A radar system and a method for target detection using a radar system.

Abstract

This application provides a radar system and a target detection method. The radar system provided includes a beam transmission control component, a polarization angle modulator, an antenna array with adjustable linear polarization, a signal receiving and processing unit, and a computer. The beam transmission control component generates a transmitted signal. The polarization angle modulator modulates the transmitted signal according to the beam polarization angle indicated by the computer. The computer determines the beam polarization angle for each modulation cycle, and based on the beam polarization angle corresponding to each modulation cycle and the processing information corresponding to that modulation cycle, determines the polarization response characteristics of the target, and detects the target based on the target polarization response characteristics during target detection and tracking. The radar system and target detection method provided in this application can improve the signal-to-noise ratio, identification capability, and anti-interference ability of the radar system for detecting small, slow-moving targets.

Description

Technical Field

[0001] This application relates to the field of radar technology, and more particularly to a radar system and a method for target detection using a radar system. Background Technology

[0002] In the field of low-altitude safety three-dimensional perception, small, slow-moving targets are difficult to detect, track, and identify due to their low flight altitude, slow speed, small radar cross-section, and strong near-ground clutter interference. Existing detection technologies mainly employ high-resolution X-band or Ku-band pulse Doppler radar systems to detect, track, and identify these targets. While using shorter wavelength signals can improve radar resolution, the rapid attenuation of high-frequency signals in the low-altitude atmosphere limits the effective detection range of the radar system. This is especially true for small or micro-UAV targets made of composite materials, whose radar cross-section is far less than 0.01 m². Traditional radar systems struggle to obtain effective radar echo signals in the complex electromagnetic environment of low altitudes, severely limiting their detection capabilities. Existing radar detection technologies are insufficient to meet the requirements of low-altitude safety three-dimensional perception systems for the rapid detection, tracking, and identification of small, slow-moving targets. Summary of the Invention

[0003] In view of this, this application provides a radar system and a method for target detection using the radar system, so as to improve the radar system's detection range, feature recognition capability, and anti-jamming capability for small, slow targets.

[0004] Specifically, this application is implemented through the following technical solution:

[0005] The first aspect of this application provides a radar system, which includes a beam transmission control component, a polarization angle modulator, an antenna array with adjustable linear polarization direction, a signal receiving and processing unit, and a computer;

[0006] The beam transmission control component is used to generate a transmission signal according to the waveform and beam position direction indicated by the computer.

[0007] The polarization angle modulator is used to modulate the transmitted signal according to the beam linear polarization angle indicated by the computer, so that the linear polarization angle of the modulated radar beam signal changes dynamically; the polarization angle modulator has a modulation range of 0° to 180°, covering the entire polarization surface.

[0008] The antenna array is used to transmit the radar beam signal and receive the echo signal of the radar beam signal.

[0009] The signal receiving and processing unit is used to receive the echo signal, process the echo signal, and send the processing information to the computer.

[0010] The computer is used to dynamically determine the beamline polarization angle of each modulation period according to a preset detection and search strategy; the modulation period is equal to an integer multiple of the coherent processing interval of the radar system, the beamline polarization angle corresponding to each modulation period remains unchanged, and the beamline polarization angle in different modulation periods changes dynamically according to the detection and search strategy.

[0011] The computer is also used to determine the polarization response characteristics of the target based on the beamline polarization angle corresponding to each modulation period and the processing information corresponding to that modulation period.

[0012] The computer is also used to detect the target based on the target polarization response characteristics during target detection and tracking.

[0013] A second aspect of this application provides a method for target detection using a radar system, the method comprising:

[0014] The beamline polarization angle of each modulation cycle is dynamically determined according to a preset detection and search strategy; the modulation cycle is equal to an integer multiple of the coherent processing interval of the radar system, the beamline polarization angle corresponding to each modulation cycle remains unchanged, and the beamline polarization angle in different modulation cycles changes dynamically according to the detection and search strategy.

[0015] Based on the beamline polarization angle corresponding to each modulation period and the processing information corresponding to that modulation period, the polarization response characteristics of the target are determined.

[0016] During the detection and tracking of the target after its discovery, the target is detected based on the target polarization response characteristics.

[0017] The radar system and target detection method provided in this application, by controlling the beamline polarization angle modulator, can modulate the polarization direction of the transmitted beam according to the beamline polarization angle indicated by the computer. The modulation range is from 0° to 180°. In this way, the radar system can control the polarization angle of the transmitted beam and make the beamline polarization angle cover the entire polarization surface. Thus, when detecting low, small, and slow targets, the radar system can dynamically adjust the polarization angle of the radar beam to match the polarization characteristics of the target, thereby enhancing the echo signal strength, improving the signal-to-noise ratio, and anti-interference capability. In addition, by performing polarization scanning on the target, the radar system can fully detect the polarization response characteristics of the target, improving the target feature recognition capability. Furthermore, after detecting the target polarization response characteristics, the radar system can dynamically detect and track the target's polarization response characteristics, analyze the real-time spatial attitude changes of the target, and optimize the dynamic detection and tracking strategy for the target. In summary, the radar system provided in this embodiment enhances the radar echo signal strength, improves the signal-to-noise ratio and anti-interference capability, enhances the target feature recognition capability, detects and analyzes the target's spatial attitude in real time, and optimizes the target detection and tracking strategy by adapting to the target's polarization characteristics. This significantly improves the radar system's ability to detect small, slow targets. Attached Figure Description

[0018] Figure 1 A schematic diagram of a radar system embodiment 1 provided in this application;

[0019] Figure 2 This is a schematic diagram illustrating the change in beamline polarization angle as shown in an exemplary embodiment of this application;

[0020] Figure 3 This is a schematic diagram illustrating the change in beamline polarization angle, as shown in another exemplary embodiment of this application.

[0021] Figure 4 This is a flowchart of an embodiment of the method for target detection using a radar system provided in this application. Detailed Implementation

[0022] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.

[0023] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used herein are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0024] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0025] Analysis of the physical structure of small, slow-moving targets and verification experiments revealed that both multi-rotor and fixed-wing UAVs have a large number of wire bundles and metal ribs arranged in their rotor arms or fuselage, which have obvious polarization characteristics in response to radar beam illumination. This characteristic can be used for target detection and tracking. Furthermore, due to structural differences, different models of UAVs show significantly different polarization response characteristics to radar beam illumination. Therefore, target identification and real-time spatial attitude analysis can be performed by analyzing the polarization response characteristics of the target echo.

[0026] This application provides a radar system and a method for target detection using the radar system, in order to improve the radar system's detection range, feature recognition capability, and anti-jamming capability for small, slow-moving targets.

[0027] The following specific embodiments are given to illustrate the technical solution of this application in detail.

[0028] Figure 1 This is a schematic diagram of a radar system embodiment one provided in this application. Please refer to... Figure 1 The radar system provided in this embodiment includes a beam transmission control component, a polarization angle modulator, an antenna array with adjustable linear polarization direction, a signal receiving and processing unit, and a computer.

[0029] The beam transmission control component is used to generate a transmission signal according to the waveform and beam position direction indicated by the computer.

[0030] The polarization angle modulator is used to modulate the transmitted signal according to the beam linear polarization angle indicated by the computer, so that the linear polarization angle of the modulated radar beam signal changes dynamically; the polarization angle modulator has a modulation range of 0° to 180°, covering the entire polarization surface.

[0031] The antenna array is used to transmit the radar beam signal and receive the echo signal of the radar beam signal.

[0032] The signal receiving and processing unit is used to receive the echo signal, process the echo signal, and send the processing information to the computer.

[0033] The computer is used to dynamically determine the beamline polarization angle of each modulation period according to a preset detection and search strategy; the modulation period is equal to an integer multiple of the coherent processing interval of the radar system, the beamline polarization angle corresponding to each modulation period remains unchanged, and the beamline polarization angle in different modulation periods changes dynamically according to the detection and search strategy.

[0034] The computer is also used to determine the polarization response characteristics of the target based on the beamline polarization angle corresponding to each modulation period and the processing information corresponding to that modulation period.

[0035] The computer is also used to detect the target based on the target polarization response characteristics during target detection and tracking.

[0036] Specifically, the beam transmission control component may include a transmitter component and a beam pointing controller. The transmitter component and the beam pointing controller are used to generate a transmission signal according to the waveform and beam pointing indicated by the computer, and to control the waveform of the radar beam signal and the beam pointing when scanning and detecting the target airspace.

[0037] Specifically, the computer is used for resource management, data processing, and logical flow control of the entire radar system. Specifically, it dynamically determines the spatial beam position of the detection beam according to a preset detection and search strategy, while simultaneously dynamically determining the modulation period and beam polarization angle of the beamline. The modulation period (also called the beamline polarization angle modulation period) is equal to an integer multiple of the coherent processing interval of the radar system. The beamline polarization angle remains constant within each modulation period, while the beamline polarization angle dynamically changes according to the polarization detection strategy within different modulation periods.

[0038] The computer is also used to analyze and determine whether a target has been detected based on the beamline polarization angle, echo signal intensity, echo characteristics, and set signal-to-noise ratio threshold for each modulation period, analyze the polarization response characteristics of the target, and identify the target based on the polarization response characteristics and other signal characteristics.

[0039] The computer is also used to perform target detection and tracking, real-time spatial attitude analysis, hazard assessment, and safety warning based on the target polarization response characteristics and detection and tracking strategy during the detection and tracking process after the target is detected.

[0040] Specifically, the transmitter assembly and beam pointing controller are used to generate the transmitted signal based on the waveform and beam pointing indicated by the computer. The signal waveform (e.g., a linear frequency modulated pulse) is generated by the transmitter assembly, while the beam pointing is dynamically determined by the computer based on the executed target airspace detection strategy. The beam pointing is dynamically controlled by the beam pointing controller, which controls the phase difference between the transmitted signals transmitted to each antenna element in the antenna array. The computer-controlled radar system's task logic flow involves selecting the transmitted signal waveform, controlling the transmitted signal sequence, and dynamically arranging the beam position of the transmitted signal sequence in the detection airspace. The beam position corresponds to the beam pointing of the signal sequence, ensuring that the radar beam can cover the target airspace. The arranged beam position of the transmitted signal sequence forms the basis for subsequent polarization angle modulation; beamline polarization angle modulation modulates the polarization angle of the beam of the arranged beam position transmitted signal sequence.

[0041] Specifically, beamline polarization angle modulation (BPA) modulates the beamline polarization angle of the transmitted signal according to the beamline polarization angle determined by the detection and search strategy executed by the computer, so that the beamline polarization angle of the modulated radar beam signal changes dynamically. After the computer instructs a specific beamline polarization angle, the beamline polarization angle modulator controls the transmitted signal energy allocated to the horizontal and vertical polarization elements of the linearly polarized antenna array based on that angle value, thereby controlling the oscillation direction of the electromagnetic waves transmitted by the linearly polarized antenna array elements, so that the polarization direction of the transmitted beam is consistent with the beamline polarization angle instructing by the computer. By adjusting the energy ratio of the linearly polarized electromagnetic wave in the vertical and horizontal directions in the polarization plane, the deflection of the beamline polarization angle is achieved, thereby giving the beam sequence the required polarization direction. For example, when the horizontal direction of the specified beam polarization plane is 0° and assuming that the performance and electromagnetic radiation pattern structure of the horizontal and vertical polarization elements of the antenna array are completely identical, if the energy allocated to the horizontal and vertical polarization elements of the antenna array is the same, the polarization angle of the transmitted beam of the antenna array is 45°; if the energy allocated to the horizontal and vertical polarization elements makes the ratio of the field strength of the transmitted beam of the horizontal and vertical polarization elements 1:1.732, the polarization angle of the transmitted beam of the antenna array is 60°.

[0042] Furthermore, the polarization-adjustable antenna array undertakes the dual tasks of transmitting and receiving signals. It can not only transmit the polarization-modulated beam sequence according to the wave positions arranged by the radar detection strategy to conduct polarization detection in the target airspace, but also receive echo signals for coherent detection and polarization feature detection.

[0043] Specifically, during the detection and search phase, the computer dynamically determines the beamline polarization angle for each modulation cycle according to the detection and search strategy being executed.

[0044] It should be noted that the detection and search phase is the stage of beam scanning and searching the target airspace during the detection process. It is mainly used to comprehensively understand the target airspace situation and detect the presence, distribution, and number of targets. The polarization response characteristics of a target refer to the differences in the echo signals generated by the target under illumination by linearly polarized radar beams with different polarization directions. Since the electromagnetic wave scattering characteristics of targets with different materials and physical structures are closely related to the polarization direction of the illuminating beam, the echo signals will exhibit significant differences in intensity, phase, and polarization characteristics when a target is illuminated by radar beams with different polarization directions. For example, for a regular-shaped target made of metal, when its main reflector is aligned with the polarization direction of the illuminating beam, the incident electromagnetic wave is more likely to generate electromagnetic oscillations within the target, resulting in the strongest echo signal. However, when its main reflector is perpendicular to the polarization direction of the illuminating beam, the electromagnetic oscillation efficiency generated by the incident electromagnetic wave within the target is the lowest, and the echo signal strength is significantly weakened. Using beams modulated by linear polarization angles to detect targets can significantly improve radar signal-to-noise ratio and anti-jamming performance. For example, in small multi-rotor UAVs made of composite materials, because wire bundles are evenly distributed throughout all rotor structures, strong echo signals may be generated from beams with different linear polarization directions, exhibiting multiple local peaks, i.e., multi-peak polarization response characteristics. This multi-peak response characteristic reflects the polarization response features of the target under beam illumination with different polarization directions. By detecting and identifying the polarization response characteristics of the target, it can be used to analyze and identify target types or structural features, thereby improving the accuracy and reliability of target identification.

[0045] It should be noted that in this embodiment, the modulation period is an integer multiple of the coherent processing interval of the radar system. For ease of explanation, the coherent processing interval is denoted as CPI, and the modulation period is nCPI, where n is an integer greater than or equal to 1. For example, the modulation period can be CPI, 3CPI, etc. In this embodiment, it is not limited and is determined by the polarization detection strategy used in actual use. Furthermore, the coherent processing interval refers to the continuous time length or pulse sequence duration used by the radar system for coherent signal processing.

[0046] It is understandable that a coherent processing interval contains multiple linear frequency modulated pulses.

[0047] It should be noted that the beamline polarization angle remains constant within each modulation period, but changes dynamically between different modulation periods, achieving polarization detection according to the detection search strategy. For example, the beamline polarization angle is 45° in the first modulation period and 46° in the second modulation period.

[0048] Understandably, setting the modulation period to an integer multiple of the coherent processing interval offers significant advantages in system coordination and signal processing. This setting ensures that at least one complete coherent accumulation process is completed at each fixed beamline polarization angle, resulting in an echo signal with good coherence and temporal stability, which is beneficial for subsequent Doppler processing, target detection, and polarization feature extraction.

[0049] Furthermore, aligning the modulation period with the coherent processing interval simplifies the radar system control logic and avoids introducing problems such as coherent accumulation breaks or blurred processing boundaries during polarization angle modulation, thereby improving the overall signal processing efficiency and detection accuracy of the radar system. In actual detection, this design ensures that the data blocks corresponding to each polarization angle are continuous, complete, and comparable, providing a reliable data foundation for subsequent accurate analysis of polarization response characteristics and polarization angle optimization.

[0050] It should be noted that, in one possible implementation, the moduloable range of the beamline polarization angle covers the range required by the beam polarization detection strategy. This allows the radar system to perform more comprehensive polarization detection of the target airspace from multiple angles and with different polarization characteristics, thereby improving radar detection capabilities and performance.

[0051] In practical implementation, Figure 2 This is a schematic diagram illustrating the change in beamline polarization angle, as shown in an exemplary embodiment of this application. (Refer to...) Figure 2 , Figure 2 In the rectangle, one modulation period is represented. Figure 2 In the example shown, the beamline polarization angle of each modulation cycle is dynamically determined according to the preset detection search strategy. Any angle between 0° and 180° can be selected as the beamline polarization angle of the initial modulation cycle. In each subsequent modulation cycle, the beamline polarization angle increases periodically according to the increment set by the detection search strategy until it covers the polarization detection range specified by the detection search strategy.

[0052] It should be noted that the increment step size is set according to actual needs. In this embodiment, it is not limited. For example, it can be 1°, or even 10°. The following explanation uses 10° as an example. In the modulation range of 0° to 180°, the beamline polarization angle of the first modulation cycle is 0°, the beamline polarization angle of the second modulation cycle is 10°, the beamline polarization angle of the third modulation cycle is 20°, and so on, until it reaches 180°, completing one scan of the polarization plane.

[0053] Figure 3 This is a schematic diagram illustrating the change in beamline polarization angle, as shown in another exemplary embodiment of this application. (Refer to...) Figure 3 In one possible implementation, the beamline polarization angle of each modulation cycle is dynamically determined according to a preset detection and search strategy.

[0054] Reference Figure 3 It should be noted that, Figure 3 One rectangle in the diagram represents one modulation cycle. Loading Figure 3 In the example shown, any angle between 0° and 180° can be selected as the beamline polarization angle of the initial modulation period. In each subsequent modulation period, the beamline polarization angle decreases periodically according to the set decreasing step size until it covers the search range specified by the polarization detection search strategy.

[0055] It should be noted that the set reduction step size is determined according to actual needs, and is not limited in this embodiment. Furthermore, the set reduction step size can be fixed, or different reduction step sizes can be used in different modulation periods. For example, when the set reduction step size is fixed, the reduction step size can be 1° or 10°.

[0056] The following example uses a fixed decreasing step size of 10°. In this example, the beamline polarization angle of the first modulation cycle is 180°, the beamline polarization angle of the second modulation cycle is 170°, the beamline polarization angle of the third modulation cycle is 160°, and so on, until the beamline polarization angle reaches 0°, completing one scan of the polarization plane.

[0057] Understandably, the method described above, which determines the beamline polarization angle for each modulation cycle using a fixed step size for incremental or decremental adjustments, offers advantages such as simple system structure, easy implementation of control logic, and comprehensive coverage of the entire polarization surface. This method can uniformly sample the polarization angle across the entire beamline polarization angle modulation range, ensuring that the radar system can fully acquire the echo signals of the target under illumination by different linearly polarized beams, and can be used to dynamically construct the target's polarization response characteristic curve. Furthermore, the linearly increasing or decreasing angle setting logic is clear and easy to implement, facilitating the radar system computer to quickly generate polarization modulation commands, thereby improving modulation efficiency and stability.

[0058] Optionally, in one possible implementation, the beamline polarization angle for each modulation period is dynamically determined according to a preset detection and search strategy, including:

[0059] The beamline polarization angle is selected as any angle between 0° and 180° as the initial modulation period. Polarization detection search ranges are set on both sides of the beamline polarization angle according to the polarization detection search strategy. In each subsequent modulation period, the beamline polarization angle decreases or increases by a set step size in turn to perform polarization scanning coverage on both sides of the beamline polarization angle.

[0060] Optionally, in one possible implementation, the beamline polarization angle for each modulation period is dynamically determined according to a preset detection and search strategy, including:

[0061] After the radar detects and searches for a target, the beamline polarization angle corresponding to the echo of the detected target is used as the beamline polarization angle of the first modulation cycle. According to the detection and search strategy, polarization detection and tracking ranges are set on both sides of the beamline polarization angle. In subsequent modulation cycles, the beamline polarization angle decreases or increases in cycles according to the set step size, and the polarization detection and tracking ranges on both sides of the beamline polarization angle are alternately polarized scanned and covered.

[0062] During subsequent detection and tracking, the polarization detection and tracking range is dynamically adjusted. Within the current polarization angle range of the polarization detection and tracking scan, the beamline polarization angle with the strongest polarization response echo of the tracked target is used as the beamline polarization angle of the first modulation cycle of the next polarization scan. Polarization detection and tracking ranges are set on both sides of this beamline polarization angle. In subsequent modulation cycles, the beamline polarization angle decreases or increases periodically according to a set step size. The polarization detection and tracking ranges on both sides of the beamline polarization angle are alternately polarized scanned to cover the target, enabling dynamic polarization tracking and identification.

[0063] Optionally, in one possible implementation, dynamically determining the beamline polarization angle for each modulation period according to a preset detection and search strategy includes:

[0064] Using the modulation range as the search range, and taking the initial intermediate value of the search range as the beamline polarization angle of the current modulation period, the first processing information corresponding to the current modulation period is obtained.

[0065] The first intermediate value of the interval formed by the initial intermediate value and the maximum value of the search range, and the second intermediate value of the interval formed by the minimum value of the search range and the initial intermediate value are respectively used as the beamline polarization angles of the second modulation period and the third modulation period to obtain the second processing information corresponding to the second modulation period and the third processing information corresponding to the third modulation period.

[0066] The neighborhood centered on the beamline polarization angle corresponding to the maximum intensity among the first, second, and third processing information is selected as the search range. The step of taking the initial median value of the search range as the beamline polarization angle of the current modulation period is executed again until the width of the search range is less than a preset threshold.

[0067] In specific implementation, when the modulation range is 0° to 180°, in the first loop, the search range is 0° to 180°, with an initial intermediate value of 90°. 90° is used as the beamline polarization angle of the first modulation cycle, and the first intensity of the processed echo signal corresponding to the first modulation cycle is obtained, for example, R11. Next, the first intermediate value is determined to be 135° ((90°+180°) / 2=135°), and the second intermediate value is 45° ((0°+90°) / 2=45°). 135° is used as the beamline polarization angle of the second modulation cycle, and the second intensity of the processed echo signal corresponding to the second modulation cycle is obtained, denoted as R12. 45° is used as the beamline polarization angle of the third modulation cycle, and the third intensity of the processed echo signal corresponding to the third modulation cycle is obtained, denoted as R13.

[0068] After obtaining the first, second, and third intensities, the magnitudes of the first, second, and third intensities are compared. The neighborhood centered on the beamline polarization angle corresponding to the maximum intensity among the first, second, and third intensities is selected as the search range. The size of the search range is set according to actual needs when redefining it; in this embodiment, it is not limited.

[0069] For example, in one embodiment, the first intensity is the highest, and in this case, a new search range is redefined with 90° as the center. For example, the search range can be defined as 45° to 135°.

[0070] After the search range is redefined, the step of using the initial median value of the search range as the beam polarization angle of the current modulation period is executed again until the width of the search range is less than the preset threshold.

[0071] In this example, in the second loop, the search range is 45° to 135°, with an initial intermediate value of 90°. 90° is used as the beamline polarization angle of the first modulation period, and the first intensity of the processed echo signal corresponding to the first modulation period is obtained, for example, let's call it R1. Next, the first intermediate value is determined to be 112.5° ((90° + 135°) / 2 = 112.5°), and the second intermediate value is 67.5° ((45° + 90°) / = 67.5°). 112.5° is used as the beamline polarization angle of the second modulation period, and the second intensity of the processed echo signal corresponding to the second modulation period is obtained, let's call it R2. 67.5° is used as the beamline polarization angle of the third modulation period, and the third intensity of the processed echo signal corresponding to the third modulation period is obtained, let's call it R3.

[0072] Furthermore, repeat the above process until the search range width is less than a preset threshold. It should be noted that the search range width is the span of the polarization angle search interval in the current iteration. For example, if the initial search range is 0° to 180°, then the search range width is 180°.

[0073] Furthermore, the preset threshold is a pre-defined, relatively small angle value used to determine whether the search is sufficiently precise to terminate the iteration. When the width of the search range is less than the preset threshold, it is considered that the polarization angle has been accurately located near the target direction. Once this condition is met, the radar system stops further iterations. For example, if the preset threshold is 5°, and the two ends of the search range width in a certain iteration are 60° and 64° respectively, that is, the search range width is 4° (64°-60°=4°), which meets the termination condition, and the search ends.

[0074] It should be noted that, by determining the beamline polarization angle for each modulation cycle using the above method, the computational load required for traversal searching can be significantly reduced while maintaining search accuracy. In each round, by comparing the echo signal strengths corresponding to the current intermediate value and the points on both sides, the signal converges selectively to the region with the strongest signal, thereby quickly focusing on the optimal neighborhood where the beamline polarization angle is located.

[0075] Optionally, in one possible implementation, dynamically determining the beamline polarization angle for each modulation period according to a preset detection and search strategy includes:

[0076] Using a specified polarization angle within the modulation range as the beamline polarization angle of the first modulation period, the first processing information corresponding to the first modulation period is obtained;

[0077] The sum of the specified polarization angle and the preset angle is used as the beamline polarization angle of the second modulation period to obtain the second processing information corresponding to the second modulation period;

[0078] The difference between the specified polarization angle and the preset angle is used as the beamline polarization angle of the third modulation period to obtain the third processing information corresponding to the third modulation period.

[0079] The adjustment direction is determined based on the first processing information, the second processing information, and the third processing information;

[0080] The beamline polarization angle of the subsequent modulation period is determined according to the adjustment strategy corresponding to the adjustment direction. When the adjustment direction is to the left or right, the corresponding adjustment strategy is to update the polarization angle according to a fixed step size. When the adjustment direction is a local adjustment, the corresponding adjustment strategy is to perform fine-tuning detection with a specified polarization angle as the center.

[0081] It should be noted that the specific values ​​of the specified polarization angle and the preset angle are set according to actual needs, and are not limited in this embodiment. The following explanation uses a specified polarization angle of 60° and a preset angle of 10°.

[0082] In this example, 60° is used as the beamline polarization angle of the first modulation period to obtain the first intensity of the processed echo signal corresponding to the first modulation period. 70° is used as the beamline polarization angle of the second modulation period to obtain the second intensity of the processed echo signal corresponding to the second modulation period. 50° is used as the beamline polarization angle of the third modulation period to obtain the third intensity of the processed echo signal corresponding to the second modulation period.

[0083] After obtaining the first, second, and third intensities, the adjustment direction is determined based on their relative magnitudes. Specifically, when the third intensity is less than the first intensity and the first intensity is less than the second intensity, the adjustment direction is determined to be to the right; when the third intensity is greater than the first intensity and the first intensity is greater than the second intensity, the adjustment direction is determined to be to the left; and when the first intensity is greater than the second intensity and also greater than the third intensity, the adjustment direction is determined to be a local adjustment.

[0084] Furthermore, once the adjustment direction is determined, the beamline polarization angle for subsequent modulation cycles can be determined according to the adjustment strategy corresponding to that direction. Specifically, when the adjustment direction is to the left, the polarization angle can be decreased by a fixed step size; when the adjustment direction is to the right, the polarization angle can be increased by a fixed step size; and when the adjustment direction is a local adjustment, the polarization angle can be finely adjusted with a specified polarization angle as the center.

[0085] For example, in one embodiment, if the first intensity is maximum, the adjustment direction is a local adjustment, with fine-tuning detection performed around 60°. For example, fine-tuning detection can be performed between 55° and 65°. As another example, if the adjustment direction is determined to be to the right, 70° can be used as a reference, and the polarization angle can be updated to 75°, 80°, etc., in fixed steps (e.g., 5°). Similarly, if the adjustment direction is to the left, the polarization angle can be updated to 65°, 60°, etc., in fixed steps (e.g., 5°).

[0086] It should be noted that by conducting three explorations with a specified polarization plus a preset angle, and determining the adjustment direction based on the results of these three explorations, blind scanning or unnecessary multiple probes are avoided, greatly improving detection efficiency. Especially in complex dynamic environments, it can quickly select the optimal polarization angle in a short time, optimizing subsequent detection cycles.

[0087] Specifically, during the polarization detection and search process, the radar system transmits signals at different beamline polarization angles and analyzes the echo signal strength and characteristics corresponding to each beamline polarization angle. After acquiring this data, the radar system analyzes the correspondence between polarization angle, echo signal strength, and signal characteristics to further analyze the target's polarization response characteristics. In this process, the system continuously compares the echo signal strength and signal characteristics under different polarization angles to ultimately confirm whether the target exhibits single-peak polarization characteristics.

[0088] Specifically, after acquiring the polarization response characteristics of the target, the computer is also used to dynamically detect and track the target based on the polarization response characteristics during subsequent detection and tracking processes.

[0089] It should be noted that subsequent detection and tracking are based on the polarization response features obtained during the detection and search process, and involve targeted polarization dynamic tracking, real-time attitude analysis, and target identification of the target.

[0090] Optionally, in one possible implementation, the polarization response characteristics of the target are characterized by the intensity of the echo signal of the target at each beamline polarization angle; the detection of the target based on the target polarization response characteristics includes:

[0091] When the polarization response characteristics exhibit a single-peak feature, during the detection and tracking period, the polarization tracking range is dynamically set on both sides of the beamline polarization angle with the strongest echo in the polarization response characteristics as the center, and the target is polarized detected and tracked.

[0092] When the polarization response characteristics exhibit multi-peak features, during the detection and tracking phase, a specified scanning range is set on the beam polarization surface, which covers all peaks in the polarization response characteristics, or the neighborhood of the beamline polarization angle corresponding to each peak is scanned and detected sequentially; wherein, in the subsequent detection and tracking phase, the scanning range of the beam on the beam polarization surface is dynamically adjusted according to the detection results.

[0093] Specifically, when conducting polarization detection and search in the target airspace, if the polarization response characteristics of the target are detected to be single-peaked, in the subsequent polarization detection and tracking process, each polarization scan detection and tracking is centered on the beam polarization direction angle corresponding to the strongest target scattered echo in the previous scan, and polarization detection scan is performed in the neighborhood determined by the adopted detection strategy to perform dynamic polarization detection and tracking of the target.

[0094] When the polarization response characteristics of a target exhibit multi-peak features, multiple target polarization features can be sequentially detected and tracked during the subsequent polarization detection and tracking process. A polarization scanning and tracking neighborhood can be determined for the beamline polarization direction corresponding to the peak value of the scattered echo of each target, and scanning detection can be performed. In subsequent detection and tracking processes, the polarization direction angle of the tracking beam corresponding to the strongest scattered echo of the target in each scanning range during the previous scan is used as the center, and polarization detection and scanning are performed in the vicinity of each new polarization center, so as to realize dynamic polarization detection and tracking of multiple polarization features.

[0095] In practical implementation, for example, during the detection and search process, if a target is detected, and its polarization response characteristics are single-peaked, and the target's scattered echo is strongest at 90° of the radar beam polarization direction, then in the subsequent polarization detection and tracking process, 90° is used as the beam polarization detection scanning center, and polarization detection scanning is performed in its vicinity. For example, the beam polarization direction is controlled between 75° and 105° with a step size of 5° for polarization detection scanning. In subsequent detection and tracking processes, each polarization scan detection and tracking is performed with the beam polarization direction angle corresponding to the strongest target scattered echo from the previous scan as the center, and polarization detection scanning is performed in its vicinity, thus performing dynamic polarization detection and tracking of the target.

[0096] Furthermore, when the target's polarization response characteristics are determined to be multi-peaked, for example, when the target's scattered echo shows peaks at radar beam polarization directions of 80° and 130°, in subsequent detection and tracking processes, 80° and 130° can be used as beam polarization detection scanning centers, and polarization scanning detection and tracking can be performed sequentially within the vicinity of 80° and 130°. For example, the beam polarization direction can be controlled to perform polarization detection scanning in steps of 5° between 65° and 95° and between 115° and 145°. In subsequent detection and tracking processes, when polarizing the target's polarization characteristics, the strongest target scattered echo within each scanning range of the previous scan is used as the center, corresponding to the tracking beam polarization direction angle, and polarization detection scanning is performed within the vicinity of each new polarization center, achieving dynamic polarization detection and tracking of multiple polarization characteristics.

[0097] It should be noted that when the target's polarization response characteristics exhibit a single-peak feature, the system can dynamically detect and track the target's polarization response characteristics to maintain the linear polarization direction of the radar beam matching the target's polarization characteristics. This ensures a high signal-to-noise ratio in the radar echo, improves the radar's target tracking accuracy, and allows for analysis of target spatial attitude changes through variations in the target's polarization response characteristics. Dynamically tracking the target's polarization response characteristics helps avoid target signal loss, ensures the detection of the strongest echo signal, and thus improves the radar's target detection and tracking capabilities. For targets with multi-peak characteristics, the radar system can, as needed, dynamically detect and track multiple polarization response characteristics sequentially and analyze the target's real-time spatial attitude through real-time changes in the target's response characteristics.

[0098] Optionally, in one possible implementation, target detection is performed based on target polarization response characteristics, including:

[0099] The type of the target is analyzed based on its polarization response characteristics and the dynamic changes of those characteristics.

[0100] Based on the type of the target and the preset correspondence between the type and the detection strategy, the detection and tracking strategy for the target corresponding to that type is optimized to obtain the target detection and tracking strategy;

[0101] The target is detected based on the target polarization response characteristics and the target detection and tracking strategy.

[0102] Specifically, by analyzing and processing the polarization response characteristics of a target, its physical properties can be inferred. For example, by analyzing the single-peak or multi-peak characteristics of the polarization response curve, it can be determined whether the target is a target with a single linear reflective surface, a complex structure target with multiple reflective surfaces, or multiple targets of different types. Based on this information, the radar system can further distinguish the target type, quantity, and spatial attitude.

[0103] Furthermore, once the target type is determined, the system selects the most suitable detection strategy based on the preset correspondence between type and detection strategy. Different types of targets may have different detection requirements. For example, traditional linear scanning and modulation methods may be sufficient for some planar targets; while for complex structures or stealth targets, more refined polarization modulation, dynamic detection of multiple polarization features, or even different combinations of polarization angle modulation periods and step sizes may be required. Therefore, the computer selects the most suitable detection method based on the target type to ensure the most accurate target information is obtained in subsequent detection and tracking processes.

[0104] For example, radar systems have pre-defined detection strategies for different target types. For instance, for targets with a large radar cross-section, the detection strategy may emphasize using a large beam polarization scanning range and a large beam linear polarization angle modulation step size; while for small, slow targets with composite material structures, the detection strategy may focus on a smaller beam polarization scanning range and a smaller beam linear polarization angle modulation step size.

[0105] Understandably, after determining the detection and tracking strategy, during the target detection and tracking process, the computer adjusts and optimizes the detection strategy in real time based on the target's polarization response characteristics (i.e., the relationship between the echo signal characteristics and the beamline polarization angle). For example, for a single-peak target, the detector may dynamically focus near the peak position for fine-tuning; while for a multi-peak target, the radar system may detect and track multiple different polarization features in turn.

[0106] It should be noted that by analyzing the target's polarization response characteristics to identify the target type, and then optimizing the detection and tracking strategy based on these characteristics, the radar system dynamically adjusts the beam polarization angle of the radar linear polarization beam echo based on the received target information. This ensures the accuracy of detection and tracking. This strategy not only improves the detection capability for different types of targets but also allows for flexible adaptation to different detection needs in complex environments, significantly enhancing the intelligence and adaptability of the radar system.

[0107] The radar system provided in this embodiment, by setting a beam polarization angle modulator, can modulate the transmitted signal according to the beam polarization angle indicated by the computer. The modulation range is from 0° to 180°. In this way, the radar system can precisely control the linear polarization direction of the transmitted beam. Thus, when detecting low, small, and slow-moving targets, the detection effect is optimized by dynamically adjusting the linear polarization direction of the beam. By adjusting the linear polarization angle of the beam, the radar beam polarization direction is matched with the target polarization characteristics, increasing the target's scattering intensity on the radar beam, thereby improving the signal-to-noise ratio of the radar's received echo signal. In addition, by dynamically scanning and detecting the linear polarization surface, the radar system can fully detect and analyze the target's dynamic polarization response characteristics for target identification and target spatial attitude change analysis. In complex environments with strong low-altitude clutter interference, it can effectively improve the radar's detection capability. Furthermore, after the radar detects a target, it can dynamically detect and track the target by utilizing the target's polarization response characteristics, thereby improving the detection and tracking accuracy in complex environments with multiple targets. In summary, the radar system provided in this embodiment significantly improves the radar system's ability to detect small, slow targets by utilizing the polarization angle modulation of the radar beamline for polarization detection and search in the target airspace, target identification, real-time spatial dynamic attitude detection and analysis, and polarization detection and tracking.

[0108] In addition to providing a radar system, this application also provides a method for target detection using a radar system. The method for target detection using a radar system provided in this application is described below.

[0109] Specifically, Figure 4 This is a flowchart illustrating an embodiment of the target detection method using a radar system provided in this application. Please refer to... Figure 4 The target detection method using a radar system provided in this embodiment is applied to a computer within the radar system, and the method includes:

[0110] S401. Dynamically determine the beamline polarization angle of each modulation period according to the preset detection and search strategy; the modulation period is equal to an integer multiple of the coherent processing interval of the radar system, the beamline polarization angle corresponding to each modulation period remains unchanged, and the beamline polarization angle in different modulation periods changes dynamically according to the detection and search strategy.

[0111] S402. Based on the beamline polarization angle corresponding to each modulation period and the processing information corresponding to that modulation period, determine the polarization response characteristics of the target.

[0112] S403. During the detection and tracking of the target after its discovery, the target is detected based on the target polarization response characteristics.

[0113] Specifically, in step S401, during the polarization detection search phase of the target airspace, the beamline polarization angle for each modulation period is dynamically determined according to the polarization detection search strategy. For example, in the first modulation period, the beamline polarization angle is set to 20°, and in the second modulation period, the beamline polarization angle is set to 21°.

[0114] Referring to the preceding description, the modulation period is equal to the integer part of the coherent processing interval of the radar system. The beamline polarization angle remains unchanged within one modulation period during the polarization detection and search process of the target airspace, while the beamline polarization angle is different in different modulation periods.

[0115] Specifically, the modulation period is set to an integer multiple of the coherent processing interval. The corresponding radar beamline polarization angle remains constant within each modulation period. The beamline polarization angle dynamically changes according to the beam polarization detection search strategy across different modulation periods, and the spatial pointing of each beam is dynamically determined according to the beam detection strategy. Maintaining a consistent polarization angle within each modulation period aligns the modulation period with the coherent processing interval, simplifying the radar system control logic, reducing uncertainties in signal processing, and making the polarization characteristics of the echo signal more stable. This facilitates the analysis of the target's polarization response and avoids problems such as coherent accumulation breaks or blurred processing boundaries introduced during polarization angle modulation. The dynamic change of the beamline polarization angle according to the beam polarization detection strategy across different modulation periods allows the radar system to detect the target's polarization characteristics from different angles. Different beamline polarization angles cause different responses in the target's scattered echoes. This variation allows the radar to more fully detect the target's polarization characteristics, thereby acquiring more of the target's polarization response features.

[0116] In step S402, when performing polarization detection search and airspace scanning detection search on the target airspace, the polarization angle of the radar transmitted beam, the intensity characterization of the echo signal, and the set signal-to-noise ratio threshold are used to analyze whether the target is detected, analyze the polarization response characteristics of the target, and analyze the type of the target.

[0117] For details on the specific implementation process and principle of this step, please refer to the description in the previous embodiments, which will not be repeated here.

[0118] Furthermore, in step S403, during the detection and tracking process after the target is detected, dynamic polarization feature detection and tracking of the target is performed based on the target polarization response characteristics.

[0119] Understandably, targets are detected and tracked based on their polarization response characteristics during subsequent detection and tracking. By analyzing the target's polarization response characteristics, the computer can analyze and identify the target type. For example, if a target exhibits a single echo peak, it indicates that the target has a single linear reflective surface, and a single polarization feature detection and tracking strategy can be adopted. Conversely, if the target's polarization response exhibits multiple peaks, it means that the target has multiple reflective surfaces, complex geometry, or is a target of multiple different types. The computer can then adopt a strategy of simultaneously detecting and tracking multiple polarization features to ensure real-time target detection and tracking, understand target dynamics, assess target hazard, and generate timely safety warnings.

[0120] As described above, it is understood that the detection capability and performance of radar systems can be improved through the above methods. This method is particularly suitable for the detection, identification, target hazard assessment, and safety early warning of small, slow targets in the field of low-altitude safety three-dimensional perception.

[0121] This method involves acquiring, processing, and analyzing echo signals at different beam linear polarization angles during the detection and search phase. Based on a signal-to-noise ratio threshold set by the detection strategy, it determines whether a target has been detected, constructing the target's response characteristics along the polarization angle dimension to identify its polarization response features. Building upon this, the radar system can dynamically adjust the linear polarization angle of the detection beam during the subsequent detection and tracking phases, achieving dynamic target detection and tracking. This approach fully leverages the differences in the scattering response of targets to linearly polarized waves with different polarization directions, significantly improving the radar system's detection capability and performance against low-altitude small targets, and is particularly suitable for detecting small or micro UAVs using composite materials.

[0122] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A radar system, characterized by The radar system comprises a beam emission control component, a polarization angle modulator, a linear polarization direction adjustable antenna array, a signal receiving and processing unit and a computer; The beam emission control component is configured to generate an emission signal according to a waveform and a beam position indicated by the computer; The polarization angle modulator is configured to modulate the emission signal according to a linear polarization angle of the radar beam indicated by the computer, so that the linear polarization angle of the modulated radar beam signal dynamically changes; the modulation range of the polarization angle modulator is 0° to 180°, covering the entire polarization plane; The antenna array is configured to emit the radar beam signal and receive a return signal of the radar beam signal; The signal receiving and processing unit is configured to receive the return signal, process the return signal, and send processing information to the computer; The computer is configured to dynamically determine the linear polarization angle of each modulation period according to a preset detection search strategy; the modulation period is an integer multiple of the coherent processing interval of the radar system; the corresponding linear polarization angle in each modulation period remains unchanged, and the linear polarization angles in different modulation periods dynamically change according to the detection search strategy; the computer is further configured to determine the polarization response characteristics of the target based on the corresponding linear polarization angle of each modulation period and the processing information corresponding to the modulation period; The computer is further configured to detect the target according to the polarization response characteristics of the target during the detection and tracking of the target; the polarization response characteristics of the target are represented by the intensity of the return signal of the target at each linear polarization angle; The detection of the target according to the polarization response characteristics of the target comprises: When the polarization response characteristics exhibit a single-peak characteristic, during the detection and tracking, a linear polarization angle corresponding to a return signal with the strongest intensity in the polarization response characteristics is taken as the center, and a polarization tracking range is dynamically set on both sides of the linear polarization angle, so as to perform polarization detection and tracking on the target; When the polarization response characteristics exhibit a multi-peak characteristic, during the detection and tracking, a specified scanning range is set on the beam polarization plane, the specified scanning range covers all peaks in the polarization response characteristics, or the neighborhood of the linear polarization angle corresponding to each peak is scanned and tracked in sequence; wherein, during the subsequent detection and tracking stage, the scanning range of the beam on the beam polarization plane is dynamically adjusted according to the detection result.

2. The radar system of claim 1, wherein, The determination of the linear polarization angle of each modulation period according to the preset detection search strategy comprises: Any angle between 0° and 180° is selected as the linear polarization angle of the initial modulation period during the detection and search, and in each subsequent modulation period, the linear polarization angle is increased by a set step size period by period until the search range specified by the polarization detection search strategy is covered; Or, Any angle between 0° and 180° is selected as the linear polarization angle of the initial modulation period, and in each subsequent modulation period, the linear polarization angle is decreased by a set step size period by period until the search range specified by the polarization detection search strategy is covered; Or, Select any angle between 0° and 180° as the beam line polarization angle of the initial modulation period, and set the polarization detection search range on both sides of the beam line polarization angle according to the detection search strategy, and in each subsequent modulation period, the beam line polarization angle is reduced or increased by a set step size, and the polarization detection search range on both sides of the beam line polarization angle is alternately scanned and covered.

3. The radar system of claim 1, wherein, The beam line polarization angle of each modulation period is dynamically determined according to the preset detection search strategy, comprising: Taking the modulation range as the search range, and taking the initial middle value of the search range as the beam line polarization angle of the current modulation period, the first processing information corresponding to the current modulation period is obtained. The first middle value of the interval formed by the initial middle value and the maximum value of the search range, and the second middle value of the interval formed by the minimum value of the search range and the initial middle value are taken as the beam line polarization angle of the second modulation period and the third modulation period, and the second processing information corresponding to the second modulation period and the third processing information corresponding to the third modulation period are obtained. Select the neighborhood with the beam line polarization angle corresponding to the maximum intensity in the first processing information, the second processing information and the third processing information as the search range, and execute the step of taking the initial middle value of the search range as the beam line polarization angle of the current modulation period again until the width of the search range is less than a preset threshold.

4. The radar system of claim 1, wherein, The beam line polarization angle of each modulation period is dynamically determined according to the preset detection search strategy, comprising: Taking the specified polarization angle in the modulation range as the beam line polarization angle of the first modulation period, the first processing information corresponding to the first modulation period is obtained. Taking the sum of the specified polarization angle and the preset angle as the beam line polarization angle of the second modulation period, the second processing information corresponding to the second modulation period is obtained. Taking the difference between the specified polarization angle and the preset angle as the beam line polarization angle of the third modulation period, the third processing information corresponding to the third modulation period is obtained. According to the first processing information, the second processing information and the third processing information, the adjustment direction is determined. The beam line polarization angle of the subsequent modulation period is determined according to the adjustment strategy corresponding to the adjustment direction; wherein, when the adjustment direction is left adjustment or right adjustment, the corresponding adjustment strategy is to update the polarization angle according to a fixed step size; when the adjustment direction is local adjustment, the corresponding adjustment strategy is to fine tune the detection with the specified polarization angle as the center.

5. The radar system of claim 1, wherein, The target is detected according to the target polarization response characteristics, comprising: According to the polarization response characteristics of the target and the dynamic change of the polarization response characteristics, the type of the target is analyzed; According to the type of the target and the corresponding relationship between the preset type and the detection tracking strategy, the detection tracking strategy of the target corresponding to the type is optimized to obtain a target detection tracking strategy; The target is detected according to the target polarization response characteristics and the target detection tracking strategy.

6. The radar system of claim 1 or 2, wherein, The beam line polarization angle modulation range covers the detection scanning range of the radar beam signal in the polarization plane.

7. A method for target detection using a radar system, characterized in that The method is applied to a computer in the radar system, and the method comprises: The beam line polarization angle of each modulation period is dynamically determined according to a preset detection search strategy; the modulation period is equal to an integer multiple of a coherent processing interval of the radar system, the corresponding beam line polarization angle in each modulation period remains unchanged, and the beam line polarization angles in different modulation periods dynamically change according to the preset detection search strategy; The polarization response characteristics of the target are determined based on the corresponding beam line polarization angle of each modulation period and the processing information corresponding to the modulation period; during the detection and tracking of the target after the target is found, the target is detected according to the polarization response characteristics of the target; the polarization response characteristics of the target are represented by the intensity of the echo signal of the target at each beam line polarization angle; the detection of the target according to the polarization response characteristics of the target comprises: When the polarization response characteristics exhibit single-peak characteristics, during the detection and tracking, the polarization tracking range is dynamically set on both sides of the beam line polarization angle corresponding to the echo signal with the strongest intensity in the polarization response characteristics, and the target is polarimetrically detected and tracked; When the polarization response characteristics exhibit multi-peak characteristics, during the detection and tracking, a specified scanning range is set on the beam polarization plane, the specified scanning range covers all peaks in the polarization response characteristics, or the neighborhood of the beam line polarization angle corresponding to each peak is scanned and detected in turn; wherein, during the subsequent detection and tracking stage, the scanning range of the beam on the beam polarization plane is dynamically adjusted according to the detection results.

8. The method of claim 7, wherein, The beam line polarization angle of each modulation period is dynamically determined according to a preset detection search strategy; the modulation period is equal to an integer multiple of a coherent processing interval of the radar system, the corresponding beam line polarization angle in each modulation period remains unchanged, and the beam line polarization angles in different modulation periods dynamically change according to the preset detection search strategy; Any angle between 0° and 180° is selected as the beam line polarization angle of the initial modulation period during detection search, and in each subsequent modulation period, the beam line polarization angle is increased by a set increment step by step until the search range specified by the polarization detection search strategy is covered; Or, Any angle between 0° and 180° is selected as the beam line polarization angle of the initial modulation period, and in each subsequent modulation period, the beam line polarization angle is decreased by a set decrement step by step until the search range specified by the polarization detection search strategy is covered; Or, Any angle between 0° and 180° is selected as the beam line polarization angle of the initial modulation period, and the polarization detection search range is set on both sides of the beam line polarization angle according to the polarization detection search strategy, and in each subsequent modulation period, the beam line polarization angle is decreased or increased by a set step to alternately cover the polarization detection search ranges on both sides of the beam line polarization angle.

9. The method of claim 7, wherein, The modulatable range of the beam line polarization angle covers the detection scanning range of the radar beam signal on the polarization plane.

Images