Bridge deformation monitoring side-looking device and bridge dynamic precise deformation measurement method

Abstract

The application discloses a bridge deformation monitoring side-looking device and a bridge dynamic precise deformation measurement method, and relates to the technical field of remote sensing. The device comprises a radar antenna, a rotatable antenna transverse support connected with the radar antenna, a surveying and mapping base fixedly connected with the antenna transverse support, and a data acquisition module in communication connection with the radar antenna. The antenna transverse support is provided with a rotating mechanism, and the rotating mechanism is used for rotating to adjust the angle of the radar antenna. In this way, the angle corresponding to the radar antenna can be adjusted through the rotating mechanism, so that the monitorable direction can be adjusted, and the flexibility of bridge deformation monitoring is improved.

Description

Technical Field

[0001] This application relates to the field of remote sensing technology, and in particular to a bridge deformation monitoring side-view device and a method for measuring bridge dynamic precision deformation. Background Technology

[0002] With the development of science and technology and the socio-economic progress, the number of bridges is increasing. During their use, bridges may deform due to various reasons, and this deformation can pose risks to their operation. Therefore, deformation monitoring of bridges is necessary.

[0003] Existing technologies monitor bridge deformation using measuring devices, which typically include fixed radar antennas. These antennas perform ground-based radar interferometry to determine the bridge's deformation. The problem with this technology is that the fixed radar antenna position limits its monitoring to a single vertical target in front of the radar, making it impossible to monitor deformation in other directions (e.g., laterally). This limitation hinders the flexibility of bridge deformation monitoring.

[0004] Therefore, the relevant technologies still need to be improved and developed. Summary of the Invention

[0005] The main objective of this application is to provide a bridge deformation monitoring side-view device and a method for measuring bridge dynamic precision deformation, aiming to solve the technical problem that the fixed position of the radar antenna of the measuring device in related technologies is not conducive to improving the flexibility of bridge deformation monitoring.

[0006] To achieve the above objectives, the first aspect of this application provides a bridge deformation monitoring side-viewing device, wherein the device includes:

[0007] A radar antenna, a rotatable antenna horizontal support connected to the radar antenna, a mapping base fixedly connected to the antenna horizontal support, and a data acquisition module communicatively connected to the radar antenna;

[0008] The antenna's horizontal support is equipped with a rotating mechanism, which is used to rotate to adjust the angle of the radar antenna.

[0009] Specifically, the aforementioned antenna horizontal support is also equipped with antenna connectors and support brackets;

[0010] The aforementioned rotating mechanism includes a horizontally arranged inner rod and an outer rod, with the outer rod rotatably connected to the inner rod.

[0011] The radar antenna is connected to the outer rod of the rotating mechanism via the antenna connector.

[0012] Specifically, the two ends of the inner rod of the aforementioned rotating mechanism are respectively connected to a support bracket;

[0013] Each of the aforementioned support brackets is connected to a surveying base.

[0014] Specifically, the aforementioned radar antenna includes one transmitting antenna and two receiving antennas;

[0015] The aforementioned data acquisition module includes a radio frequency unit, a GPS receiving antenna, and a computing unit.

[0016] Specifically, a slope gauge is installed on the outer rod of the aforementioned rotating mechanism;

[0017] The outer rod of the aforementioned rotating mechanism can be rotated and fixed by a fixing mechanism to adjust the elevation angle of the aforementioned radar antenna;

[0018] The aforementioned slope gauge is used to indicate the elevation angle of the aforementioned radar antenna.

[0019] Specifically, the aforementioned surveying base includes a surveying tripod, a retractable horizontal angle adjustment mechanism mounted on the surveying tripod, and a support bracket connected to the horizontal angle adjustment mechanism.

[0020] The horizontal angle adjustment mechanism on each of the above-mentioned surveying bases can extend and retract in the vertical direction to adjust the horizontal angle of the above-mentioned rotation mechanism;

[0021] The inner rod of the aforementioned rotating mechanism is connected to the aforementioned support bracket.

[0022] Specifically, the two ends of the aforementioned rotating mechanism are also provided with laser emitter fixing grooves for fixing the laser emitter;

[0023] The aforementioned laser emitter is used to emit laser light to indicate the current monitoring location.

[0024] Specifically, the line connecting the geometric centers of the aforementioned radar antennas is parallel to the aforementioned rotating mechanism.

[0025] A second aspect of this application provides a method for measuring the dynamic precision deformation of a bridge, wherein the method is applied to any of the aforementioned bridge deformation monitoring side-viewing devices, and the method includes:

[0026] Initial radar data is acquired through the radar antenna, and single-view complex images are generated based on the initial radar data.

[0027] An interferogram is generated based on the above single-view complex image;

[0028] Differential interferometry processing is performed on the above interferogram to obtain a differential interferogram containing the deformed phase;

[0029] The phase unwrapping process is performed on the above differential interferogram to obtain the unwrapped true phase;

[0030] The target deformation is calculated based on the true phase and the radar wavelength of the radar antenna.

[0031] Specifically, the above-mentioned generation of single-view complex images based on the aforementioned radar initial data includes:

[0032] The radar initial data above is corrected for antenna squint variation and extracted for azimuth echo to obtain radar echo signal;

[0033] The radar echo signal is subjected to range focusing processing to obtain a range signal, and the single-view complex image is generated based on the range signal.

[0034] As can be seen from the above, the present application provides a bridge deformation monitoring side-viewing device, which includes: a radar antenna, a rotatable antenna horizontal support connected to the radar antenna, a surveying base fixedly connected to the antenna horizontal support, and a data acquisition module communicatively connected to the radar antenna; wherein, the antenna horizontal support is provided with a rotation mechanism, which is used to rotate to adjust the angle of the radar antenna.

[0035] Compared with existing technologies, the bridge deformation monitoring side-viewing device provided in this application is equipped with an antenna transverse support, which has a rotating mechanism for rotating to adjust the angle of the radar antenna. This allows for adjustment of the radar antenna's angle, thereby adjusting the monitored direction and improving the flexibility of bridge deformation monitoring. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a structural schematic diagram of a bridge deformation monitoring side-viewing device provided in an embodiment of this application;

[0038] Figure 2 This is a schematic flowchart illustrating a method for measuring the dynamic and precise deformation of a bridge, as provided in an embodiment of this application.

[0039] Figure 3 This is a schematic diagram of the data processing flow in a bridge dynamic precision deformation measurement method provided in an embodiment of this application;

[0040] Figure 4 This is a schematic diagram illustrating a usage scenario of a bridge deformation monitoring side-viewing device provided in an embodiment of this application;

[0041] Figure 5 This is a schematic diagram of the real-time lateral linear deformation monitoring results of a bridge provided in an embodiment of this application;

[0042] The numbers in the diagram represent: radar antenna 1, antenna horizontal support 2, surveying base 3, data acquisition module 4, power supply 5; rotation mechanism 21, antenna connector 22; surveying tripod 31, horizontal angle adjustment mechanism 32, support bracket 33; radio frequency unit 41, calculation unit 42; inner rod 211, outer rod 212; slope ruler 2121. Detailed Implementation

[0043] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of this application with unnecessary detail.

[0044] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0045] It should also be understood that the terminology used in this application specification is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this application specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0046] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0047] As used in this specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to classification." Similarly, the phrases "if determined" or "if classified to [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once classified to [the described condition or event]," or "in response to classification to [the described condition or event]."

[0048] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0049] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0050] Currently, the number of bridges is increasing, and bridges may deform during their use. For example, many bridges are affected by various factors such as design defects, structural aging, environmental changes, and dynamic loads, which may lead to varying degrees of defects and problems, such as pier settlement, beam deflection, support displacement, and structural cracking. These defects and problems may lead to bridge operation safety accidents, resulting in loss of life and property.

[0051] In one application scenario, high-dynamic deformation monitoring technology for bridges can be used to monitor bridge structures at high frequencies exceeding 10Hz. The monitoring results reflect the deformation and vibration characteristics of the bridge, thereby further assessing the bridge's safe operation status and providing data support for safe bridge operation.

[0052] Ground-based radar interferometry is a novel microwave interferometric technique with advantages such as high precision, high temporal and spatial resolution, and flexible monitoring. It can use high frequencies to perform high-precision dynamic deformation monitoring of ground areas and targets, and this technology has been widely used for bridge dynamic deformation monitoring. Currently, commonly used ground-based radar methods for monitoring bridge dynamic deformation monitor the bridge beams from below. However, this method is susceptible to radar signal obstruction by bridge piers, making it difficult to monitor the dynamic deformation of the entire bridge. Furthermore, specular scattering of radar signals from smooth surfaces can lead to weak echo signals, resulting in monitoring errors. With the increasing demands for bridge deformation monitoring, there is a need to develop a method for monitoring the dynamic deformation of bridge beams with high temporal and spatial density.

[0053] Currently, the number of bridges being built is increasing rapidly. Along with this increasing number of bridges, safety accidents are also on the rise. Deformation characteristics can reflect the condition of bridge structures, and full-span bridge deformation monitoring allows for high-density time-based deformation monitoring of bridge beams, better identifying potential bridge hazards and enabling measures to be taken to prevent bridge accidents.

[0054] Ground-based radar is divided into two types: synthetic aperture ground-based radar (SAR) and real aperture ground-based radar (SAR). Each has its advantages in infrastructure deformation monitoring applications: SAR offers higher azimuth resolution through its synthetic aperture, while SAR offers greater monitoring flexibility based on different monitoring modes. However, both SAR and SAR have significant limitations in real-time deformation monitoring of long-span lateral structures. SAR is limited by its second-level monitoring frequency, making it difficult to perform high-dynamic real-time deformation monitoring; SAR is limited by monitoring performance and monitoring geometry, making it difficult to perform full-area lateral dynamic deformation monitoring of long-span lateral structures.

[0055] In existing technologies, measuring devices typically rely on radar antennas for bridge deformation monitoring. These devices use fixed radar antennas to perform ground-based radar interferometry to determine the bridge's deformation. The problem with this technology is that the fixed position and horizontal arrangement of the radar antennas limit monitoring to a single vertical target in front of the radar, hindering the monitoring of bridge deformation in other directions (e.g., laterally). This limits the flexibility of bridge deformation monitoring. Specifically, in one existing monitoring device, the monitoring surface is perpendicular to the radar antenna. This means the radar angle and direction are fixed, and the device can only monitor vertical targets in front of the radar, preventing monitoring of lateral structures like bridges from the side.

[0056] To address at least one of the aforementioned technical problems, this application provides a novel bridge deformation monitoring side-viewing device. The device includes: a radar antenna, a rotatable transverse support connected to the radar antenna, a mapping base fixedly connected to the transverse support, and a data acquisition module communicatively connected to the radar antenna. The transverse support is equipped with a rotation mechanism for rotating to adjust the angle of the radar antenna.

[0057] Compared with existing technologies, the bridge deformation monitoring side-viewing device provided in this application is equipped with an antenna transverse support, which has a rotating mechanism for rotating to adjust the angle of the radar antenna. This allows for adjustment of the radar antenna's direction and angle, thereby adjusting the monitorable direction and improving the flexibility of bridge deformation monitoring.

[0058] like Figure 1As shown in the figure, this application embodiment provides a bridge deformation monitoring side-view device. The device includes: a radar antenna 1, a rotatable antenna horizontal support 2 connected to the radar antenna 1, a surveying base 3 fixedly connected to the antenna horizontal support 2, and a data acquisition module 4 communicatively connected to the radar antenna 1; wherein, the antenna horizontal support 2 includes a rotation mechanism 21, which is used to rotate to adjust the angle of the radar antenna 1.

[0059] It should be noted that the bridge deformation monitoring side-viewing device provided in this application embodiment is a lateral bridge deformation monitoring side-viewing device, that is, it can be set on the side of the bridge to realize lateral monitoring of bridge deformation.

[0060] Specifically, the aforementioned antenna horizontal support 2 is also provided with an antenna connector 22; the aforementioned rotation mechanism 21 includes a horizontally arranged inner rod 211 and an outer rod 212, the aforementioned outer rod 212 being rotatably connected to the aforementioned inner rod 211; the aforementioned radar antenna 1 is connected to the aforementioned outer rod 212 of the aforementioned rotation mechanism 21 through the aforementioned antenna connector 22.

[0061] Specifically, the rotating mechanism 21 includes an inner rod 211 and an outer rod 212. The outer rod 212 is rotatably connected to the inner rod 211, and the radar antenna 1 is connected to the outer rod 212 via an antenna connector 22. The rotating mechanism 21 is arranged horizontally, while the radar antenna 1 is perpendicular to the rotating mechanism 21 and arranged vertically, rotating 90° compared to the horizontal arrangement in the prior art. Therefore, it can be used to monitor transverse structures. Simultaneously, the direction and angle of the radar antenna 1 can be adjusted by rotating the outer rod 212, thereby adjusting the monitorable direction and improving the flexibility of bridge deformation monitoring.

[0062] It should be noted that the bridge deformation monitoring side-view device provided in this application is a lateral monitoring device based on GAMMA GPRIII ground-based interferometric radar.

[0063] In the embodiments of this application, such as Figure 1 As shown, radar antenna 1 includes one transmitting antenna and two receiving antennas, but the specific number of antennas can be set and adjusted according to actual needs, and is not specifically limited here.

[0064] Furthermore, the aforementioned surveying base 3 includes a surveying tripod 31, a retractable horizontal angle adjustment mechanism 32 disposed on the surveying tripod, and a support 33 connected to the horizontal angle adjustment mechanism 32; the horizontal angle adjustment mechanisms 32 on each of the aforementioned surveying bases 3 can extend and retract in the vertical direction to adjust the horizontal angle of the aforementioned rotating mechanism 21; the inner rod 211 of the aforementioned rotating mechanism 21 is connected to the aforementioned support 33.

[0065] The antenna horizontal support 2 is made of aluminum alloy, and its main structure includes a rotating mechanism 21 and an antenna connector 22. The three radar antennas 1 are connected to the rotating mechanism 21 via the antenna connector 22. Figure 1 As shown, the two ends of the inner rod 211 of the aforementioned rotating mechanism 21 are respectively connected to a support 33; that is, this application provides two support 33s and two surveying bases 3. In a specific application scenario, the aforementioned rotating structure 21 can be a support crossbar.

[0066] Furthermore, a slope gauge 2121 is provided on the outer rod 212 of the aforementioned rotating mechanism 21; the outer rod 212 of the aforementioned rotating mechanism 21 can be rotated and fixed by a fixing mechanism ( Figure 1 (Not shown) is fixed to adjust the elevation angle of the radar antenna 1; the slope ruler 2121 is used to indicate the elevation angle of the radar antenna. In this embodiment, the fixing mechanism is a locking screw. In actual application, other detachable locking mechanisms can also be used, which are not specifically limited here.

[0067] Specifically, the elevation angle of radar antenna 1 can be adjusted by adjusting the angle of the outer rod 212 of the rotating mechanism 21. The inner rod 211 of the rotating mechanism 21 is fixedly connected to the support 33, and the outer rod 212 of the rotating mechanism 21 is connected to radar antenna 1 through antenna connector 22. The antenna elevation angle is adjusted by rotating the outer rod 212 of the rotating mechanism 21. The current elevation angle of the antenna can be read by checking the slope gauge 2121 on the rotating mechanism 21. The elevation angle of radar antenna 1 is fixed by tightening the screws on the rotating mechanism 21.

[0068] The horizontal angle of the rotating mechanism 21 can be adjusted via the horizontal angle adjustment mechanism 32 connected to the bottom of the support 33. The horizontal angle adjustment mechanism 32 can adjust the height of the two support 33s respectively, thereby changing the horizontal angle of the rotating mechanism 21; this can be achieved by checking the level on the rotating mechanism 21. Figure 1 (Not shown in the image), the current horizontal angle of the rotating mechanism 21 can be read.

[0069] It should be noted that, in one application scenario, in addition to its vertical extension and retraction function, the horizontal angle adjustment mechanism 32 can also move horizontally, thereby changing the angle between the rotating mechanism 21 and the monitoring target, and realizing more flexible terrain deformation monitoring.

[0070] Furthermore, laser emitter fixing grooves are also provided at both ends of the aforementioned rotating mechanism 21. Figure 1 (Not shown in the image), used to fix the laser emitter ( Figure 1 (Not shown in the image); the laser emitter described above is used to emit laser light to indicate the current monitoring location. This allows monitoring personnel to quickly determine the current monitoring location and adjust it more conveniently and flexibly.

[0071] In one application scenario, a ground-based interferometric radar GPS unit is also installed at the center of the aforementioned rotating mechanism 21. Figure 1 (Not shown in the image), used for location positioning by ground-based interferometric radar.

[0072] In this embodiment, the geometric center line of the radar antenna 1 is parallel to the rotating mechanism 21. The transverse rotating mechanism 21 connected to the radar antenna 1 is designed to take into account the impact of changes in the elevation angle of the radar antenna 1 on the antenna baseline. The design of the geometric center line of the radar antenna 1 being parallel to the rotating mechanism 21 ensures that changes in the elevation angle of the radar antenna 1 do not alter the antenna baseline, thus improving monitoring accuracy.

[0073] Furthermore, the aforementioned data acquisition module 4 includes a radio frequency unit 41 and a GPS receiving antenna ( Figure 1 (Not shown in the diagram) and calculation unit 42. The calculation unit 42 is used to process and calculate the collected data to obtain the measured bridge deformation. The GPS receiving antenna can be set at the center of the rotating mechanism 21 to acquire location information, time information (e.g., Coordinated Universal Time), etc. The radar antenna 1 has an interface that is directly connected to the radio frequency unit 41. The function of the radio frequency unit is to generate linear frequency modulated chirp signals and obtain range-direction compressed echoes.

[0074] In the embodiments of this application, such as Figure 1 As shown, the aforementioned bridge deformation monitoring side-viewing device also includes a power supply 5. In a specific application scenario, the power supply 5 includes a transformer ( Figure 1 (not shown in the image) and mobile power bank ( Figure 1 (not shown in the text), but not as a specific limitation.

[0075] As can be seen from the above, in this application, the bridge deformation monitoring side-viewing device is equipped with an antenna transverse support 2, which has a rotating mechanism 21. The rotating mechanism 21 includes an inner rod 211 and an outer rod 212, with the outer rod 212 rotatably connected to the inner rod 211. The radar antenna 1 is connected to the outer rod 212 via an antenna connector 22. Thus, the direction and angle of the radar antenna 1 can be adjusted by rotating the outer rod 212, thereby adjusting the monitorable direction and improving the flexibility of bridge deformation monitoring.

[0076] like Figure 2 As shown, corresponding to the aforementioned bridge deformation monitoring side-viewing device, this application embodiment also provides a method for measuring bridge dynamic precision deformation. This method is applied to any of the aforementioned bridge deformation monitoring side-viewing devices, and includes the following steps:

[0077] Step S100: Acquire initial radar data through the radar antenna, and generate single-view complex images based on the initial radar data.

[0078] Step S200: Generate an interferogram based on the above single-view complex image;

[0079] Step S300: Perform differential interferometry processing on the above interferogram to obtain a differential interferogram containing the deformed phase;

[0080] Step S400: Perform phase unwrapping processing on the above differential interferogram to obtain the unwrapped true phase;

[0081] Step S500: Calculate the target deformation based on the true phase and the radar wavelength of the radar antenna.

[0082] Specifically, the above-mentioned generation of single-view complex images based on the aforementioned radar initial data includes:

[0083] The radar initial data above is corrected for antenna squint variation and extracted for azimuth echo to obtain radar echo signal;

[0084] The radar echo signal is subjected to range focusing processing to obtain a range signal, and the single-view complex image is generated based on the range signal.

[0085] Figure 3 This is a schematic diagram of the data processing flow in a bridge dynamic precision deformation measurement method provided in an embodiment of this application, as shown below. Figure 3 As shown, for the initial data collected, an interferogram is generated, and coherence estimation, masking, phase unwrapping, interpolation and other processing are performed to finally calculate the deformation.

[0086] In order to obtain information on the deformation monitoring of lateral structures by ground-based interferometric radar, this application uses a data processing method. The process of this method is as follows: Single Look Complex (SLC) image generation, interferogram generation, coherence estimation, masking, phase unwrapping, and deformation extraction.

[0087] The radar initial data (Raw data) includes SLC files and SLC parameter files. Each SLC image represents a single-view complex image, and each SLC data contains the amplitude and phase information of the monitored object. When the monitored object deforms between two observation times, the corresponding phase changes. By interfering pairwise SLC images, corresponding interferometric images are obtained, and the phase difference between the images is obtained. After a series of processing steps, including atmospheric phase removal and unwrapping, the relationship between deformation and phase can be obtained, and the deformation can be calculated.

[0088] It should be noted that, Figure 3The document provides various data formats and names, such as "interference plot.ati" and "coherence plot.cc". The data formats and names used in actual application scenarios can be set and adjusted according to actual needs, and no specific restrictions are made here.

[0089] The raw data from the ground-based radar undergoes azimuth echo extraction, antenna squint correction, and range focusing to obtain the corresponding single-view complex image. Pairwise interferometry is performed between the SLC images to obtain the corresponding interferometric image. The two SLC images from the ground-based radar can be represented as follows: Where |u| is the modulus of the complex number, φ is the phase angle, and j is the imaginary unit. The conjugate multiplication of corresponding pixels in the two images is shown in the following formula (1):

[0090]

[0091] The interference phase is then shown in formula (2):

[0092]

[0093] The deformation measurement principle of the GAMMA GPRI II ground-based interferometric radar is similar to that of the spaceborne interferometric radar. However, it is set at a fixed position during data acquisition, so the spatial baseline of the same antenna is zero, no registration is required, and the generated interferogram does not have a flat phase or an elevation phase. Therefore, the interferometric phase at a certain moment is as shown in the following formula (3):

[0094] φ int =φ def +φ atmo +φ noise (3);

[0095] Where, φ int For the interference phase; φ def For deformation phase; φ noise For noise phase; φ atmo This refers to the atmospheric phase.

[0096] Coherence reflects the degree of similarity between signals and is commonly used to measure the signal quality at interferogram points. The coherence γ of complex signals u1 and u2 is shown in the following formula (4):

[0097]

[0098] Here, γ represents coherence, with a value between 0 and 1. Coherence reflects the similarity or correlation between two complex images. Coherence is usually quantified by calculating the coherence coefficient. The coherence coefficient is a value between 0 and 1, representing the degree of similarity between signals.

[0099] For radar interferometry processing, calculating the interferometric phase is a crucial step. The interferometric phase encompasses the change in distance to the target point between two observations. The interferogram is obtained by conjugate multiplication of two SLC (Special Radar Capture) images. These two SLC images are typically obtained by observing the same target area at different times. The interference fringes in the interferogram reflect the path difference of the signal between the two observations, i.e., the change in the interferometric phase. Therefore, calculating the interferometric phase is essentially extracting this fringe information from the interferogram and converting it into a phase value. The interferometric phase includes deformation phase, noise phase, and atmospheric phase. The interference fringes in the interferogram reflect the path difference of the signal between the two observations, i.e., the change in the interferometric phase. Therefore, calculating the interferometric phase is essentially extracting this fringe information from the interferogram and converting it into a phase value.

[0100] In one application scenario, masking can be performed. The purpose of masking is to remove points with poor signal quality in the interferogram, avoiding phase jumps caused by signal noise, which could lead to unwrapping errors and affect deformation monitoring results. For example, points with coherence less than 0.3 can be removed from the interferogram, leaving points with better coherence.

[0101] Further, phase unwrapping is performed. This involves removing the deformation and noise phase from the interference phase, restoring the deformed phase from its principal value or phase difference to its true value. The interference fringes in the interferogram reflect the changes in the interference phase between two observations. After extracting the interference fringe information, it needs to be converted into phase values. This process requires phase unwrapping to recover the true continuous phase information.

[0102] Phase unwrapping is the process of restoring the phase from the principal value or phase difference value to the true value. Since the phase can only be measured within the range of [-π, π], when the true phase exceeds this range, phase ambiguity will occur, as shown in the following formula (5):

[0103]

[0104] in, Let φ be the unwrapped phase, unwrap{} be the unwrapping operator, and n be the ambiguity, i.e., the number of wrapping cycles. Phase unwrapping is the process of restoring a wrapped phase within the range [-π, π] to an unwrapped phase. Phase unwrapping is a crucial step in ground-based interferometric radar's lateral linear deformation monitoring method. Unwrapping errors can lead to phase jumps, resulting in deformation information errors. The quality of phase unwrapping significantly impacts the accuracy of deformation monitoring. n is a constant; the value of n for each pixel in the interferogram may differ. Taking a certain point as a reference point, the value of n at point i depends on how many 2π cycles the phase changes during the transition from that point to the reference point.

[0105] The interference fringes in the interferogram reflect the change in the interference phase between two observations. After extracting the interference fringe information, it needs to be converted into phase values. This process requires phase unwrapping to recover the true continuous phase information.

[0106] In deformation monitoring of transverse structures such as bridges, phase unwrapping methods based on path tracing have certain limitations. Due to their long length and large mass, the deformation caused by trains crossing bridges may generate deformation signals exceeding 2π periods across the entire bridge. This manifests as a dense band of interference fringes diagonally across the interferogram in the real-time deformation monitoring results of ground-based interferometric radar. This band can cause errors in the phase unwrapping method based on path tracing, and the resulting errors will affect the deformation monitoring results.

[0107] To address the phase unwrapping problem caused by the aforementioned reasons, a phase unwrapping error correction method based on a two-step unwrapping method and Kalman filtering is proposed. In this embodiment, considering the presence of diagonally spanning interference fringe stripes, the two-step unwrapping method suitable for lateral monitoring first uses Kalman filtering for adaptive noise correction; then, by manually selecting a phase unwrapping reference point, one-dimensional phase unwrapping is performed in the spatial domain; finally, one-dimensional phase unwrapping is performed in the time domain, thus obtaining a better phase unwrapping result than the path tracing method.

[0108] Kalman filtering consists of two iterative steps: a prediction process and an estimation process. The prediction process is shown in equations (6) and (7) below:

[0109]

[0110] Where, x k P is the deformation estimate at the k-th iteration; A is the recursion matrix; P k Let be the covariance at the k-th iteration. The Kalman filter estimation process is shown in equations (8) to (10) below:

[0111]

[0112] Where, x k P is the deformation estimate at the k-th iteration; A is the recursion matrix; P k Let be the covariance at the k-th iteration. The Kalman filter estimation process is shown in equations (11) to (13) below:

[0113]

[0114]

[0115] Among them, K k Z represents the Kalman gain at the k-th iteration. A larger Kalman gain indicates greater confidence in the observed values, and vice versa.k The deformation observation value is given at the k-th iteration. Kalman filtering adjusts the filtering degree by setting different values ​​for Q and R: over-filtering results in loss of deformation information, while under-filtering leads to excessive noise. Through multiple iterations, a noise-reduced interferogram is obtained after Kalman filtering. Q and R represent the process noise covariance matrix and the observation noise covariance matrix, respectively. The specific values ​​of Q and R are preset according to actual needs to control the filtering degree, H = [1 0].

[0116] Specifically, in this embodiment, Kalman filtering is performed on the unwrapped interferogram. The iterative process is carried out according to formulas (6) to (10), and the iteration amount is x. k and P k , For input, x k This is the output after Kalman filtering. The observed value is the numerical value obtained from radar observation, and the predicted value is the result obtained after Kalman filtering. The purpose of Kalman filtering is to remove noise. Thus, an unwrapped interferogram is obtained by unwrapping the interferogram, and the unwrapped interferogram can be converted into a deformation.

[0117] After phase unwrapping, deformation information extraction is required, i.e., deformation calculation. After obtaining the interferogram, there is a "half-wavelength" relationship between phase and deformation, i.e., one full-cycle fringe corresponds to half the radar signal wavelength of the ground radar line of sight. After phase unwrapping, the relative deformation between each pixel can be obtained. A high coherence point needs to be selected as a reference point in the undeformed region to recover the absolute deformation value corresponding to each pixel in the interferogram. The deformation extraction formula for the transverse structure of the ground interferometric radar is shown in the following formula (14):

[0118]

[0119] Where D is the deformation; λ is the radar wavelength; This is the untangling phase.

[0120] In the interferogram, the unvarnished region appears as a region with clear, continuous phase fringes and no obvious noise. The composition of the ground-based radar interferometric phase is shown in formula (3) above. In the unvarnished region, the interferometric phase of the pixel points contains φ... def =0, so it can be expressed as the following formula (15):

[0121] φ int =φ atmo +φ noise (15);

[0122] By performing a difference process on formulas (3) and (15), the interference phase only includes the deformation phase. The deformation is then solved using the relationship between the phase and the displacement. In the embodiments of this application, the change in displacement at two different times is the deformation value to be obtained.

[0123] Thus, a bridge deformation monitoring side-viewing device and a method for measuring the dynamic and precise deformation of bridges are provided for high-dynamic real-time deformation monitoring of the entire bridge. This method is applied to the bridge deformation monitoring side-viewing device provided in this embodiment. The device includes an antenna transverse support with a rotating mechanism comprising an inner rod and an outer rod. The outer rod is rotatably connected to the inner rod, and the radar antenna is connected to the outer rod via an antenna connector. This allows adjustment of the radar antenna's direction and angle by rotating the outer rod, thereby adjusting the monitored direction and improving the flexibility of bridge deformation monitoring. Furthermore, this method introduces an optimized two-step unwrapping method and Kalman filtering based on the original ground-based interferometric radar deformation measurement method to correct the influence of high-dynamic real-time deformation on phase unwrapping, thereby improving the accuracy of the deformation results. This scheme expands the ground-based radar bridge deformation monitoring mode and its application scope, realizing ground-based interferometric radar monitoring of the dynamic deformation of transverse structures.

[0124] Figure 4 This is a schematic diagram illustrating a usage scenario of a bridge deformation monitoring side-viewing device provided in an embodiment of this application, such as... Figure 4 As shown in the embodiments of this application, deformation monitoring can be performed from the side of the bridge, and linear real-time deformation monitoring of long-span transverse structures can be realized.

[0125] Figure 5 This is a schematic diagram of the real-time lateral linear deformation monitoring results of a bridge provided in an embodiment of this application. Figure 5 In the diagram, part a represents interference, part b represents vertical deformation, part c represents the bridge deck deformation distribution at the moment of maximum deformation, and part d represents the deformation time series at the location of maximum deformation. For example... Figure 5 As shown, based on the solution of this application, bridge deformation can be monitored in real time, thereby improving the safety of bridge use.

[0126] It should be noted that the specific steps of data acquisition in the bridge dynamic precision deformation measurement method in this application embodiment can be mutually referred to with the specific functions of each component of the bridge deformation monitoring side-view device, and will not be repeated here.

[0127] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0128] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the above device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above device can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0129] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0130] 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.

[0131] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions are not in essence a departure from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A side-viewing device for monitoring bridge deformation, characterized in that, The device includes: A radar antenna arranged vertically, a rotatable antenna horizontal support connected to the radar antenna, a surveying base fixedly connected to the antenna horizontal support, and a data acquisition module communicatively connected to the radar antenna. The radar antenna includes one transmitting antenna and two receiving antennas. The antenna's transverse support is equipped with a rotating mechanism, which is used to rotate to adjust the angle of the radar antenna. The antenna horizontal support is also provided with an antenna connector; the rotation mechanism includes a horizontally arranged inner rod and an outer rod, the outer rod being rotatably connected to the inner rod; the radar antenna is connected to the outer rod of the rotation mechanism through the antenna connector; The inner rod of the rotating mechanism is connected to a support bracket at both ends; each support bracket is connected to a surveying base. The surveying base includes a surveying tripod, a retractable horizontal angle adjustment mechanism mounted on the surveying tripod, and a support connected to the horizontal angle adjustment mechanism; the horizontal angle adjustment mechanisms on each of the surveying bases can extend and retract in the vertical direction to adjust the horizontal angle of the rotation mechanism; the inner rod of the rotation mechanism is connected to the support. The line connecting the geometric centers of the radar antenna is parallel to the rotating mechanism.

2. The bridge deformation monitoring side-viewing device according to claim 1, characterized in that, The data acquisition module includes a radio frequency unit, a GPS receiving antenna, and a computing unit.

3. The bridge deformation monitoring side-viewing device according to claim 1, characterized in that, A slope gauge is provided on the outer rod of the rotating mechanism; The outer rod of the rotating mechanism can be rotated and fixed by a fixing mechanism to adjust the elevation angle of the radar antenna; The slope ruler is used to indicate the elevation angle of the radar antenna.

4. The bridge deformation monitoring side-viewing device according to claim 1, characterized in that, The rotating mechanism is also provided with laser emitter fixing grooves at both ends for fixing the laser emitter. The laser emitter is used to emit a laser to indicate the current monitoring location.

5. A method for measuring the dynamic precision deformation of a bridge, characterized in that, The method is applied to the bridge deformation monitoring side-viewing device according to any one of claims 1 to 4, and the method includes: Initial radar data is acquired through a radar antenna, and a single-view complex image is generated based on the initial radar data. An interferogram is generated based on the single-view complex image; Differential interferometry is performed on the interferogram to obtain a differential interferogram containing the deformed phase; The differential interferogram is subjected to phase unwrapping to obtain the unwrapped true phase; The target deformation is calculated based on the true phase and the radar wavelength of the radar antenna.

6. The method for measuring the dynamic precision deformation of bridges according to claim 5, characterized in that, The step of generating a single-view complex image based on the initial radar data includes: The initial radar data is corrected for antenna squint variation and azimuth echo is extracted to obtain radar echo signals. The radar echo signal is subjected to range focusing processing to obtain a range signal, and the single-view complex image is generated based on the range signal.

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