An antenna layout method and system for ground penetrating radar receive end beamforming

Abstract

The application relates to an antenna layout method and system for ground penetrating radar receiving end beam forming, and relates to the field of ground penetrating radar detection. The method solves the problem that, in a conventional ground penetrating radar, a multi-channel scheme is adopted, the number of transmitting and receiving antennas is increased to improve the lateral detection range, and due to time lag of channel data and beam forming difficulty, the potential of the array antenna cannot be fully utilized. The method comprises the following steps: determining the form of a ground penetrating radar antenna array according to the requirement of beam forming; constructing an equivalent directional diagram of the antenna array layout according to the form of the radar antenna array; suppressing the grating lobe phenomenon in the equivalent directional diagram of the antenna array layout; suppressing the coupling effect in the equivalent directional diagram of the antenna array layout; and suppressing the direct wave from the transmitting antenna to the receiving antenna according to the polarization direction of the antenna in the suppressed equivalent directional diagram, so as to complete the antenna layout. The application is applied to the field of underground nondestructive imaging.

Description

Technical Field

[0001] This invention relates to the field of ground penetrating radar detection, and more particularly to an antenna layout method for beamforming at the receiver of a ground penetrating radar. Background Technology

[0002] Ground-penetrating radar (GPR) is a widely used sensing method with broad applications in non-destructive imaging of underground structures. Currently, based on their structure, GPR can be categorized into single-channel and multi-channel GPR. Single-channel GPR uses a pair of transmitting and receiving antennas to send and receive electromagnetic signals; its structure is relatively simple, and it can be used for detection operations via handheld or cart-mounted methods. Multi-channel GPR typically has multiple sets of transmitting and receiving antennas, resulting in greater structural complexity and system weight; it is often deployed using cart-mounted or vehicle-mounted methods.

[0003] In current applications, ground-penetrating radar (GPR) is used in scenarios such as bridge inspection, roadbed inspection, airport runway inspection, and tunnel inspection. These applications require GPR to have high operational efficiency, enabling rapid and efficient detection to minimize impact on production and daily life. GPR can continuously detect along the direction of vehicle movement, and the detection range in the direction perpendicular to the direction of movement (hereinafter referred to as the lateral direction) directly determines the operational efficiency. If the GPR has a larger operating range, it can complete the measurement of a larger area in a single scan, thereby significantly improving the efficiency of detection operations.

[0004] To improve the lateral detection range of ground-penetrating radar (GPR), the current common solution is to use multi-channel GPR, increasing the number of transmitting and receiving antennas to enhance its lateral detection range. Currently, most multi-channel GPRs simply stitch together the collected data according to the relative positions of the antennas during data processing, which fails to fully utilize the advantages of array antennas. In multistatic GPR, the number of transmitting and receiving antennas is often the same, and the antennas are in one-to-one correspondence; each receiving antenna only collects the echo signal from one transmitting antenna.

[0005] Multi-channel ground-penetrating radars (GPRs) employ multiple sets of transmit and receive antennas, allowing for various antenna combinations. Combining these antennas with beamforming techniques using different methods can acquire data from multiple directions, thereby improving the lateral detection range and resolution accuracy of the GPR. However, most current multi-channel GPRs use radio frequency switches for time-division multiplexing of transmit and receive signals. Typically, only one set of transmit and receive antennas is active at any given time. Therefore, the data acquired by the receiver of a multi-channel GPR is not entirely simultaneous. In this situation, the data acquired by each receiving antenna has a time lag, making it unsuitable for direct beamforming. Furthermore, since this time lag originates from analog circuitry, its variation range is significant, making effective correction difficult. Summary of the Invention

[0006] This invention addresses the problem that traditional ground-penetrating radar (GPR) employs a multi-channel approach, increasing the number of transmitting and receiving antennas to improve the lateral detection range. However, due to channel data time lag and difficulties in beamforming, the potential of the array antenna cannot be fully utilized. This invention proposes an antenna layout method for beamforming at the GPR receiver, the method comprising:

[0007] The form of the ground-penetrating radar antenna array is determined based on the beamforming requirements.

[0008] Construct the equivalent radiation pattern of the antenna array layout based on the form of the radar antenna array;

[0009] Suppress grating lobe phenomena in the equivalent radiation pattern of the antenna array layout;

[0010] The coupling effect in the equivalent radiation pattern of the antenna array layout is suppressed;

[0011] Based on the polarization direction of the antenna with the suppressed equivalent radiation pattern, the direct wave from the transmitting antenna to the receiving antenna is suppressed, thus completing the antenna layout.

[0012] Furthermore, a preferred embodiment is also provided, wherein determining the form of the ground-penetrating radar antenna array according to the beamforming requirements includes:

[0013] Four receiving antennas are arranged symmetrically along the vertical axis in a linear manner with equal spacing.

[0014] The transmitting antenna is placed at the vertical axis;

[0015] The transmitter adopts a single-channel structure and is connected to the signal source, while the receiver adopts a four-channel structure, with each channel equipped with an independent high-speed ADC.

[0016] Furthermore, a preferred embodiment is also provided, wherein constructing the equivalent radiation pattern of the antenna array layout based on the form of the radar antenna array includes:

[0017] Calculate the radiation pattern of each antenna element based on the position of the antenna elements in the ground-penetrating radar antenna array;

[0018] The radiation patterns of each antenna element are superimposed to obtain the actual radiation pattern of the antenna array.

[0019] The equivalent radiation pattern of the antenna array layout is obtained by normalizing the actual radiation pattern of the antenna array.

[0020] Furthermore, a preferred embodiment is provided, wherein suppressing the grating lobe phenomenon in the equivalent radiation pattern of the antenna array layout includes:

[0021] The beam angle can be calculated by solving the phase shift function;

[0022] The beam angle is formed by periodically adjusting the phase.

[0023] The position of the grating lobe is determined based on the relationship between the beamforming main lobe angle and the phase of the antenna radiated signal.

[0024] Adjust the antenna array spacing according to the position of the grating lobes to suppress grating lobe formation.

[0025] Furthermore, a preferred method is also provided, wherein the beam angle can be calculated by solving the phase shift function, specifically as follows:

[0026]

[0027] Where Φ is the antenna radiation phase delay, d is the distance between antenna elements, θ is the main lobe angle, and λ is the wavelength of the transmitted / received signal.

[0028] Furthermore, a preferred embodiment is also provided, wherein determining the position of the grating lobe based on the relationship between the beamforming main lobe angle and the phase of the antenna radiated signal specifically involves:

[0029]

[0030] Where m = 0, ±1, ±2...

[0031] Furthermore, a preferred method is provided to suppress coupling effects in the equivalent radiation pattern of the antenna array layout, including setting the spacing of the receiving antennas to λ / 2.

[0032] Based on the same inventive concept, the present invention also provides an antenna layout system for beamforming at a ground-penetrating radar receiver, the system comprising:

[0033] The radar antenna array determination unit is used to determine the form of the ground-penetrating radar antenna array according to the beamforming requirements.

[0034] Equivalent radiation pattern construction unit, used to construct the equivalent radiation pattern of the antenna array layout according to the form of the radar antenna array;

[0035] A grating lobe suppression unit is used to suppress grating lobe phenomena in the equivalent radiation pattern of the antenna array layout;

[0036] A coupling suppression unit is used to suppress coupling effects in the equivalent radiation pattern of the antenna array layout;

[0037] The direct wave suppression unit is used to suppress the direct wave from the transmitting antenna to the receiving antenna according to the polarization direction of the antenna in the suppressed equivalent radiation pattern, thus completing the antenna layout.

[0038] Based on the same inventive concept, the present invention also provides a computer-readable storage medium for storing a computer program that executes an antenna layout method for beamforming at a ground-penetrating radar receiver as described in any of the preceding claims.

[0039] Based on the same inventive concept, the present invention also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program stored in the memory, the processor executes an antenna layout method for beamforming at a ground-penetrating radar receiver according to any one of the above-mentioned methods.

[0040] The advantages of this invention are:

[0041] This invention solves the problem that traditional ground-penetrating radars, which use a multi-channel approach to increase the lateral detection range by increasing the number of transmitting and receiving antennas, cannot fully utilize the potential of the array antennas due to channel data time lag and beamforming difficulties.

[0042] This invention proposes an antenna layout method for beamforming at the receiver of a ground-penetrating radar. By increasing the number of transmitting and receiving antennas, the lateral detection range of the radar can be improved, enabling it to cover a wider area. This enhances the detection capability of the radar system. By suppressing grating lobe phenomena and coupling effects in the equivalent radiation pattern, unwanted beamforming directions can be reduced, interference can be decreased, and thus the directivity and accuracy of the radar system can be improved. Traditional multi-channel schemes may be limited by the time lag of channel data and the difficulty of beamforming, failing to fully realize the potential of the array antenna. This method overcomes these problems by optimizing the antenna layout to meet the requirements of beamforming. Based on the suppressed equivalent radiation pattern, the direct wave from the transmitting antenna to the receiving antenna can be suppressed, thereby further optimizing beamforming to meet the needs of specific applications and improving detection performance. Traditional methods are limited by the time lag of channel data and the difficulty of beamforming. This method aims to overcome these obstacles by optimizing the antenna layout, thereby improving the real-time performance and response speed of the radar system.

[0043] This invention proposes a preferred embodiment of an antenna layout method for beamforming at a ground-penetrating radar (GPR) receiver. This method addresses the problems of time lag in channel data and difficulties in beamforming when using multi-channel GPR schemes, which prevent the full utilization of the array antenna's potential. It introduces a new approach, designing the antenna array based on beamforming theory. One antenna transmits the signal, while four receiving antennas, each equipped with an independent ADC, synchronously acquire the signal, ensuring good signal time consistency. This array layout meets the requirements for data processing using beamforming methods. The integrated processing of four-channel data by beamforming improves the detection range and resolution performance of the GPR.

[0044] In a preferred embodiment of the antenna layout method for beamforming at a ground-penetrating radar receiver, the design of the receiver antenna array layout takes into account the influence of the spacing between antenna elements on the grating lobe performance of the radiation pattern and the coupling between antenna elements. This consideration not only effectively avoids false targets appearing after data processing using beamforming methods, but also effectively improves the main lobe gain of the equivalent radiation pattern, thereby effectively improving the signal-to-noise ratio of the received signal.

[0045] In a preferred embodiment of the antenna layout method for beamforming at the receiver of a ground-penetrating radar, a different lateral polarization direction than that of traditional multi-channel ground-penetrating radars is adopted. This polarization effectively reduces the signal directly reaching the receiver from the transmitting antenna, effectively suppresses the intensity of the direct wave, ensures good consistency among the four channels, and effectively improves the accuracy of the acquired data.

[0046] This invention is applied to the field of underground non-destructive imaging. Attached Figure Description

[0047] Figure 1 This is a flowchart of an antenna layout method for beamforming at a ground-penetrating radar receiver, as described in Embodiment 1.

[0048] Figure 2 This is a schematic diagram of the single-channel transmit and four-channel receive antenna array layout described in Embodiment 2;

[0049] Figure 3 This is a schematic diagram of the polarization of the antenna array motion direction as described in Implementation Method Eleven;

[0050] Figure 4 This is a schematic diagram of the polarization of the antenna array perpendicular to the direction of motion as described in Embodiment Eleven. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0052] Implementation Method 1: Participation Figure 1 This embodiment describes an antenna layout method for beamforming at a ground-penetrating radar receiver, the method comprising:

[0053] The form of the ground-penetrating radar antenna array is determined based on the beamforming requirements.

[0054] Construct the equivalent radiation pattern of the antenna array layout based on the form of the radar antenna array;

[0055] Suppress grating lobe phenomena in the equivalent radiation pattern of the antenna array layout;

[0056] The coupling effect in the equivalent radiation pattern of the antenna array layout is suppressed;

[0057] Based on the polarization direction of the antenna with the suppressed equivalent radiation pattern, the direct wave from the transmitting antenna to the receiving antenna is suppressed, thus completing the antenna layout.

[0058] This implementation increases the radar's lateral detection range by increasing the number of transmitting and receiving antennas, enabling it to cover a wider area. This improves the radar system's detection capability. By suppressing grating lobe phenomena and coupling effects in the equivalent radiation pattern, unwanted beamforming directions can be reduced, interference can be decreased, and thus the radar system's directivity and accuracy can be improved. Traditional multi-channel schemes may be limited by time lag in channel data and difficulties in beamforming, failing to fully realize the potential of the array antenna. This method overcomes these problems by optimizing the antenna layout to meet beamforming requirements. Based on the suppressed equivalent radiation pattern, direct waves from the transmitting antenna to the receiving antenna can be suppressed, further optimizing beamforming to suit specific application needs.

[0059] The primary objective of this implementation is to improve traditional multi-channel ground-penetrating radar (GPR) systems, enabling them to more effectively address diverse environmental and application requirements and enhance detection performance. Traditional methods may be limited by time lag in channel data and difficulties in beamforming. This method aims to overcome these obstacles by optimizing antenna layout, thereby improving the real-time performance and response speed of the radar system. The proposed method first determines the form of the GPR antenna array based on specific beamforming requirements, which forms the basis of a directional radar system. Based on the selected antenna array form, an equivalent radiation pattern of the antenna array layout is constructed. This radiation pattern shows the array's sensitivity and response in different directions. Grating lobe phenomena and coupling effects in the equivalent radiation pattern are suppressed to reduce unwanted beamforming directions, improving the radar system's directionality and accuracy. Based on the suppressed equivalent radiation pattern, the direct wave from the transmitting antenna to the receiving antenna is suppressed to further optimize beamforming, adapting it to the specific application requirements. Through these steps, an optimized antenna layout is obtained, enabling the GPR system to achieve better performance in specific application scenarios.

[0060] Implementation Method Two: This implementation method further defines the antenna layout method for beamforming at a ground-penetrating radar receiver described in Implementation Method One. The step of determining the form of the ground-penetrating radar antenna array according to the beamforming requirements includes:

[0061] Four receiving antennas are arranged symmetrically along the vertical axis in a linear manner with equal spacing.

[0062] The transmitting antenna is placed at the vertical axis;

[0063] The transmitter adopts a single-channel structure and is connected to the signal source, while the receiver adopts a four-channel structure, with each channel equipped with an independent high-speed ADC.

[0064] This embodiment enhances the directivity of the radar system by symmetrically arranging four receiving antennas along the vertical axis, making it easier to acquire and locate targets. The equidistant linear layout helps form a narrow beam, improving the certainty of target direction. The four-channel structure, with each channel equipped with an independent high-speed ADC, allows for the reception and processing of signals from multiple channels, ensuring good signal time consistency and improving the radar system's detection performance. Each single-channel transmitter is connected to a signal source, allowing the transmitted signal to be beamformed across the entire receiving antenna array. This helps reduce system complexity and fully utilizes data from the multi-channel receivers.

[0065] This embodiment utilizes an array layout that meets the requirements for data processing using beamforming methods. Beamforming, by integrating data from four channels, enhances the detection range and resolution of the ground-penetrating radar. Employing a single-channel transmitter reduces system complexity while maintaining the capability of a multi-channel receiver, thus lowering maintenance costs and design complexity. The four receiver antennas are symmetrically placed linearly and at equal intervals along the vertical axis. This layout helps form a narrower beam, improving the radar system's directivity. The single-channel transmitter structure means that only one antenna is used to transmit the signal. This signal can be beamformed through phase control for target orientation and tracking. The four-channel receiver structure, with each channel equipped with an independent high-speed ADC, allows the system to simultaneously receive and process data from multiple channels, improving detection performance.

[0066] Implementation Method 3: This implementation method further defines the antenna layout method for beamforming at a ground-penetrating radar receiver described in Implementation Method 1. The step of constructing the equivalent radiation pattern of the antenna array layout based on the form of the radar antenna array includes:

[0067] Calculate the radiation pattern of each antenna element based on the position of the antenna elements in the ground-penetrating radar antenna array;

[0068] The radiation patterns of each antenna element are superimposed to obtain the actual radiation pattern of the antenna array.

[0069] The equivalent radiation pattern of the antenna array layout is obtained by normalizing the actual radiation pattern of the antenna array.

[0070] The purpose of this implementation is to optimize the beamforming of a ground-penetrating radar system to improve the accuracy of target detection and localization. By constructing an equivalent radiation pattern, the beamforming process can be better understood and controlled, making it more adaptable to specific application requirements. By calculating and superimposing the radiation pattern of each antenna element, this method helps to enhance the directivity of the radar system. This means the system can point more accurately at the target or area of ​​interest, reducing unnecessary background interference. By normalizing the actual radiation pattern, the system performance can be better controlled, adapting it to different operating environments and conditions. This contributes to improving the performance and flexibility of the radar system.

[0071] This implementation first calculates the radiation pattern of each antenna element in the ground-penetrating radar antenna array based on its position. This is a process representing the response pattern of each element to different directions. The radiation pattern describes the sensitivity of the antenna element in different directions. The radiation patterns of each element are superimposed to obtain the actual radiation pattern of the antenna array. This actual radiation pattern reflects the beamforming characteristics of the entire antenna array, i.e., the sensitivity of the radar system to different directions. The actual radiation pattern is normalized to obtain the equivalent radiation pattern of the antenna array layout. This normalization process is typically used to ensure that the amplitude of the radiation pattern is within a specific range in order to better control system performance. This can include enhancing the amplitude of the main beam, reducing sidelobe interference, etc. By considering the radiation pattern of each antenna element, the system can better orient and focus the beam, thereby improving the directionality and accuracy of target detection. By optimizing beamforming, the influence of background interference or signals from directions of non-interest can be reduced, thereby improving the performance of the radar system. Through normalization, the performance of the system can be adjusted to meet different application requirements and operating conditions, providing greater flexibility.

[0072] Implementation Method Four: This implementation method further defines the antenna layout method for beamforming at a ground-penetrating radar receiver described in Implementation Method One. The suppression of grating lobe phenomena in the equivalent radiation pattern of the antenna array layout includes:

[0073] The beam angle can be calculated by solving the phase shift function;

[0074] The beam angle is formed by periodically adjusting the phase.

[0075] The position of the grating lobe is determined based on the relationship between the beamforming main lobe angle and the phase of the antenna radiated signal.

[0076] Adjust the antenna array spacing according to the position of the grating lobes to suppress grating lobe formation.

[0077] A grating lobe is a radiation lobe with an intensity similar to the main lobe, generated by the in-phase superposition of the antenna's radiated fields. For transmitter beamforming, the grating lobe consumes a significant amount of radiated energy, leading to a decrease in the main lobe's gain performance. For receiver beamforming, the grating lobe receives interference from other directions, causing false targets and affecting the determination of target location. This implementation reduces or suppresses the grating lobe, allowing the system to better concentrate signal energy, narrowing the main lobe, thereby improving directivity and the accuracy of target positioning.

[0078] This embodiment first calculates the beam direction by solving the phase shift function based on the phase information of the antenna layout at the receiving end. The signal phase difference in different directions is obtained from the phase shift function, thereby determining the beam pointing. To control the main lobe angle of the beam, the phase can be adjusted to have periodic variations. This can be achieved by introducing a specific phase difference between the antenna elements. This periodic adjustment helps determine the main lobe angle. By studying the relationship between the beamforming main lobe angle and the phase of the antenna radiated signal, the position of the grating lobes can be determined. Grating lobes typically form under specific phase conditions in different directions. To suppress grating lobe formation, this embodiment adjusts the spacing of the antenna array. By adjusting the distance between the antenna elements, the beam shape can be better controlled to suppress the occurrence of grating lobes.

[0079] Implementation Method Five: This implementation method further defines the antenna layout method for beamforming at a ground-penetrating radar receiver described in Implementation Method Four. Specifically, the beam angle can be calculated by solving the phase shift function.

[0080]

[0081] Where Φ is the antenna radiation phase delay, d is the distance between antenna elements, θ is the main lobe angle, and λ is the wavelength of the transmitted / received signal.

[0082] Implementation Method Six: This implementation method further defines the antenna layout method for beamforming at a ground-penetrating radar receiver described in Implementation Method Four. Specifically, determining the grating lobe position based on the relationship between the beamforming main lobe angle and the phase of the antenna radiated signal involves:

[0083]

[0084] Where m = 0, ±1, ±2...

[0085] This implementation method will be explained in conjunction with Implementation Method 5. Since the arcsin function can only generate real solutions within the range of -1 to +1, no real solutions can be obtained outside this range. Simultaneously, utilizing phase periodicity, it repeats with a period of 2π, and (m×2π+ΔΦ) is used instead of ΔΦ. Furthermore, to avoid the goal of obtaining a single real solution from the grating lobes, it can be written as:

[0086]

[0087] Here, m takes the values ​​m = 0, ±1, ±2L. If we want there to be only one m that satisfies the above requirement, that is, for all cases |m|≥1, arcsin>1, then we can solve for d≤λ / 2.

[0088] Implementation Method Seven: This implementation method further defines the antenna layout method for beamforming at the ground-penetrating radar receiver described in Implementation Method One. It suppresses the coupling effect in the equivalent radiation pattern of the antenna array layout, including setting the spacing of the receiving antennas to λ / 2.

[0089] In practical applications, the distance between receiving antennas is not necessarily better the smaller it is. When the distance between receiving antennas is too close, coupling effects will occur, which will directly affect the matching performance of the antennas and limit their radiation capability. Therefore, the spacing between the antennas should be increased as much as possible within a reasonable range. Thus, the final spacing between the receiving antennas is set to λ / 2.

[0090] Implementation Method 8: An antenna layout system for beamforming at a ground-penetrating radar receiver, as described in this implementation method, includes:

[0091] The radar antenna array determination unit is used to determine the form of the ground-penetrating radar antenna array according to the beamforming requirements.

[0092] Equivalent radiation pattern construction unit, used to construct the equivalent radiation pattern of the antenna array layout according to the form of the radar antenna array;

[0093] A grating lobe suppression unit is used to suppress grating lobe phenomena in the equivalent radiation pattern of the antenna array layout;

[0094] A coupling suppression unit is used to suppress coupling effects in the equivalent radiation pattern of the antenna array layout;

[0095] The direct wave suppression unit is used to suppress the direct wave from the transmitting antenna to the receiving antenna according to the polarization direction of the antenna in the suppressed equivalent radiation pattern, thus completing the antenna layout.

[0096] Implementation Method Nine: A computer-readable storage medium according to this implementation method, the computer-readable storage medium being used to store a computer program, the computer program executing an antenna layout method for beamforming at a ground-penetrating radar receiver as described in any one of Implementation Methods One to Seven.

[0097] Implementation Method 10: A computer device according to this implementation method includes a memory and a processor. The memory stores a computer program. When the processor runs the computer program stored in the memory, the processor executes an antenna layout method for beamforming at a ground-penetrating radar receiver according to any one of Implementation Methods 1 to 7.

[0098] Implementation Method Eleven: This implementation method provides a specific embodiment of the antenna layout method for beamforming at the ground-penetrating radar receiver described in Implementation Method One, and also serves to explain Implementation Methods Two to Seven. Specifically:

[0099] This invention addresses beamforming at the receiver end of ground-penetrating radar (GPR) and proposes a single-channel transmit and four-channel receive antenna layout. This layout requires consideration of signal acquisition synchronization, pattern grating lobe suppression and antenna coupling suppression, and direct wave suppression from the transmit antenna to the receive antenna. The antenna array layout process is as follows: Figure 1 As shown.

[0100] Specifically, the form of the ground-penetrating radar antenna array needs to be determined first based on the beamforming requirements. In the antenna array designed in this invention, beamforming is performed at the receiving end; therefore, multiple receiving antennas need to be arranged at the receiving end. To facilitate the production and processing of the array antenna, the transmitting antennas are placed symmetrically along the axis, and the four receiving antennas are placed symmetrically along the axis in a linear manner with equal spacing, such as... Figure 2 As shown, the transmitting end adopts a single-channel structure connected to the signal source, while the receiving end adopts a four-channel structure, with each channel equipped with an independent high-speed ADC, and all four channels can achieve synchronous sampling. During the detection process, the signal transmitted by transmitting antenna 1 is simultaneously acquired by receiving antennas 1, 2, 3, and 4. The signals acquired in this way can ensure good time consistency. By using beamforming to process the signals acquired in the four directions, target information in the fan-shaped area below the antenna array can be obtained.

[0101] After determining the antenna array configuration, the spacing between the antenna elements needs to be further determined. During beamforming, as the main lobe angle changes, a grating lobe phenomenon may appear in the equivalent radiation pattern. The grating lobe is a radiation lobe with a similar intensity to the main lobe, generated by the in-phase superposition of the antenna radiation fields. For transmitter beamforming, the grating lobe occupies a significant amount of radiated energy, leading to a decrease in the main lobe's gain performance. For receiver beamforming, the grating lobe receives interference from other directions, causing false targets and affecting the determination of target positions. Therefore, it is necessary to suppress the grating lobe phenomenon in beamforming. First, the position of the grating lobe is determined based on the relationship between the beamforming main lobe angle and the phase of the antenna radiated signal:

[0102]

[0103] Where Φ is the antenna radiation phase delay, d is the distance between antenna elements, θ is the main lobe angle, and λ is the wavelength of the transmitted / received signal. The beam angle can be calculated by solving the phase shift function.

[0104]

[0105] The arcsin function can only produce real solutions within the range of -1 to +1; no real solutions can be obtained outside this range. Utilizing phase periodicity, it repeats with a period of 2π, so (m×2π+ΔΦ) can be used instead of ΔΦ. Furthermore, to avoid aiming for a single real solution from the grating lobes, it can be written as:

[0106]

[0107] Here, m takes the values ​​m = 0, ±1, ±2L. If we want there to be only one m that satisfies the above requirement, that is, for all cases |m|≥1, arcsin>1, then we can solve for d≤λ / 2.

[0108] However, the distance between receiving antennas is not always better the smaller it is. When the distance between receiving antennas is too close, coupling effects will occur, which will directly affect the matching performance of the antennas and limit their radiation capability. Therefore, the spacing between the antennas should be increased as much as possible within a reasonable range. Thus, the final spacing between the receiving antennas is set to λ / 2.

[0109] After implementing pattern grating lobe suppression and antenna coupling suppression, it is also necessary to suppress the direct wave from the transmitting antenna to the receiving antenna by considering the antenna's polarization direction. Typically, the polarization direction of a multi-channel ground-penetrating radar is set along the direction of motion, such as... Figure 3 As shown, however, if this polarization direction is used in this invention, there will be signals directly radiated from the transmitting antenna to the receiving antenna. However, due to the significant differences in the relative positions of the transmitting antenna and the multiple receiving antennas, it is difficult to ensure that each receiving antenna receives the same level of direct wave signal. Furthermore, the differences in direct wave signals are difficult to quantify, making effective compensation and correction challenging. Therefore, in this solution, both the transmitting and receiving antennas are polarized perpendicular to the direction of motion, such as... Figure 4 As shown, this polarization method effectively reduces the signal directly reaching the receiving antenna from the transmitting antenna, effectively suppresses the intensity of the direct wave, and ensures good consistency across the four channels. Furthermore, using polarization perpendicular to the direction of motion allows for the acquisition of more lateral target details. Combined with beamforming processing methods, this effectively improves the detection accuracy in the lateral direction.

[0110] This embodiment proposes an antenna layout method for beamforming at the receiver of a ground-penetrating radar (GPR). This method addresses the problems of time lag in channel data and difficulties in beamforming when using traditional multi-channel GPR schemes, which prevent the full utilization of the array antenna's potential. It introduces a new approach, designing the antenna array based on beamforming theory. One antenna transmits the signal, while four receiving antennas, each equipped with an independent ADC, synchronously acquire the signal, ensuring good signal time consistency. This array layout meets the requirements for data processing using beamforming methods. The integrated processing of four-channel data by beamforming improves the detection range and resolution performance of the GPR.

[0111] This embodiment proposes an antenna layout method for beamforming at a ground-penetrating radar receiver. In the receiver antenna array layout design, the influence of the antenna element spacing on the grating lobe performance of the radiation pattern and the coupling between antenna elements is considered. This consideration not only effectively avoids false targets appearing after data processing using beamforming methods, but also effectively improves the main lobe gain of the equivalent radiation pattern, thereby significantly improving the signal-to-noise ratio of the received signal.

[0112] This embodiment proposes an antenna layout method for beamforming at the receiver of a ground-penetrating radar (GPR), employing a different lateral polarization direction than traditional multi-channel GPRs. This polarization effectively reduces the signal directly reaching the receiver from the transmitting antenna, suppresses the intensity of the direct wave, ensures good consistency across the four channels, and significantly improves the accuracy of the acquired data.

[0113] It should be noted that the methods and detailed examples provided in the above embodiments can be incorporated into the apparatus and devices provided in the embodiments, and can be referred to each other, without further elaboration.

[0114] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0115] In the embodiments provided in this application, it should be understood that the disclosed apparatus / terminal devices and methods can be implemented in other ways. For example, the apparatus / device embodiments described above are merely illustrative. For instance, the division of the modules or units described above is merely a logical functional division, and in actual implementation, it can be divided in other ways. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0116] The technical solutions provided by the present invention have been described in further detail above with reference to the accompanying drawings in order to highlight their advantages and benefits, and are not intended to limit the present invention. Any modifications, combinations, improvements and equivalent substitutions of the present invention based on the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An antenna layout method for beamforming at a ground-penetrating radar receiver, characterized in that, The method includes: The form of the ground-penetrating radar antenna array is determined based on the beamforming requirements. Construct the equivalent radiation pattern of the antenna array layout based on the form of the radar antenna array; Suppress grating lobe phenomena in the equivalent radiation pattern of the antenna array layout; The coupling effect in the equivalent radiation pattern of the antenna array layout is suppressed; Based on the polarization direction of the antenna with the suppressed equivalent radiation pattern, the direct wave from the transmitting antenna to the receiving antenna is suppressed, and the antenna layout is completed. The process of determining the form of the ground-penetrating radar antenna array based on beamforming requirements includes: Four receiving antennas are arranged symmetrically along the vertical axis in a linear manner with equal spacing. The transmitting antenna is placed at the vertical axis; The transmitter adopts a single-channel structure and is connected to the signal source, while the receiver adopts a four-channel structure, with each channel equipped with an independent high-speed ADC. The equivalent radiation pattern for constructing the antenna array layout based on the form of the radar antenna array includes: Calculate the radiation pattern of each antenna element based on the position of the antenna elements in the ground-penetrating radar antenna array; The radiation patterns of each antenna element are superimposed to obtain the actual radiation pattern of the antenna array. The antenna array's actual radiation pattern is normalized to obtain the equivalent radiation pattern of the antenna array layout. The suppression of grating lobe phenomena in the equivalent radiation pattern of the antenna array layout includes: The beam angle can be calculated by solving the phase shift function; The beam angle is formed by periodically adjusting the phase. The position of the grating lobe is determined based on the relationship between the beamforming main lobe angle and the phase of the antenna radiated signal. Adjust the antenna array spacing according to the position of the grating lobes to suppress grating lobe formation; Suppressing coupling effects in the equivalent radiation pattern of the antenna array layout includes: setting the spacing of the receiving antennas to a certain value. ; Both the receiving and transmitting antennas employ polarization perpendicular to the direction of motion.

2. The antenna layout method for beamforming at a ground-penetrating radar receiver according to claim 1, characterized in that, The beam angle can be calculated by solving the phase shift function, specifically as follows: ， in, For antenna radiation phase delay, The distance between antenna elements. Main lobe angle, The wavelength of the transmitted / received signal.

3. The antenna layout method for beamforming at a ground-penetrating radar receiver according to claim 1, characterized in that, The determination of the grating lobe position based on the relationship between the beamforming main lobe angle and the phase of the antenna radiated signal specifically involves: ， Where m = 0, ±1, ±2… 4. An antenna layout system for beamforming at a ground-penetrating radar receiver, characterized in that, The system is implemented based on the method according to any one of claims 1 to 3, and the system comprises: The radar antenna array determination unit is used to determine the form of the ground-penetrating radar antenna array according to the beamforming requirements. Equivalent radiation pattern construction unit, used to construct the equivalent radiation pattern of the antenna array layout according to the form of the radar antenna array; A grating lobe suppression unit is used to suppress grating lobe phenomena in the equivalent radiation pattern of the antenna array layout; A coupling suppression unit is used to suppress coupling effects in the equivalent radiation pattern of the antenna array layout; The direct wave suppression unit is used to suppress the direct wave from the transmitting antenna to the receiving antenna according to the polarization direction of the antenna in the suppressed equivalent radiation pattern, thus completing the antenna layout.

5. A computer-readable storage medium, characterized in that, The computer-readable storage medium is used to store a computer program that executes an antenna layout method for beamforming at a ground-penetrating radar receiver as described in any one of claims 1-3.

6. A computer device, characterized in that, It includes a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program stored in the memory, the processor executes an antenna layout method for beamforming at a ground-penetrating radar receiver according to any one of claims 1-3.

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