An accurate calculation method, device and equipment for ISAR imaging corner turning

Abstract

The application provides an accurate calculation method, device and equipment for ISAR imaging rotation angle. The method comprises the following steps: obtaining first coordinate information of a target in a radar large earth coordinate system; converting the first coordinate information into a geocentric coordinate system to obtain third coordinate information; calculating a first included angle and a second included angle by using the third coordinate information in the geocentric coordinate system; and calculating the ISAR imaging rotation angle by using the first included angle and the second included angle. In the application, the spatial relationship among the geocenter, the ground-based radar and the target is coupled and calculated through the conversion among the coordinate systems, so that the correlation between the rotation angle value and the target orbit radius is generated, the limitations brought by the two-by-two spatial calculation model (radar-satellite, geocenter-satellite) of the traditional method are avoided, the accuracy of the imaging rotation angle calculation is improved, and finally the application efficiency of the ISAR technology in the medium-high orbit long-distance observation scene is improved.

Description

Technical Field

[0001] This invention relates to the field of radar signal processing technology, and specifically to a method, apparatus, and device for accurately calculating the ISAR imaging rotation angle. Background Technology

[0002] Inverse synthetic aperture radar (ISAR) imaging technology, as a key means in the field of high-resolution radar imaging, has wide application value in target characteristic analysis, space situational awareness, and other fields. Based on the range-Doppler (RD) principle, ISAR imaging acquires high resolution in the longitudinal range dimension of the target by transmitting a wide-bandwidth signal and constructs lateral resolution using the Doppler frequency shift caused by the relative rotation between the target and the radar. Its imaging quality is highly dependent on the accurate acquisition of the total rotation angle change between the target and the radar. However, in on-orbit observation scenarios, accurately calculating this rotation angle parameter still faces technical challenges.

[0003] In existing technologies, the mainstream approach to calculating the relative total rotation angle is estimation using an approximate geometric model. This model decomposes the target's rotation relative to the radar into functions of azimuth, elevation, and slant range variations. By measuring or estimating these parameters in real time and performing integration calculations using the orbital dynamics equations, an approximate value for the total rotation angle is obtained. This method offers a good balance between computational efficiency and accuracy requirements at lower orbital altitudes (such as low Earth orbit satellites or near-space platforms), making it a compromise solution in engineering applications.

[0004] However, the aforementioned approximate model has inherent flaws. Its derivation assumes that the nonlinear effect of the orbital radius on the rotational geometry is negligible. When the radar platform's orbital altitude increases (e.g., with medium- or high-orbit satellites or deep-space probes), the slant range between the target and the radar increases significantly, causing the deviation between the rotation angle output by the approximate model and the actual physical rotation angle to grow nonlinearly. This error not only causes inaccurate estimation of the lateral Doppler history but also introduces imaging plane projection distortion and phase compensation residuals. Ultimately, this manifests as a decrease in the focusing quality of the target's lateral range image and distortion of geometric features, severely limiting the application effectiveness of ISAR technology in medium- and high-orbit long-range observation scenarios. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides a method, apparatus, and device for accurately calculating the ISAR imaging rotation angle.

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

[0007] In a first aspect, the present invention provides a method for accurately calculating the rotation angle of ISAR imaging, comprising:

[0008] Obtain the target's first coordinate information in the radar's geodetic coordinate system;

[0009] The first coordinate information is transformed into the Earth-centered Earth-fixed coordinate system to obtain the third coordinate information;

[0010] In the geocentric-fixed coordinate system, the first included angle and the second included angle are calculated using the third coordinate information; the first included angle is the angle between the ground-based radar-target initial position and the geocentric-target initial position, and the second included angle is the angle between the ground-based radar-target final position and the geocentric-target final position;

[0011] The ISAR imaging rotation angle is calculated using the first included angle and the second included angle.

[0012] Optionally, the first coordinate information is transformed to the geocentric coordinate system to obtain the third coordinate information, including:

[0013] The first coordinate information is transformed into the radar's northeast-sky coordinate system to obtain the second coordinate information;

[0014] The second coordinate information is transformed into the Earth-centered Earth-fixed coordinate system to obtain the third coordinate information.

[0015] Optionally, in the geocentric coordinate system, the first and second included angles are calculated using third coordinate information, including:

[0016] In the geocentric-fixed coordinate system, the line-of-sight vector between the geocenter and the target is calculated using third coordinate information; the line-of-sight vector between the geocenter and the target includes: the line-of-sight vector at the initial position of the geocenter and the line-of-sight vector at the final position of the geocenter and the target.

[0017] The first and second included angles are calculated using the geocentric-target line-of-sight vector.

[0018] Alternatively, the first included angle is represented as:

[0019]

[0020] The second included angle is represented as:

[0021]

[0022] Where θ1 represents the first included angle, This represents the line-of-sight vector between ground-based radar A and the initial position P of the target. Let θ0 represent the line-of-sight vector from the Earth's center O to the target's initial position P, and θ2 represent the second included angle. This represents the line-of-sight vector between ground-based radar A and the final position P' of the target. This represents the line-of-sight vector between the Earth's center O and the target's final position P'.

[0023] Optionally, the ISAR imaging rotation angle is obtained using the first included angle and the second included angle, including:

[0024] The difference between the second included angle and the first included angle is used to obtain the ISAR imaging rotation angle.

[0025] Optionally, after obtaining the ISAR imaging rotation angle using the first and second included angles, the precise calculation method for the ISAR imaging rotation angle further includes:

[0026] By utilizing the ISAR imaging rotation angle and employing the PFA imaging algorithm, the target imaging calculation is performed to obtain the target's lateral range image.

[0027] Optionally, the line-of-sight vector between ground-based radar A and the initial target position P. Represented as:

[0028]

[0029] Line-of-sight vector between ground-based radar A and the final position P' of the target Represented as:

[0030]

[0031] Among them, (x p ,y p ,z p (x) represents the coordinates of the initial position P of the target in the Earth-centered, Earth-fixed coordinate system. p ,y p ,z p These represent the x-coordinate, y-coordinate, and vertical coordinates of the initial position P of the target in the Earth-centered, Earth-fixed coordinate system, respectively; (x A ,y A ,z A () represents the coordinates of ground-based radar A in the Earth-centered, Earth-fixed coordinate system, x A ,y A ,z A These represent the abscissa, ordinate, and vertical coordinates of ground-based radar A in the Earth-centered, Earth-fixed coordinate system, respectively; (x p' ,y p' ,z p' (x) represents the coordinates of the final position P' of the target in the Earth-centered, Earth-fixed coordinate system. p' ,y p' ,z p' These represent the x-coordinate, y-coordinate, and vertical coordinates corresponding to the final position P' of the target in the Earth-centered Earth-fixed coordinate system.

[0032] Secondly, the present invention provides a precise calculation device for ISAR imaging rotation angle, which includes: an acquisition unit, a coordinate transformation unit, and a calculation unit.

[0033] The acquisition unit is used to: acquire the target's first coordinate information in the radar's geodetic coordinate system;

[0034] The coordinate transformation unit is used to: transform the first coordinate information to the geocentric coordinate system to obtain the third coordinate information;

[0035] The calculation unit is used to: calculate the first included angle and the second included angle using the third coordinate information in the geocentric-ground-fixed coordinate system; the first included angle is the angle between the ground-based radar-target initial position and the geocentric-target initial position, and the second included angle is the angle between the ground-based radar-target final position and the geocentric-target final position;

[0036] The calculation unit is also used to calculate the ISAR imaging rotation angle using the first included angle and the second included angle.

[0037] Thirdly, the present invention provides a device for accurately calculating the ISAR imaging angle, comprising: a processor, a storage medium and a bus, wherein the storage medium stores machine-readable instructions executable by the processor, and when the device for accurately calculating the ISAR imaging angle is running, the processor communicates with the storage medium via the bus, and the processor executes the machine-readable instructions to perform the steps of the method for accurately calculating the ISAR imaging angle as described in the first aspect above.

[0038] This invention provides a method, apparatus, and device for accurately calculating ISAR imaging rotation angles. The method includes: acquiring the target's first coordinate information in the radar's geodetic coordinate system; transforming the first coordinate information to a geocentric-ground-fixed coordinate system to obtain third coordinate information; calculating a first included angle and a second included angle using the third coordinate information in the geocentric-ground-fixed coordinate system; the first included angle being the angle between the ground-based radar-target initial position and the geocentric-target initial position, and the second included angle being the angle between the ground-based radar-target final position and the geocentric-target final position; and calculating the ISAR imaging rotation angle using the first and second included angles. In this invention, the spatial relationship between the geocentric center, the ground-based radar, and the target is coupled and calculated through coordinate system transformation, creating a correlation between the rotation angle value and the target's orbital radius. This avoids the limitations of the pairwise spatial calculation models (radar-satellite, geocentric-satellite) of traditional methods, thereby improving the accuracy of imaging rotation angle calculation and ultimately enhancing the application efficiency of ISAR technology in medium- and high-orbit long-distance observation scenarios.

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0040] Figure 1 A flowchart illustrating a precise calculation method for ISAR imaging rotation angle provided in an embodiment of the present invention;

[0041] Figure 2 An exemplary schematic diagram of the ISAR imaging rotation calculation model is shown.

[0042] Figure 3 The imaging results after calculating the rotation compensation are illustrated in two exemplary models;

[0043] Figure 4 A schematic diagram of the structure of a precise calculation device for ISAR imaging rotation provided in an embodiment of the present invention;

[0044] Figure 5 This is a schematic diagram of the structure of an ISAR imaging rotation precision calculation device provided in an embodiment of the present invention. Detailed Implementation

[0045] In practical applications, the rotation angle changes with the target (satellite) orbital radius. However, existing rotation angle calculation models do not correlate the rotation angle value with the target (satellite) orbital radius, resulting in low accuracy. Furthermore, this invention couples the spatial relationships between the geocentric model, ground-based radar, and the satellite, establishing a correlation between the rotation angle value and the satellite orbital radius. This avoids the limitations of traditional pairwise spatial calculation models (radar-satellite or geocentric-satellite), thereby improving the accuracy of rotation angle calculation and enhancing the application effectiveness of ISAR technology in medium-to-high orbit long-distance observation scenarios.

[0046] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0047] To improve the application efficiency of ISAR technology in long-distance observation scenarios in medium and high orbits, this invention provides a method for accurately calculating the ISAR imaging rotation angle. Figure 1 A flowchart illustrating a precise calculation method for ISAR imaging rotation angle provided in an embodiment of the present invention is shown below. Figure 1 As shown, it includes:

[0048] S101. Obtain the first coordinate information of the target in the radar geodetic coordinate system.

[0049] S102. Transform the first coordinate information into the geocentric coordinate system to obtain the third coordinate information.

[0050] Optionally, S102 may specifically include:

[0051] The first coordinate information is transformed into the radar's northeast-sky coordinate system to obtain the second coordinate information;

[0052] The second coordinate information is transformed into the Earth-centered Earth-fixed coordinate system to obtain the third coordinate information.

[0053] Specifically, the second coordinate information can be represented as:

[0054]

[0055] Among them, (x g ,y g ,z g () represents the second coordinate information of the target in the radar's northeast-sky coordinate system, x g ,y g ,z g The corresponding coordinates represent the target's x, y, and y coordinates in the radar's northeast-sky coordinate system. (R, Az, E) are the target coordinates in the radar's geodetic coordinate system, i.e., the first coordinate information. R represents the distance from the center of the ground-based radar to the target, E represents the target's geodetic elevation angle relative to the origin in the radar's geodetic coordinate system, and Az represents the target's geodetic azimuth angle relative to the origin in the radar's geodetic coordinate system.

[0056] Taking the initial position of the target as an example, the target's third coordinate information can be represented as:

[0057]

[0058] Among them, (x p ,y p ,z p (x) represents the initial position coordinates of the target in the Earth-centered, Earth-fixed coordinate system. p ,y p ,z p The x, y, and z coordinates represent the initial position of the target in the geocentric coordinate system. B represents the latitude of the ground-based radar, L represents the longitude of the ground-based radar, and (x0, y0, z0) are the coordinates of the origin in the geocentric Cartesian coordinate system.

[0059] S103. Calculate the first and second included angles using the third coordinate information in the geocentric coordinate system.

[0060] The first included angle is the angle between the ground-based radar and the target's initial position and the Earth's center and the target's initial position, and the second included angle is the angle between the ground-based radar and the target's final position and the Earth's center and the target's final position.

[0061] Optionally, S103 may specifically include:

[0062] In the geocentric-fixed coordinate system, the line-of-sight vector between the geocenter and the target is calculated using third coordinate information; the line-of-sight vector between the geocenter and the target includes: the line-of-sight vector at the initial position of the geocenter and the line-of-sight vector at the final position of the geocenter and the target.

[0063] The first and second included angles are calculated using the geocentric-target line-of-sight vector.

[0064] Alternatively, the first included angle is represented as:

[0065]

[0066] The second included angle is represented as:

[0067]

[0068] Where θ1 represents the first included angle, This represents the line-of-sight vector between ground-based radar A and the initial position P of the target. Let θ0 represent the line-of-sight vector from the Earth's center O to the target's initial position P, and θ2 represent the second included angle. This represents the line-of-sight vector between ground-based radar A and the final position P' of the target. This represents the line-of-sight vector between the Earth's center O and the target's final position P'.

[0069] Figure 2 An exemplary schematic diagram of an ISAR imaging rotation calculation model is shown, which is applied to the ISAR imaging rotation calculation method. Figure 2 The ground-based radar (point A), the Earth's center (point O), and the target (points P and P') are transformed into the same coordinate system. The first angle θ1 is the angle between the initial position of the ground-based radar and the initial position of the Earth's center and the initial position of the target, and the second angle θ2 is the angle between the final position of the ground-based radar and the final position of the Earth's center and the final position of the target.

[0070] S104. The ISAR imaging rotation angle is calculated using the first included angle and the second included angle.

[0071] This invention provides a precise calculation method for ISAR imaging rotation angle. By transforming between coordinate systems, the spatial relationship between the geocentric model, ground-based radar, and target is coupled and calculated, so that the rotation angle value is correlated with the target orbital radius. This avoids the limitations of the pairwise spatial calculation models (radar-satellite, geocentric-satellite) of traditional methods, thereby improving the accuracy of rotation angle calculation and ultimately enhancing the application effectiveness of ISAR technology in medium and high orbit long-distance observation scenarios.

[0072] Optionally, S104 may specifically include:

[0073] The difference between the second included angle and the first included angle is used to obtain the ISAR imaging rotation angle.

[0074] Optionally, following S104, the precise calculation method for ISAR imaging rotation angle also includes:

[0075] By utilizing the ISAR imaging rotation angle and employing the PFA imaging algorithm, the target imaging calculation is performed to obtain the target's lateral range image.

[0076] Optionally, the line-of-sight vector between ground-based radar A and the initial target position P. Represented as:

[0077]

[0078] Line-of-sight vector between ground-based radar A and the final position P' of the target Represented as:

[0079]

[0080] Among them, (x p ,y p ,z p (x) represents the coordinates of the initial position P of the target in the Earth-centered, Earth-fixed coordinate system. p ,y p ,z p These represent the x-coordinate, y-coordinate, and vertical coordinates of the initial position P of the target in the Earth-centered, Earth-fixed coordinate system, respectively; (x A ,y A ,z A () represents the coordinates of ground-based radar A in the Earth-centered, Earth-fixed coordinate system, x A ,y A ,z A These represent the abscissa, ordinate, and vertical coordinates of ground-based radar A in the Earth-centered, Earth-fixed coordinate system, respectively; (x p' ,y p' ,z p' (x) represents the coordinates of the final position P' of the target in the Earth-centered, Earth-fixed coordinate system. p' ,y p' ,z p' These represent the x-coordinate, y-coordinate, and vertical coordinates corresponding to the final position P' of the target in the Earth-centered Earth-fixed coordinate system.

[0081] The method provided in this embodiment of the invention can be applied to electronic devices. Specifically, the electronic device can be a desktop computer, a portable computer, a smart mobile terminal, a server, etc., and this embodiment of the invention does not limit the application to such devices.

[0082] To verify the effectiveness of the method of the present invention, simulation experiments were also conducted.

[0083] Specifically, a comparative analysis was conducted between the comparative method and the method of this invention under different orbital radii. The comparative method refers to the relevant imaging rotation angle calculation method on pages 6-8 of "Bao Zheng, Xing Mengdao, Wang Tong. Radar Imaging Technology [M]. Beijing: Electronic Industry Press, 2005".

[0084] Artificial Earth satellite orbits can be classified into low Earth orbit, medium Earth orbit, and high Earth orbit according to their altitude above the ground. Generally, orbits with an altitude of 200 to 2,000 kilometers are called low Earth orbits, orbits with an altitude of 2,000 to 20,000 kilometers are called medium Earth orbits, and orbits above 20,000 kilometers are called high Earth orbits.

[0085] High orbit, medium orbit, and low orbit were selected, and the rotation angle calculation results of the two calculation models were obtained by following the comparison method and steps S101-S104 of the present invention, as shown in Table 1.

[0086] Table 1. Calculation results of rotation angle using two calculation models under different track radii.

[0087] Track type effective range Approximate model rotation angle Precise model rotation angle Angle difference High orbit ≈36000km 9.3160° 1.1050° 8.2110° medium orbit ≈3600km 9.3160° 5.8888° 3.4272° Low Earth Orbit ≈360km 9.3160° 8.5529° 0.7931°

[0088] As can be seen from Table 1, as the orbital radius increases, the rotation angle (approximate model rotation angle) obtained by the comparison method does not change with the orbital radius, while the rotation angle obtained by the rotation angle calculation method (precise model rotation angle) of the algorithm of this invention gradually decreases, and the difference between the two rotation angles gradually increases with the increase of altitude.

[0089] Furthermore, taking a high-orbit satellite as an example, the effectiveness of the ISAR imaging rotation angle calculation method (model) proposed in this invention was verified from the perspective of imaging results.

[0090] The parameters of the simulated ground-based radar system are shown in Table 2.

[0091] Table 2 Ground-based radar system parameter information

[0092] carrier frequency signal bandwidth Sampling rate Pulse width 10GHz 1GHz 1.2GHz 1μs PRF wavelength Central slope distance Scene width 1KHz 0.03m 36000km 30m

[0093] like Figure 3 The image shows the imaging results after calculating the rotation compensation under two different models. Figure 3 Figure (a) is a schematic diagram of the rotation compensation imaging results under the approximate model (comparison method). Figure 3 Figure (b) is a schematic diagram of the rotation compensation imaging results under the accurate model (method of the present invention), as shown below. Figure 3 As shown, Figure 3The target imaging result corresponding to Figure (a) has obvious shadows, while the target imaging result corresponding to the method of this invention has clear boundaries. Correspondingly, Table 3 shows the entropy values ​​of the angle compensation images calculated under the two models. As can be seen from Table 3, the entropy value of the angle compensation image under the approximate model (comparison method) is 6.6230, and the entropy value of the angle compensation image under the precise model (method of this invention) is 6.2212. Since the smaller the entropy value, the smaller the image clutter, it can be seen that the angle obtained by the ISAR imaging angle calculation model has a better imaging compensation effect, thus proving the effectiveness of the ISAR imaging angle calculation model proposed in this invention.

[0094] Table 3 shows the entropy values ​​of the angle compensation image calculated under the two models.

[0095] Image entropy value under approximate model with corner compensation Image entropy value under accurate model for corner compensation 6.6230 6.2212

[0096] Based on the same inventive concept, embodiments of the present invention also provide a device for accurately calculating the ISAR imaging rotation angle. Figure 4 This is a schematic diagram of a device for accurately calculating the rotation angle of ISAR imaging, provided in an embodiment of the present invention. Figure 4 As shown, it includes: an acquisition unit 401, a coordinate transformation unit 402, and a calculation unit 403;

[0097] The acquisition unit 401 is used to: acquire the first coordinate information of the target in the radar geodetic coordinate system;

[0098] The coordinate transformation unit 402 is used to: transform the first coordinate information to the geocentric coordinate system to obtain the third coordinate information;

[0099] The calculation unit 403 is used to: calculate the first included angle and the second included angle using the third coordinate information in the geocentric-ground-fixed coordinate system; the first included angle is the angle between the ground-based radar-target initial position and the geocentric-target initial position, and the second included angle is the angle between the ground-based radar-target final position and the geocentric-target final position;

[0100] The calculation unit 403 is also used to calculate the ISAR imaging rotation angle using the first included angle and the second included angle.

[0101] Figure 5 This is a schematic diagram of a precise calculation device for ISAR imaging angle provided in an embodiment of the present invention. The precise calculation device includes a processor 510, a storage medium 520, and a bus 530. The storage medium 520 stores machine-readable instructions executable by the processor 510. When the precise calculation device for ISAR imaging angle is running, the processor 510 communicates with the storage medium 520 via the bus 530. The processor 510 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 described in detail here.

[0102] The storage medium may include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. Optionally, the storage medium may also be at least one storage device located remotely from the aforementioned processor.

[0103] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0104] It should be noted that the terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders 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. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention.

[0105] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0106] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings and the disclosure, will understand and implement other variations of the disclosed embodiments in carrying out the claimed invention. In the description of the invention, the word "comprising" does not exclude other components or steps, "a" or "an" does not exclude a plurality, and "a plurality" means two or more, unless otherwise explicitly specified. Furthermore, while different embodiments may describe certain measures, this does not mean that these measures cannot be combined to produce good results.

[0107] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the inventive concept, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for accurately calculating the rotation angle of ISAR imaging, characterized in that, include: Obtain the target's first coordinate information in the radar's geodetic coordinate system; The first coordinate information is transformed into the Earth-centered Earth-fixed coordinate system to obtain the third coordinate information; In the geocentric-fixed coordinate system, the first included angle and the second included angle are calculated using the third coordinate information; the first included angle is the angle between the ground-based radar-target initial position and the geocentric-target initial position, and the second included angle is the angle between the ground-based radar-target final position and the geocentric-target final position; The ISAR imaging rotation angle is calculated using the first included angle and the second included angle; The calculation of the first included angle and the second included angle using the third coordinate information in the geocentric coordinate system includes: In the geocentric-fixed coordinate system, the line-of-sight vector of the geocentric target is calculated using the third coordinate information; the line-of-sight vector of the geocentric target includes: the line-of-sight vector of the initial position of the geocentric target and the line-of-sight vector of the final position of the geocentric target; The first included angle and the second included angle are calculated using the line-of-sight vector between the geocenter and the target. The first included angle is represented as: ； The second included angle is expressed as: ； in, Indicates the first included angle. Indicates ground-based radar - Initial target position The line-of-sight vector between them Represents the Earth's center To the initial position of the target The line-of-sight vector between them Indicates the second included angle. Indicates ground-based radar -Target final location The line-of-sight vector between them Represents the Earth's center To the final destination The line-of-sight vector between them.

2. The method for accurately calculating the ISAR imaging rotation angle according to claim 1, characterized in that, The step of transforming the first coordinate information to the Earth-centered Earth-fixed coordinate system to obtain the third coordinate information includes: The first coordinate information is transformed into the radar's northeast-sky coordinate system to obtain the second coordinate information; The second coordinate information is transformed into the Earth-centered Earth-fixed coordinate system to obtain the third coordinate information.

3. The method for accurately calculating the ISAR imaging rotation angle according to claim 1, characterized in that, The step of obtaining the ISAR imaging rotation angle using the first included angle and the second included angle includes: The difference between the second included angle and the first included angle is used to obtain the ISAR imaging rotation angle.

4. The method for accurately calculating the ISAR imaging rotation angle according to claim 1, characterized in that, After obtaining the ISAR imaging rotation angle using the first included angle and the second included angle, the precise calculation method for the ISAR imaging rotation angle further includes: Using the ISAR imaging rotation angle, the PFA imaging algorithm is employed to calculate the target imaging and obtain the target's lateral range image.

5. The method for accurately calculating the ISAR imaging rotation angle according to claim 1, characterized in that, The ground-based radar - Initial target position line-of-sight vectors Represented as: ； The ground-based radar -Target final location line-of-sight vectors Represented as: ； in, Indicates the initial position of the target in the Earth-centered and Earth-fixed coordinate system. The corresponding coordinate values, Representing the initial position of the target in the Earth-centered and Earth-fixed coordinate system respectively The corresponding x-coordinate, y-coordinate, and vertical coordinate; Represents ground-based radar in the Earth-centered and Earth-fixed coordinate system The corresponding coordinate values, Representing ground-based radar in the Earth-centered and Earth-fixed coordinate system The corresponding x-coordinate, y-coordinate, and vertical coordinate; Indicates the final position of the target in the Earth-centered and Earth-fixed coordinate system The corresponding coordinate values, Representing the final position of the target in the Earth-centered and Earth-fixed coordinate system respectively The corresponding x-coordinate, y-coordinate, and vertical coordinate.

6. A precise calculation device for ISAR imaging rotation angle, characterized in that, The precise calculation device for ISAR imaging rotation angle includes: an acquisition unit, a coordinate transformation unit, and a calculation unit; The acquisition unit is used to: acquire the first coordinate information of the target in the radar geodetic coordinate system; The coordinate transformation unit is used to: transform the first coordinate information to the geocentric coordinate system to obtain the third coordinate information; The calculation unit is used to: calculate a first included angle and a second included angle using the third coordinate information in the geocentric-ground-fixed coordinate system; the first included angle is the angle between the ground-based radar-target initial position and the geocentric-target initial position, and the second included angle is the angle between the ground-based radar-target final position and the geocentric-target final position; The calculation unit is also used to: calculate the ISAR imaging rotation angle using the first included angle and the second included angle; The calculation unit is specifically used to: calculate the line-of-sight vector of the geocenter-target using the third coordinate information in the geocenter-fixed coordinate system; the line-of-sight vector of the geocenter-target includes: the line-of-sight vector of the initial position of the geocenter-target and the line-of-sight vector of the final position of the geocenter-target; The first included angle and the second included angle are calculated using the line-of-sight vector between the geocenter and the target. The first included angle is represented as: ； The second included angle is expressed as: ； in, Indicates the first included angle. Indicates ground-based radar - Initial target position The line-of-sight vector between them Represents the Earth's center To the initial position of the target The line-of-sight vector between them Indicates the second included angle. Indicates ground-based radar -Target final location The line-of-sight vector between them Represents the Earth's center To the final destination The line-of-sight vector between them.

7. A device for accurately calculating the rotation angle of ISAR imaging, characterized in that, include: The device includes a processor, a storage medium, and a bus. The storage medium stores machine-readable instructions executable by the processor. When the device for accurately calculating the ISAR imaging angle is running, the processor communicates with the storage medium via the bus. The processor executes the machine-readable instructions to perform the steps of the method for accurately calculating the ISAR imaging angle as described in any one of claims 1-5.

Images