the present invention further provides a three-dimensional imaging device for interferometric inverse synthetic aperture radar in a squint scene. Figure 8 The present invention provides a schematic diagram of the structure of a three-dimensional imaging device of an interferometric inverse synthetic aperture radar in a squint scene. Figure 8 As shown, it includes: a pulse compression unit 801, a parameter estimation unit 802, a virtual construction unit 803, a compensation unit 804 and an image generation unit 805;

[0129] The pulse compression unit 801 is used to perform pulse compression processing on the echo signals obtained by the right-angle L-configuration three-antenna system to obtain pulse compression echo data;

[0130] The parameter estimation unit 802 is used to perform fast Fourier transform processing on the pulse compression echo data, and perform translation motion parameter estimation based on the fast Fourier transform processing result and the Harris Hawk Optimization (HHO) algorithm to obtain the motion parameters of the target;

[0131] The virtual construction unit 803 is used to construct a dynamic virtual antenna according to the target's motion parameters, pulse compression echo data, distance prior information, and angle prior information;

[0132] The compensation unit 804 is configured to: perform squint compensation on the pulse compression echo data by calculating the dynamic baseline length and time-varying squint path difference of the dynamic virtual antenna, thereby obtaining compensated echo data for each antenna in the right-angle L-configuration three-antenna system; and perform translational motion compensation on the compensated echo data using the target's motion parameters, thereby obtaining a high-resolution ISAR image of the target for each antenna.

[0133] The image generation unit 805 is used to obtain a three-dimensional imaging result of an interferometric inverse synthetic aperture radar in a squint scene based on the high-resolution ISAR image.

[0134] Figure 9 A schematic structural diagram of a 3D imaging device for interferometric inverse synthetic aperture radar (ISAR) in squint scenarios provided by an embodiment of the present invention includes a processor 910, a storage medium 920, and a bus 930. The storage medium 920 stores machine-readable instructions executable by the processor 910. When the 3D imaging device for interferometric inverse synthetic aperture radar in squint scenarios operates, the processor 910 communicates with the storage medium 920 via the bus 930, and the processor 910 executes the machine-readable instructions to perform the steps of the above-described method embodiment. The specific implementation and technical effects are similar and will not be further described here.

[0135] The storage medium may include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage. Alternatively, the storage medium may be at least one storage device located away from the processor.

[0136] The above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, and discrete hardware components.

[0137] It should be noted that the terms "first," "second," and the like are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in sequences other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the present invention.

[0138] In the description of this specification, the reference terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" mean that the specific features or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0139] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art can understand and implement other variations of the above-mentioned disclosed embodiments by viewing the drawings and the disclosed content. In the description of the present invention, the word "comprising" does not exclude other components or steps, "one" or "an" does not exclude multiple situations, and the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. In addition, certain measures are recorded in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

[0140] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. For those skilled in the art of the present invention, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the scope of protection of the present invention.

Claims

1. A three-dimensional imaging method for interferometric inverse synthetic aperture radar in a squint scene, applied to a right-angle L-configuration three-antenna system, characterized in that: include: performing pulse compression processing on the echo signals acquired by the right-angle L-configuration three-antenna system to obtain pulse compression echo data; Performing fast Fourier transform processing on the pulse compression echo data, and performing translation motion parameter estimation based on the result of the fast Fourier transform processing and the Harris Hawk optimized HHO algorithm to obtain the motion parameters of the target; constructing a dynamic virtual antenna according to the motion parameters of the target, the pulse compression echo data, the distance prior information, and the angle prior information; By calculating the dynamic baseline length and time-varying squint path difference of the dynamic virtual antenna, squint compensation is performed on the pulse compression echo data to obtain compensated echo data of each antenna in the right-angle L-configuration three-antenna system; Performing translational motion compensation on the compensated echo data using the motion parameters of the target to obtain a high-resolution ISAR image of the target from each antenna; Based on the high-resolution ISAR image, a three-dimensional imaging result of interferometric inverse synthetic aperture radar in a squint scene is obtained.

2. The 3D imaging method of interferometric inverse synthetic aperture radar in a squint scene according to claim 1, characterized in that: The right-angle L-configuration three-antenna system includes: a first antenna, a second antenna, and a third antenna; The first antenna is a transceiver integrated antenna, the second antenna and the third antenna are both receiving antennas, and the first antenna is the coordinate origin of the right-angle L-configuration three-antenna system.

3. The 3D imaging method of interferometric inverse synthetic aperture radar in a squint scene according to claim 2, characterized in that: The pulse compression echo data is subjected to fast Fourier transform processing, and translational motion parameter estimation is performed based on the result of the fast Fourier transform processing and the Harris Hawk optimized HHO algorithm to obtain the motion parameters of the target, including: Performing fast Fourier transform processing on the pulse compression echo data of the first antenna to obtain first echo transform data; Perform polynomial modeling on the target's motion process to obtain the target scene model; Based on the first echo transform data and the HHO algorithm under the target scene model, translation motion parameters of the target are estimated to obtain motion parameters of the target.

4. The 3D imaging method of interferometric inverse synthetic aperture radar in a squint scene according to claim 2, characterized in that: The dynamic baseline length of the dynamic virtual antenna is expressed as: L X represents the dynamic baseline length, L1 represents the distance between the first antenna and the second antenna, θ X Indicates the angle between the target and the x-axis at the initial moment, R(t m ) represents the slow time moment t m The distance between the target rotation center and the first antenna when the target moves, wherein the dynamic baseline length represents the distance between the first antenna and the dynamic virtual antenna during the target movement; The time-varying squint path difference of the dynamic virtual antenna is expressed as: BB″ represents a time-varying squint path difference, wherein the time-varying squint path difference represents the distance between the second antenna and the dynamic virtual antenna.

5. The 3D imaging method of interferometric inverse synthetic aperture radar in a squint scene according to claim 2, characterized in that: The method of calculating the dynamic baseline length and the time-varying squint path difference of the dynamic virtual antenna to perform squint compensation on the pulse compression echo data to obtain compensated echo data of each antenna in the right-angle L-configuration three-antenna system includes: Convolving the phase corresponding to the time-varying squint path difference with the pulse compression echo data of the second antenna and the third antenna, respectively, to obtain second compensated echo data and third compensated echo data after squint compensation; The pulse compression echo data of the first antenna, the second compensation echo data and the third compensation echo data together constitute the compensation echo data of the right-angle L-configuration three-antenna system.

6. The 3D imaging method of interferometric inverse synthetic aperture radar in a squint scene according to claim 1, characterized in that: The method of obtaining a three-dimensional imaging result of an interferometric inverse synthetic aperture radar in a squint scene based on the high-resolution ISAR image includes: The high-resolution ISAR images of all antennas are modulo-added to obtain a composite image; Performing image registration on the high-resolution ISAR image according to the entropy of the synthetic image to obtain a high-resolution ISAR registered image; Interference processing is performed on the high-resolution ISAR registered image to obtain the three-dimensional imaging result.

7. The 3D imaging method of interferometric inverse synthetic aperture radar in a squint scene according to claim 6, characterized in that: The performing image registration on the high-resolution ISAR image according to the entropy of the synthetic image to obtain a high-resolution ISAR registered image includes: performing image registration on the high-resolution ISAR image using the HHO algorithm and the synthetic image; When the change in entropy of the synthetic image is less than a preset threshold, the high-resolution ISAR registration image is obtained.

8. A three-dimensional imaging device for interferometric inverse synthetic aperture radar in a squint scene, applied to a right-angle L-configuration three-antenna system, characterized in that: It includes: a pulse compression unit, a parameter estimation unit, a virtual construction unit, a compensation unit and an image generation unit; The pulse compression unit is used to perform pulse compression processing on the echo signals obtained by the right-angle L-configuration three-antenna system to obtain pulse compression echo data; The parameter estimation unit is used to: perform fast Fourier transform processing on the pulse compression echo data, and perform translation motion parameter estimation based on the result of the fast Fourier transform processing and the Harris Hawk Optimization HHO algorithm to obtain the motion parameters of the target; The virtual construction unit is used to: construct a dynamic virtual antenna according to the motion parameters of the target, the pulse compression echo data, the distance prior information and the angle prior information; The compensation unit is configured to: perform squint compensation on the pulse compression echo data by calculating the dynamic baseline length and the time-varying squint path difference of the dynamic virtual antenna to obtain compensated echo data of each antenna in the right-angle L-configuration three-antenna system; perform translational motion compensation on the compensated echo data using the motion parameters of the target to obtain a high-resolution ISAR image of the target for each antenna; The image generation unit is used to obtain a three-dimensional imaging result of an interferometric inverse synthetic aperture radar in a squint scene based on the high-resolution ISAR image.

9. A three-dimensional imaging device for interferometric inverse synthetic aperture radar in a squint scene, characterized in that: include: A processor, a storage medium, and a bus, wherein the storage medium stores machine-readable instructions executable by the processor. When the three-dimensional imaging device for interferometric inverse synthetic aperture radar in a squint scene is operated, the processor and the storage medium communicate via the bus, and the processor executes the machine-readable instructions to perform the steps of the three-dimensional imaging method for interferometric inverse synthetic aperture radar in a squint scene as described in any one of claims 1 to 7.

Images