Echo modeling method and device of active millimeter wave focal plane system, equipment and medium

Abstract

The invention relates to an echo modeling method and device for an active millimeter wave focal plane system, equipment and a medium, and the method comprises the steps: constructing a geometric model of radar foresight imaging motion, obtaining target echo distance historical data at any moment based on the geometric model, and obtaining a target echo distance data model based on a Fourier optics theory; a multi-beam antenna pattern of the active millimeter wave focal plane imaging system is constructed, echo time delay information is obtained according to target echo distance historical data, a three-dimensional echo model is constructed according to the time delay information and the multi-beam antenna pattern, and a target echo signal of the active millimeter wave focal plane imaging system is generated based on the three-dimensional echo model. According to the method, the blank of coherent millimeter wave focal plane array three-dimensional imaging modeling is filled, a foundation is laid for research on design of a focal plane system and a three-dimensional imaging method, meanwhile, the method is simple and effective, complex focal plane field calculation is not needed, and the method is suitable for rapid radar echo signal simulation.

Description

Technical Field

[0001] The present application relates to the technical field of radar three-dimensional imaging echo modeling, and in particular to an echo modeling method, apparatus, device and medium for an active millimeter-wave focal plane system. Background Art

[0002] Millimeter-wave radar forward imaging can detect targets directly in front of a platform. It is widely used in complex terrain detection, aircraft landing, autonomous driving, and other fields, and is becoming a hot topic in radar research. Compared to two-dimensional range-azimuth forward imaging, three-dimensional forward imaging not only detects range but also simultaneously acquires two-dimensional azimuth-pitch angle information, thereby forming a three-dimensional reconstruction of the detected scene.

[0003] However, the coherent millimeter-wave focal plane imaging system is a hybrid analog / digital radar three-dimensional forward-looking imaging system with broad application prospects in fields such as terrain mapping, autonomous landing, and precision guidance. However, current research has largely focused on the development and prototype construction of focal plane arrays, and the lack of corresponding signal-level echo modeling and simulation tools has hindered system design and the research of focal plane array imaging algorithms. Summary of the Invention

[0004] Based on this, it is necessary to provide an echo modeling method, device, equipment and medium for an active millimeter-wave focal plane system that can simply and effectively simulate radar echo signals in order to solve the above technical problems.

[0005] An echo modeling method for an active millimeter wave focal plane system, the method comprising: Constructing a geometric model of radar forward imaging motion, and obtaining historical target echo distance data at any time based on the geometric model; Based on Fourier optics theory, a multi-beam antenna pattern for an active millimeter-wave focal plane imaging system is constructed; Echo delay information is obtained according to the target echo distance historical data, a three-dimensional echo model is constructed according to the delay information and the multi-beam antenna pattern, and a target echo signal of the active millimeter wave focal plane imaging system is generated based on the three-dimensional echo model.

[0006] In one embodiment, the geometric model is constructed based on the geometric position relationship and relative motion relationship between the target and the active millimeter wave focal plane imaging system.

[0007] In one embodiment, the target echo distance historical data is expressed as:

[0008] In the above formula, 、 、 They represent the slant range, azimuth angle and pitch angle of the target and the active millimeter wave focal plane imaging system at the initial moment, Indicates elapsed time After that, the distance that the active millimeter wave focal plane imaging system moves.

[0009] In one embodiment, constructing a multi-beam antenna pattern of an active millimeter-wave focal plane imaging system based on Fourier optics theory includes: Based on Fourier optics theory, a complex amplitude distribution signal representation on the focal plane field is obtained, and the focal plane field is approximated by an Airy disk function to simplify the complex amplitude distribution signal on the focal plane field to obtain a signal representation on the focal plane field; The signal representation on the focal plane field is projected from plane data to a spatial spherical coordinate system through a projection transformation operator to obtain the multi-beam antenna pattern.

[0010] In one embodiment, the multi-beam antenna pattern is expressed as:

[0011] In the above formula, Represents the spherical coordinate system Next The antenna directivity of the array element is and Respectively The azimuth and elevation deflection angles of each array element, represents the first-order Bessel function, represents the wave number, Indicates the radius of the parabola's mouth.

[0012] In one embodiment, obtaining the echo delay information according to the target echo distance historical data includes: A linear frequency modulation pulse signal is transmitted with the transmission signal of the active millimeter wave focal plane imaging system as the pulse repetition interval to construct an echo signal; Pulse compression and range migration correction are performed on the echo signal in the time domain to obtain a focal plane array intermediate frequency echo signal, namely the echo delay information.

[0013] In one embodiment, a three-dimensional echo model is constructed based on the time delay information and the multi-beam antenna pattern. The three-dimensional echo model is expressed as:

[0014] In the above formula, Indicates the focal plane The echo data received by each array element, represents the imaging detection airspace, represents the complex scattering coefficient of the target, Indicates the focal plane The directional pattern of the array element is at position The value of Indicates distance to fast time, Indicates the transmit pulse width, represents the rectangular window function, Indicates the carrier frequency, Indicates the frequency modulation slope of the linear frequency modulation signal.

[0015] The present application also provides an echo modeling device for an active millimeter wave focal plane system, the device comprising: A target echo distance historical data construction model is used to construct a geometric model of radar forward imaging motion, and based on the geometric model, the target echo distance historical data at any time is obtained; A multi-beam antenna pattern construction module, which is used to construct the multi-beam antenna pattern of the active millimeter-wave focal plane imaging system based on Fourier optics theory; A three-dimensional echo model construction module is used to obtain echo delay information based on the target echo distance historical data, construct a three-dimensional echo model based on the delay information and the multi-beam antenna radiation pattern, and generate the target echo signal of the active millimeter wave focal plane imaging system based on the three-dimensional echo model.

[0016] A computer device includes a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented: Constructing a geometric model of radar forward imaging motion, and obtaining historical target echo distance data at any time based on the geometric model; Based on Fourier optics theory, a multi-beam antenna pattern for an active millimeter-wave focal plane imaging system is constructed; Echo delay information is obtained according to the target echo distance historical data, a three-dimensional echo model is constructed according to the delay information and the multi-beam antenna pattern, and a target echo signal of the active millimeter wave focal plane imaging system is generated based on the three-dimensional echo model.

[0017] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the following steps: Constructing a geometric model of radar forward imaging motion, and obtaining historical target echo distance data at any time based on the geometric model; Based on Fourier optics theory, a multi-beam antenna pattern for an active millimeter-wave focal plane imaging system is constructed; Echo delay information is obtained according to the target echo distance historical data, a three-dimensional echo model is constructed according to the delay information and the multi-beam antenna pattern, and a target echo signal of the active millimeter wave focal plane imaging system is generated based on the three-dimensional echo model.

[0018] The echo modeling method, device, equipment and medium of the above-mentioned active millimeter-wave focal plane system construct a geometric model of the radar forward imaging motion, and obtain the historical data of the target echo distance at any time based on the modified geometric model. Based on Fourier optics theory, the multi-beam antenna radiation pattern of the active millimeter-wave focal plane imaging system is constructed, the echo time delay information is obtained according to the historical data of the target echo distance, and a three-dimensional echo model is constructed according to the time delay information and the multi-beam antenna radiation pattern. The target echo signal of the active millimeter-wave focal plane imaging system is generated based on the three-dimensional echo model. This method fills the gap in the three-dimensional imaging modeling of coherent millimeter-wave focal plane arrays and lays the foundation for the design of focal plane systems and the research of three-dimensional imaging methods. At the same time, this method is simple and effective, does not require complex focal plane field calculations, and is suitable for fast radar echo signal simulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 1 is a flow chart of an echo modeling method for an active millimeter-wave focal plane system according to an embodiment; Figure 2 A schematic diagram of the geometric relationship of three-dimensional forward-looking imaging of a radar in one embodiment; Figure 3 A schematic diagram of the spatial position of scattering points in an experiment; Figure 4 For an experiment Figure 3 Schematic diagram of the echo slice of the scattering point target simulated by this method; Figure 5 This is a SAR image of an extended target scene in an experiment; Figure 6 For an experiment Figure 5 Extended target echo slice view obtained by simulation using this method; Figure 7 is a structural block diagram of an echo modeling device of an active millimeter-wave focal plane system in one embodiment; Figure 8 FIG. 1 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0021] like Figure 1 As shown, an echo modeling method for an active millimeter wave focal plane system is provided, comprising the following steps: Step S100: constructing a geometric model of radar forward imaging motion, and obtaining historical data of target echo distance at any time based on the geometric model.

[0022] Step S110 : constructing a multi-beam antenna pattern of an active millimeter-wave focal plane imaging system based on Fourier optics theory.

[0023] Step S120 , obtaining echo delay information based on target echo distance history data, constructing a three-dimensional echo model based on the delay information and the multi-beam antenna pattern, and generating a target echo signal of the active millimeter wave focal plane imaging system based on the three-dimensional echo model.

[0024] In step S100, a geometric model is constructed based on the geometric position relationship and relative motion relationship between the target and the active millimeter wave focal plane imaging system.

[0025] In this embodiment, a radar motion geometric model is established in the North-Sky-East coordinate system, such as Figure 2 As shown. Assume that the platform (i.e., active millimeter wave focal plane imaging system) moves in a uniform linear motion in three-dimensional space with a speed of , the initial coordinates are (0, ,0), and the direction of movement is The angle in the positive direction of the axis is The position of any target within the radar beam range is P , the initial target P The slant range from the radar is , the azimuth angle is , the pitch angle is .

[0026] Further, over time After that, the platform movement distance is , assuming the target is stationary, then according to the cosine theorem, the slant range from the target to the radar platform (i.e., the active millimeter-wave focal plane imaging system) is It can be expressed as: (1) In formula (1), Indicates the pulse slowing time.

[0027] Then, in At , the second-order Taylor expansion of formula (1) is performed to obtain: (2) In formula (2), represents the linear distance traveled, represents the quadratic distance bending term, express About Time Since in the actual detection scene the platform movement speed and the square of the movement time Much smaller than the initial relative distance to the target , so the quadratic range bending term and the higher-order infinitesimal term can be ignored. Then formula (2) can be approximated as, that is, the target echo distance history data is expressed as: (3) In formula (3), 、 、 They represent the slant range, azimuth angle and pitch angle of the target and the active millimeter wave focal plane imaging system at the initial moment, Indicates elapsed time After that, the distance that the active millimeter wave focal plane imaging system moves.

[0028] In step S110, based on Fourier optics theory, a multi-beam antenna pattern of an active millimeter-wave focal plane imaging system is constructed, which includes two parts. First, based on Fourier optics theory, a complex amplitude distribution signal representation on the focal plane field is obtained, and the focal plane field is approximated by the Airy disk function. The complex amplitude distribution signal on the focal plane field is simplified to obtain a signal representation on the focal plane field. Then, through a projection transformation operator, the signal representation on the focal plane field is projected from plane data to a spatial spherical coordinate system to obtain a multi-beam antenna pattern.

[0029] In this embodiment, it is known from the Fourier optics principle that according to the linear nature of electromagnetic wave propagation, the complex amplitude distribution on the focal plane is It can be expressed as a superposition integral: (4) In formula (4), represents the complex amplitude distribution on the object surface, represents the impulse response of the system, i.e., the point spread function, Indicates that it is located The point source at The complex amplitude generated by the point.

[0030] Furthermore, the impulse response of the system is the Fraunhofer diffraction pattern of the parabola with a finite aperture, the center of which is the ideal image point in geometric optics. Position. The system impulse response function can be expressed as: (5) In formula (5), represents the circular aperture function, which is the finite aperture of the parabolic antenna and is defined as: (6) In formula (6), represents the radius of the parabola's mouth, Furthermore, after omitting the coefficient before the integral sign in formula (6), the system impulse response is the Fourier transform of the circular aperture function. For the parabolic antenna used in this system, the Fourier transform of the circular aperture function is the Airy disk pattern, which is expressed as: (7) In formula (7), represents the first-order Bessel function, represents the wave number, and , is the distance between the parabola's surface diameter plane and the focal plane, which is approximately equal to the focal length When the image point is located at the origin of the plane, that is, When , there are: (8) Furthermore, ignoring the space-varying characteristics of the point spread function of the system, the signal on the focal plane field is simplified to obtain the signal representation on the focal plane field, which can be expressed as: (9) Since the angle between the target scattering point and the platform changes constantly during the platform movement, it is necessary to consider the effect of the antenna directivity on the echo amplitude during the movement. The received data is projected onto the spherical surface Antenna directivity coefficient.

[0031] In this embodiment, the definition For flat data Antenna directivity coefficient in spherical coordinate system The projection transformation operator between , then: (10) (11) In formula (10) and formula (11), For the The antenna directivity of the array element is , Respectively Array elements in , The amount of focus in the direction, and Respectively The deflection angle of each array element in azimuth and elevation.

[0032] Therefore, by substituting formula (11) and formula (9) into formula (10), we can obtain The directional pattern of each element is the multi-beam antenna directional pattern, which is expressed as: (12) In formula (12), Represents the spherical coordinate system Next The antenna directivity of the array element is and Respectively The azimuth and elevation deflection angles of each array element, represents the first-order Bessel function, represents the wave number, Indicates the radius of the parabola's mouth.

[0033] In step S120, echo delay information is obtained based on the historical data of the target echo distance, including: transmitting a linear frequency modulated pulse signal with the transmission signal of the active millimeter wave focal plane imaging system as the pulse repetition interval, constructing an echo signal, performing pulse compression and range migration correction on the echo signal in the time domain, and obtaining a focal plane array intermediate frequency echo signal, that is, the echo delay information.

[0034] In this embodiment, the transmission signal of the active millimeter wave focal plane imaging system is modeled, assuming that the radar system is Transmits a linear frequency modulation (LFM) pulse signal for the pulse repetition interval , expressed as: (13) In formula (13), Indicates distance to fast time, Indicates the transmit pulse width, Indicates the carrier frequency, represents the frequency modulation slope of the linear frequency modulation signal, is a rectangular window function, expressed as: (14) Then, the focal plane array The point P received by the receiving element The echo signal for: (15) In formula (15), is the complex scattering coefficient of the target P. It is assumed here that the scattering coefficient of the same target is the same at all observation angles. The first The directional pattern of the receiving array element is The value of the position, It represents the echo delay of the target point P, and its expression is: ,in, for The slant range between the radar platform and the target at any moment.

[0035] Furthermore, for the above signal Pulse compression and range migration correction are performed in the time domain to obtain the focal plane array intermediate frequency echo signal. The echo signal received by each channel is demodulated using the I / Q channel orthogonal demodulation to remove the carrier signal, and then pulse compression is performed. The obtained echo signal expression is: (16) In formula (16), is the wavelength, is the signal bandwidth.

[0036] In order to eliminate the influence of platform movement on the echo signal, the above formula is corrected by distance movement, and the result is: (17) Then, substitute formula (3) into formula (18) to obtain: (18) In formula (18), the first phase term is a constant phase term, and the second phase term is the linear phase term caused by the Doppler frequency, and its Doppler frequency is expressed as: (19) Therefore, for the entire imaging detection space , the echo data received by each channel can be expressed as, that is, the three-dimensional echo model is expressed as: (20) In formula (20), Indicates the focal plane The echo data received by each array element, represents the imaging detection airspace, represents the complex scattering coefficient of the target, Indicates the focal plane The directional pattern of the array element is at position The value of Indicates distance to fast time, Indicates the transmit pulse width, represents the rectangular window function, Indicates the carrier frequency, Indicates the frequency modulation slope of the linear frequency modulation signal.

[0037] In this embodiment, the three-dimensional echo model represented by formula (20) can be used to simulate the target waveform for the active millimeter wave focal plane system.

[0038] In this embodiment, a standard Cassegrain antenna is used as a focal plane array imaging focusing antenna, and each step in the above method is further described in detail. Simulation experiments are performed on the constructed three-dimensional echo model to verify the effectiveness of this method.

[0039] First, according to step S100, the geometric position relationship and relative motion relationship between the target and the platform are established to obtain the echo distance history data. Then, based on formula (12) obtained in step S110, the parameters of the equivalent multi-beam antenna pattern are calculated according to the parabola parameters, and the antenna pattern model is constructed. Finally, the echo signal model is constructed by obtaining the delay information and antenna pattern information from the echo distance history. After pulse compression and migration correction in the distance dimension, the three-dimensional echo signal model is obtained using formula (20) obtained in step S120.

[0040] Next, in this paper, the effectiveness of this method is verified by simulating two scenarios: point target and extended target. The Cassegrain antenna parameter settings are shown in Table 1.

[0041] Table 1 Radar target parameter settings

[0042] First, the modeling results for the point target case are simulated. Four scattering points are constructed with the parameters shown in Table 2.

[0043] Table 2 Scattering point target parameter settings

[0044] It is distributed on different planes in the far field parallel to the aperture plane and is distributed in a "T" shape on the xy plane. The target distribution is shown in the attached figure. Figure 3 As shown in Figure 1, the initial distance between the platform and the target is 3000m. The echo data of each receiving channel obtained by this method are pulse compressed to obtain the millimeter wave image on each distance slice, as shown in the attached figure. Figure 4 As shown in the figure, the echo slices show that scattering point 2 appears in the slice at a distance of 2900m, while scattering points 1, 3, and 4 appear in the slice at a distance of 3000m. This is consistent with the relative distances of each scattering point from the platform. Furthermore, the positional relationships between the scattering points are consistent with the parameters set in the simulation, effectively verifying the correctness of the 3D imaging model for the scattering point target scenario.

[0045] Then change the simulation scene and select the SAR image data obtained by the Gaofen-3 satellite as the target scene for echo simulation. The original SAR image is as follows: Figure 5 As shown. The image size is 256×256 and the resolution is 3×3m, so the scene size corresponding to the image is 768×768m. The imaging scene is set as follows: the platform is located in the center of the scene, the height from the scene is 8000m, the radar bandwidth is 10MHz, and it works in a downward direction. The echo image obtained by this method is as follows Figure 6 As shown in the figure, the target scene is located on the range slice at a distance of 8000m from the platform. The relative positions of the two extended targets in the image formed by the imaging model are consistent with those in the original scene, verifying the effectiveness of the system imaging model for extended target imaging.

[0046] The above experiments prove that this method effectively realizes the three-dimensional imaging echo modeling of coherent millimeter-wave focal plane arrays. The simulation of ideal point targets and extended targets verifies the effectiveness and versatility of the echo model. This model is of great significance for the echo simulation modeling and imaging performance analysis of multi-beam antenna systems.

[0047] In the echo modeling method of the above-mentioned active millimeter-wave focal plane system, a geometric model of the radar forward imaging motion is constructed, and the historical data of the target echo distance at any time is obtained based on this geometric model. Based on Fourier optics theory, the multi-beam antenna radiation pattern of the active millimeter-wave focal plane imaging system is constructed, and the echo delay information is obtained according to the historical data of the target echo distance. A three-dimensional echo model is constructed based on the delay information and the multi-beam antenna radiation pattern. The target echo signal of the active millimeter-wave focal plane imaging system is generated based on the three-dimensional echo model. This method fills the gap in the three-dimensional imaging modeling of coherent millimeter-wave focal plane arrays and lays the foundation for the design of focal plane systems and the research of three-dimensional imaging methods. At the same time, this method is simple and effective, does not require complex focal plane field calculations, and is suitable for fast radar echo signal simulation.

[0048] It should be understood that although Figure 1 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. In addition, Figure 1 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0049] In one embodiment, Figure 7 As shown, an echo modeling device for an active millimeter wave focal plane system is provided, comprising: a target echo distance history data construction model 200, a multi-beam antenna pattern construction module 210, and a three-dimensional echo model construction module 220, wherein: The target echo distance history data construction model 200 is used to construct a geometric model of radar forward imaging motion, and based on the geometric model, obtain the target echo distance history data at any time; A multi-beam antenna pattern construction module 210 is used to construct a multi-beam antenna pattern of an active millimeter-wave focal plane imaging system based on Fourier optics theory; The three-dimensional echo model construction module 220 is used to obtain echo delay information based on the target echo distance historical data, construct a three-dimensional echo model based on the delay information and the multi-beam antenna radiation pattern, and generate the target echo signal of the active millimeter wave focal plane imaging system based on the three-dimensional echo model.

[0050] For the specific definition of the echo modeling device of the active millimeter wave focal plane system, please refer to the definition of the echo modeling method of the active millimeter wave focal plane system above, and will not be repeated here. The various modules in the echo modeling device of the active millimeter wave focal plane system can be implemented in whole or in part by software, hardware, or a combination thereof. The above modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0051] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Figure 8 As shown. The computer device includes a processor, a memory, a network interface, a display screen and an input device connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the computer device is used to communicate with an external terminal via a network connection. When the computer program is executed by the processor, an echo modeling method for an active millimeter wave focal plane system is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad provided on the computer device housing, or an external keyboard, touchpad or mouse.

[0052] Those skilled in the art will understand that Figure 8 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0053] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the following steps are implemented: Constructing a geometric model of radar forward imaging motion, and obtaining historical target echo distance data at any time based on the geometric model; Based on Fourier optics theory, a multi-beam antenna pattern for an active millimeter-wave focal plane imaging system is constructed; Echo delay information is obtained according to the target echo distance historical data, a three-dimensional echo model is constructed according to the delay information and the multi-beam antenna pattern, and a target echo signal of the active millimeter wave focal plane imaging system is generated based on the three-dimensional echo model.

[0054] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented: Constructing a geometric model of radar forward imaging motion, and obtaining historical target echo distance data at any time based on the geometric model; Based on Fourier optics theory, a multi-beam antenna pattern for an active millimeter-wave focal plane imaging system is constructed; Echo delay information is obtained according to the target echo distance historical data, a three-dimensional echo model is constructed according to the delay information and the multi-beam antenna pattern, and a target echo signal of the active millimeter wave focal plane imaging system is generated based on the three-dimensional echo model.

[0055] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), Synchronous Link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0056] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0057] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. An echo modeling method for an active millimeter wave focal plane system, characterized in that: The method comprises: Constructing a geometric model of radar forward imaging motion, and obtaining historical target echo distance data at any time based on the geometric model; Based on Fourier optics theory, the multi-beam antenna pattern of the active millimeter-wave focal plane imaging system is constructed; Echo delay information is obtained according to the target echo distance historical data, a three-dimensional echo model is constructed according to the delay information and the multi-beam antenna pattern, and a target echo signal of the active millimeter wave focal plane imaging system is generated based on the three-dimensional echo model.

2. The echo modeling method of the active millimeter wave focal plane system according to claim 1, characterized in that: The geometric model is constructed based on the geometric position relationship and relative motion relationship between the target and the active millimeter wave focal plane imaging system.

3. The echo modeling method of the active millimeter wave focal plane system according to claim 2, characterized in that: The target echo distance historical data is expressed as: In the above formula, 、 、 They represent the slant range, azimuth angle and pitch angle of the target and the active millimeter wave focal plane imaging system at the initial moment, Indicates elapsed time After that, the distance that the active millimeter wave focal plane imaging system moves.

4. The echo modeling method of the active millimeter wave focal plane system according to claim 3, characterized in that: The multi-beam antenna pattern of the active millimeter-wave focal plane imaging system is constructed based on Fourier optics theory, including: Based on Fourier optics theory, a complex amplitude distribution signal representation on the focal plane field is obtained, and the focal plane field is approximated by an Airy disk function to simplify the complex amplitude distribution signal on the focal plane field to obtain a signal representation on the focal plane field; The signal representation on the focal plane field is projected from plane data to a spatial spherical coordinate system through a projection transformation operator to obtain the multi-beam antenna pattern.

5. The echo modeling method of the active millimeter wave focal plane system according to claim 4, characterized in that: The multi-beam antenna pattern is expressed as: In the above formula, Represents the spherical coordinate system Next The antenna directivity of the array element is and Respectively The azimuth and elevation deflection angles of each array element, represents the first-order Bessel function, represents the wave number, Indicates the radius of the parabola's mouth.

6. The echo modeling method of the active millimeter wave focal plane system according to claim 5, characterized in that: The obtaining of echo delay information according to the target echo distance historical data includes: A linear frequency modulation pulse signal is transmitted with the transmission signal of the active millimeter wave focal plane imaging system as the pulse repetition interval to construct an echo signal; Pulse compression and range migration correction are performed on the echo signal in the time domain to obtain a focal plane array intermediate frequency echo signal, namely the echo delay information.

7. The echo modeling method of the active millimeter wave focal plane system according to claim 6, characterized in that: A three-dimensional echo model is constructed according to the time delay information and the multi-beam antenna pattern. The three-dimensional echo model is expressed as: In the above formula, Indicates the focal plane The echo data received by each array element, represents the imaging detection airspace, represents the complex scattering coefficient of the target, Indicates the focal plane The directional pattern of the array element is at position The value of Indicates distance to fast time, Indicates the transmit pulse width, represents the rectangular window function, Indicates the carrier frequency, Indicates the frequency modulation slope of the linear frequency modulation signal.

8. An echo modeling device for an active millimeter wave focal plane system, characterized in that: The device comprises: A target echo distance historical data construction model is used to construct a geometric model of radar forward imaging motion, and based on the geometric model, the target echo distance historical data at any time is obtained; A multi-beam antenna pattern construction module, which is used to construct the multi-beam antenna pattern of the active millimeter-wave focal plane imaging system based on Fourier optics theory; A three-dimensional echo model construction module is used to obtain echo delay information based on the target echo distance historical data, construct a three-dimensional echo model based on the delay information and the multi-beam antenna radiation pattern, and generate the target echo signal of the active millimeter wave focal plane imaging system based on the three-dimensional echo model.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

Images