A three-dimensional imaging radar system and method for differential interferometric deformation monitoring

Abstract

The application discloses a three-dimensional imaging radar system and method for differential interference deformation monitoring, relates to the field of radar imaging, and comprises a radar host, a horizontal linear guide rail, a MIMO antenna array and a data processing and control unit; in the process of controlled movement of the MIMO antenna array on the horizontal linear guide rail, digital beam scanning perpendicular to the guide rail direction is carried out at each position of the guide rail; for each beam scanned by the MIMO antenna array, synthetic aperture imaging is carried out along the horizontal linear guide rail, and three-dimensional imaging of a measured target is obtained; each pixel in adjacent time three-dimensional imaging is subjected to continuous differential interference respectively, and deformation of each pixel point is obtained. The application can shorten three-dimensional imaging time, improve monitoring frequency, provide extremely high phase fidelity for differential interference, meet the demand of high-frequency dynamic monitoring, and essentially improve the reliability of monitoring results.

Description

Technical Field

[0001] This application relates to the field of radar imaging, and in particular to a three-dimensional imaging radar system and method for differential interferometric deformation monitoring. Background Technology

[0002] In the field of geological disaster monitoring (such as slope landslides and dam instability), radar technology is widely used due to its all-weather, non-contact, and high-precision characteristics. Differential interferometric radar technology is the core means to achieve sub-millimeter-level micro-deformation monitoring.

[0003] Existing technologies face the following main dilemmas when acquiring 3D images for deformation monitoring:

[0004] (1) Real aperture two-dimensional mechanical scanning radar: Although it can acquire real three-dimensional images, its core relies on two-dimensional (azimuth, elevation) servo mechanical scanning, resulting in low imaging efficiency. A single scan takes tens of minutes or even hours, which cannot meet the needs of high-frequency dynamic monitoring. At the same time, its complex precision mechanical structure has a high failure rate and low reliability when operating in the field for a long time.

[0005] (2) Synthetic Aperture Radar (SAR) schemes: Existing SAR is usually two-dimensional imaging (range and azimuth). When the two-dimensional image detected by the radar is projected onto the three-dimensional DEM model by combining it with an external Digital Elevation Model (DEM), local deviations or errors inevitably occur. (3) ArcSAR+MIMO array combination scheme: ArcSAR has inherent defects such as low computational efficiency and uneven image quality. The three-dimensional model generated by this combination scheme itself has problems such as uneven resolution and geometric distortion. When the line-of-sight deformation measured by differential interferometry is assigned to this inaccurate three-dimensional model, it will lead to inaccurate deformation positioning and error accumulation, which will seriously affect the accuracy and reliability of the monitoring results. MIMO stands for Multiple-Input Multiple-Output.

[0006] Therefore, there is an urgent need in this field for a new technical solution that can quickly generate high-fidelity 3D models and perform high-precision deformation monitoring on these models. Summary of the Invention

[0007] To address the aforementioned problems in the existing technology, this application provides a three-dimensional imaging radar system and method for differential interferometric deformation monitoring.

[0008] To achieve the above objectives, this application provides the following solution:

[0009] In a first aspect, this application provides a three-dimensional imaging radar system for differential interferometric deformation monitoring, comprising: a radar host, a horizontal linear guide rail, a MIMO antenna array, and a data processing and control unit;

[0010] The MIMO antenna array is moved in a controlled manner on the horizontal linear guide rail; the MIMO antenna array is electrically connected to the radio frequency front end of the radar host, and the MIMO antenna array is perpendicular to the horizontal linear guide rail; the data processing and control unit is connected to the radar host via data lines and control lines;

[0011] The MIMO antenna array performs a uniform linear scan along the horizontal linear guide rail. During the controlled movement of the MIMO antenna array on the horizontal linear guide rail, it performs digital beam scanning perpendicular to the guide rail direction at various positions on the guide rail. The data processing and control unit performs synthetic aperture imaging along the horizontal linear guide rail for each beam obtained by the MIMO antenna array to obtain a three-dimensional image of the target under test, and performs continuous differential interference on each pixel in the three-dimensional image of adjacent time to obtain the deformation of each pixel.

[0012] Optionally, the MIMO antenna array is mechanically coupled to the horizontal linear guide rail via a sliding device.

[0013] Optionally, the MIMO antenna array includes: multiple transmitting antenna units and multiple receiving antenna units corresponding to the transmitting antenna units; the multiple transmitting antenna units and the multiple receiving antenna units are used to realize electronic beam scanning perpendicular to the horizontal linear guide rail.

[0014] Optionally, the radar host is configured to include radio frequency and digital circuit modules for transmitting, receiving, and processing radar signals.

[0015] Secondly, this application provides a three-dimensional imaging radar method for differential interferometric deformation monitoring, comprising:

[0016] Using a MIMO antenna array, digital beam scanning is performed at each position on a horizontal linear guide rail to obtain target echoes with multiple different elevation beams.

[0017] Based on the target echo of each elevation beam scanned by the MIMO antenna array, synthetic aperture imaging is performed along a horizontal linear guide rail to obtain an image at a horizontal angle, thereby achieving three-dimensional imaging.

[0018] Differential interference is performed on each pixel of the 3D imaging at adjacent time intervals to obtain the deformation of each pixel in the 3D environment.

[0019] Optionally, a MIMO antenna array is used to perform digital beam scanning at each position on the horizontal linear guide rail, obtaining target echoes with multiple different elevation beams, including:

[0020] The MIMO antenna array performs a uniform linear scan along a horizontal linear guide rail. During the scan, for each position, the radar host transmits radar signals to the monitoring scene through the MIMO antenna array and receives echoes, thereby acquiring target echoes of different elevation beams at different times for each position on the horizontal linear guide rail.

[0021] Optionally, based on the target echo of each elevation beam scanned by the MIMO antenna array, synthetic aperture imaging is performed along a horizontal linear guide rail to obtain an image at a horizontal angle, thereby achieving three-dimensional imaging, including:

[0022] Fast Fourier transform is performed on the echo of each equivalent receiving channel of the MIMO antenna array at each position of the horizontal linear guide rail to obtain the range dimension information of the radar target.

[0023] Based on the echo of the MIMO antenna array, the angle information of the radar signal in the vertical pitch dimension is obtained by analysis, and the pitch dimension information of the monitoring scene is obtained.

[0024] By using synthetic aperture imaging algorithms, the azimuth direction synthetic aperture processing is performed by the same elevation beam at different positions on a horizontal linear guide rail using a MIMO antenna array, thereby obtaining the azimuth dimension information of the monitored scene.

[0025] By fusing the distance, elevation, and azimuth information, a three-dimensional image is reconstructed; the three-dimensional image includes the spatial coordinates and complex values ​​of each scattering point.

[0026] Optionally, using a digital beamforming algorithm or an equivalent MIMO processing algorithm, the angular information of the radar signal in the vertical pitch dimension can be obtained based on the three-dimensional imaging analysis at each location.

[0027] Optionally, for each pixel in the three-dimensional imaging at adjacent time intervals, differential interferometry is performed to obtain the deformation of each pixel in the three-dimensional environment, including:

[0028] The current 3D image and the next 3D image are registered, and conjugate multiplication is performed pixel by pixel to obtain the interferometric phase map;

[0029] The interferometric phase diagram is subjected to phase unwrapping and error correction processing, and converted into a displacement along the radar radial direction;

[0030] The displacement is assigned to the current 3D imaging and the next 3D imaging to obtain the deformation of each pixel in the 3D environment.

[0031] According to the specific embodiments provided in this application, this application has the following technical effects:

[0032] This application provides a three-dimensional imaging radar system and method for differential interferometric deformation monitoring. It employs a radar main unit, a horizontal linear guide rail, and a MIMO antenna array to form an instantaneous electronic scan, replacing the traditional pitch-oriented mechanical scan. This results in an orthogonal geometric configuration of linear SAR + vertical MIMO, decoupling data processing and enabling the application of computationally low-computation FFT-type algorithms. This significantly shortens the three-dimensional imaging time, increases monitoring frequency, and achieves a qualitative leap from slow diagnosis to rapid early warning. The orthogonal geometric configuration of linear SAR + vertical MIMO allows for the formation of a regular virtual rectangular planar aperture, facilitating the attribution of radial deformation to high-fidelity three-dimensional imaging. This ensures uniform resolution across the entire monitoring scene and high consistency of the point spread function, thereby providing extremely high phase fidelity for differential interferometry. Furthermore, the high efficiency of this application allows for a shorter revisit period, guaranteeing high coherence. Finally, the precise deformation measurement results are registered onto an equally precise three-dimensional imaging model, fundamentally improving the reliability of the monitoring results. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments 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.

[0034] Figure 1 A schematic diagram of the structure of a three-dimensional imaging radar system for differential interferometric deformation monitoring provided in an embodiment of this application;

[0035] Figure 2 This is a flowchart illustrating a three-dimensional imaging radar method for differential interferometric deformation monitoring, provided as an embodiment of this application. Detailed Implementation

[0036] 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 some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] This application provides an innovative solution that outperforms all existing solutions through a unique synergistic combination of "linear SAR + vertical MIMO" technologies.

[0038] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] This application provides a three-dimensional imaging radar system for differential interferometric deformation monitoring, such as... Figure 1 As shown, the system includes: a radar main unit, a horizontal linear guide rail, a MIMO antenna array, and a data processing and control unit.

[0040] The MIMO antenna array moves in a controlled manner on a horizontal linear guide rail. This horizontal linear guide rail can be a linear track with a high degree of straightness, used to support and guide the radar main unit in precise horizontal reciprocating translational movements.

[0041] The MIMO antenna array is electrically connected to the radio frequency front-end of the radar host, and the MIMO antenna array is perpendicular to the horizontal linear guide rail so that the MIMO antenna array can form a virtual linear array in the vertical direction through electronic scanning. The data processing and control unit is connected to the radar host through data lines and control lines to form a closed-loop control and data acquisition system.

[0042] The data processing and control unit controls the MIMO antenna array to perform uniform linear scanning along a horizontal linear guide rail. During the controlled movement of the MIMO antenna array on the horizontal linear guide rail, it performs digital beam scanning perpendicular to the guide rail direction at various positions along the rail. For each beam obtained by the MIMO antenna array scanning, the data processing and control unit performs synthetic aperture imaging along the horizontal linear guide rail to obtain a three-dimensional image of the target. It then performs continuous differential interferometry on each pixel in the three-dimensional image at adjacent times to obtain the deformation of each pixel. Specifically, the MIMO antenna array scans to obtain the amplitude and phase of N beams. These amplitudes and phases are then subjected to synthetic aperture imaging along the horizontal linear guide rail. After imaging, complex amplitudes and phases of M*N radar imaging units are obtained in each range dimension. These complex amplitudes and phases are then subjected to differential interferometry to obtain the deformation.

[0043] The data processing and control unit is typically a high-performance computer or embedded processing platform, responsible for controlling the radar host's transmission and reception, the movement of the MIMO antenna array, and processing, imaging, and analyzing the acquired data (i.e., sampled data).

[0044] As an optional implementation of this application, such as Figure 1 As shown, in practical applications, a MIMO antenna array (also known as a MIMO linear array) is equipped with multiple MIMO array equivalent elements (corresponding to...) Figure 1 (Referring to numbers 1 to N in the diagram). The MIMO antenna array is translated along a horizontal linear guide rail, sweeping across a regular virtual rectangular planar aperture in space.

[0045] As an optional embodiment of this application, the MIMO antenna array is fixedly mounted on the front end of the radar host and arranged vertically. It includes multiple transmitting antenna elements and multiple receiving antenna elements corresponding to the transmitting antenna elements. The multiple transmitting antenna elements and multiple receiving antenna elements are used to realize electronic beam scanning perpendicular to the horizontal linear guide rail, that is, to realize elevation angle imaging along the direction of the MIMO array.

[0046] As an optional implementation of this application, the radar host can be configured to include core radio frequency and digital circuit modules for transmitting, receiving, and processing radar signals.

[0047] Based on the same inventive concept, this application also provides a three-dimensional imaging radar method for differential interferometric deformation monitoring, which implements the aforementioned three-dimensional imaging radar system for differential interferometric deformation monitoring. The solution provided by this method is similar to the implementation scheme described in the above system. Therefore, the specific limitations in one or more embodiments of the three-dimensional imaging radar method for differential interferometric deformation monitoring provided below can be found in the limitations of the three-dimensional imaging radar method for differential interferometric deformation monitoring described above, and will not be repeated here.

[0048] In one exemplary embodiment, such as Figure 2 As shown, a three-dimensional imaging radar method for differential interferometric deformation monitoring, implemented using a pipelined collaborative processing mechanism, is provided, including:

[0049] Step 100: Using MIMO antenna array digital, perform digital beam scanning at each position on the horizontal linear guide rail to obtain target echoes with multiple different elevation beams.

[0050] Step 101: Based on the target echo of each elevation beam scanned by the MIMO antenna array, perform synthetic aperture imaging along a horizontal linear guide rail to obtain an image at a horizontal angle, thereby achieving three-dimensional imaging.

[0051] Step 102: Perform differential interference on each pixel of the three-dimensional imaging at adjacent time intervals to obtain the deformation of each pixel in the three-dimensional environment.

[0052] Based on the description of steps 100-102 above, the three-dimensional imaging radar method provided in this application mainly includes two stages: three-dimensional imaging and differential interferometric deformation monitoring. Steps 100 and 101 belong to the single-shot three-dimensional imaging stage. Steps 101 and 102 can also belong to the differential interferometric deformation monitoring stage.

[0053] As an optional implementation of this application, the process of implementing the single-shot three-dimensional imaging stage can be described as follows:

[0054] Step 1 (Azimuth Scanning and Data Acquisition): The MIMO antenna array performs a uniform linear scan along a horizontal straight guide rail. At each position during the scan, the radar host transmits radar signals to the monitored scene through the MIMO antenna array and receives the echoes, acquiring the target echoes from the elevation beam.

[0055] Step 2: Perform a Fast Fourier Transform (FFT) on the echo from each equivalent receiving channel of the MIMO antenna array at each position on the horizontal linear guide rail to obtain the range dimension information of the radar target. Based on this, range dimension resolution is achieved by the Fourier Transform of the time-domain signal.

[0056] Step 3 (Pitch Information Resolution): For the data collected at each location (i.e., sampled data), digital beamforming (DBF) or an equivalent MIMO processing algorithm is used to resolve the angle information of the radar signal in the vertical pitch dimension, obtaining the scene's pitch resolution (i.e., pitch dimension information). Based on this, pitch angle dimension resolution is achieved by MIMO antenna array beam scanning.

[0057] Step 4 (Azimuth Information Resolution): The target echoes from all elevation beams are processed using efficient frequency-domain synthetic aperture (SAR) imaging algorithms (such as the Range-Doppler algorithm RD or the Chirp Scaling algorithm CS) to perform azimuth pulse compression, obtaining high-resolution azimuth information (i.e., azimuth dimension information) of the scene. Based on this, the horizontal angular dimension is achieved by using the same elevation beam at different positions on a horizontal linear guide rail via a MIMO antenna array to perform synthetic aperture imaging along the horizontal linear guide rail.

[0058] Step 5 (3D Image Reconstruction): By fusing the range information obtained in Step 2, the elevation information obtained in Step 3, and the azimuth information obtained in Step 4, a 3D complex radar image (i.e., 3D imaging) of the monitored scene is reconstructed. This 3D complex radar image contains the spatial coordinates (X, Y, Z) of each scattering point and its complex values ​​(amplitude and phase). After processing in the above steps, based on the obtained range, elevation, and azimuth information, the target's position in 3D space can be restored using the radar position as the origin, thus obtaining the 3D complex radar image.

[0059] As an optional implementation of this application, the implementation process of the differential interferometric deformation monitoring stage can be described as follows:

[0060] Step 6 (Multi-temporal Data Acquisition): At the current moment, execute steps 1 to 5 to acquire the first three-dimensional complex radar image I0 (i.e., the three-dimensional imaging at the current moment). After a time interval, at the next moment, strictly repeat the process of steps 1 to 5 to ensure that the radar scanning trajectory is completely consistent with the system parameters, and acquire the second three-dimensional complex radar image I1 (i.e., the three-dimensional imaging at the next moment).

[0061] Step 7 (Interference Processing): The data processing and control unit registers images I0 and I1 and performs conjugate multiplication pixel by pixel to calculate the interference phase map Δφ.

[0062] Step 8 (Deformation Calculation and Display): The interferometric phase diagram Δφ is processed by phase unwrapping and error correction, and converted into a displacement along the radar line of sight (radial). Finally, this one-dimensional deformation field is accurately applied to the three-dimensional complex radar image generated in Step 4 to achieve a three-dimensional visualization of the deformation field.

[0063] Based on the above description, compared with the prior art, this application has the following advantages:

[0064] (1) Extremely high imaging and monitoring efficiency. In step 3 above, instantaneous electronic scanning is used to replace the traditional pitch-oriented mechanical scanning. In step 4, an efficient frequency domain SAR imaging algorithm is used to replace the inefficient time domain algorithm that must be used under other geometric configurations. This allows the orthogonal geometric configuration of linear SAR + vertical MIMO provided in this application to perform data processing and decoupling, thereby enabling the application of algorithms with extremely low computational complexity (e.g., Fast Fourier Transform (FFT)) to shorten the time of a single three-dimensional imaging from tens of minutes to a few minutes, thereby significantly increasing the monitoring frequency and achieving a qualitative change from slow diagnosis to rapid early warning.

[0065] (2) Excellent measurement accuracy and reliability. Steps 1 and 3 together form a regular virtual rectangular planar aperture. The strict repeated scanning emphasized in step 6, and the application of radial deformation to the high-fidelity 3D imaging model in step 8, all ensure uniform resolution across the entire scene and consistency of the point spread function (PSF), providing extremely high phase fidelity for differential interferometry. High efficiency allows for shorter revisit periods, ensuring high coherence. Finally, registering the accurate deformation measurement results to an equally accurate 3D imaging model fundamentally improves the reliability of the monitoring results.

[0066] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0067] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A three-dimensional imaging radar system for differential interferometric deformation monitoring, characterized in that, include: Radar main unit, horizontal linear guide rail, MIMO antenna array, and data processing and control unit; The MIMO antenna array is moved in a controlled manner on the horizontal linear guide rail; the MIMO antenna array is electrically connected to the radio frequency front end of the radar host, and the MIMO antenna array is perpendicular to the horizontal linear guide rail; the data processing and control unit is connected to the radar host via data lines and control lines; The MIMO antenna array performs a uniform linear scan along the horizontal linear guide rail. During the controlled movement of the MIMO antenna array on the horizontal linear guide rail, it performs digital beam scanning perpendicular to the guide rail direction at various positions on the guide rail. The data processing and control unit performs synthetic aperture imaging along the horizontal linear guide rail for each beam obtained by the MIMO antenna array to obtain a three-dimensional image of the target under test, and performs continuous differential interference on each pixel in the three-dimensional image of adjacent time to obtain the deformation of each pixel. A regular virtual rectangular planar aperture is formed by the orthogonal geometric configuration of linear SAR + vertical MIMO to facilitate the application of radial deformation to high-fidelity 3D imaging.

2. The three-dimensional imaging radar system for differential interferometric deformation monitoring according to claim 1, characterized in that, The MIMO antenna array is mechanically coupled to the horizontal linear guide rail via a sliding device.

3. The three-dimensional imaging radar system for differential interferometric deformation monitoring according to claim 1, characterized in that, The MIMO antenna array includes: multiple transmitting antenna units and multiple receiving antenna units corresponding to the transmitting antenna units; the multiple transmitting antenna units and the multiple receiving antenna units are used to realize electronic beam scanning perpendicular to the horizontal linear guide rail.

4. The three-dimensional imaging radar system for differential interferometric deformation monitoring according to claim 1, characterized in that, The radar host is configured to include radio frequency and digital circuit modules for transmitting, receiving, and processing radar signals.

5. A three-dimensional imaging radar method for differential interferometric deformation monitoring, characterized in that, The method is applied to a three-dimensional imaging radar system for differential interferometric deformation monitoring as described in any one of claims 1-4; the method includes: Using a MIMO antenna array, digital beam scanning is performed at each position on a horizontal linear guide rail to obtain target echoes with multiple different elevation beams. Based on the target echo of each elevation beam scanned by the MIMO antenna array, synthetic aperture imaging is performed along a horizontal linear guide rail to obtain an image at a horizontal angle, thereby achieving three-dimensional imaging. Differential interference is performed on each pixel of the 3D imaging at adjacent time intervals to obtain the deformation of each pixel in the 3D environment.

6. The three-dimensional imaging radar method for differential interferometric deformation monitoring according to claim 5, characterized in that, Using a MIMO antenna array, digital beam scanning is performed at each position on a horizontal linear guide rail to obtain target echoes with multiple different elevation beams, including: The MIMO antenna array performs a uniform linear scan along a horizontal linear guide rail. During the scan, for each position, the radar host transmits radar signals to the monitoring scene through the MIMO antenna array and receives echoes, thereby acquiring target echoes of different elevation beams at different times for each position on the horizontal linear guide rail.

7. The three-dimensional imaging radar method for differential interferometric deformation monitoring according to claim 5, characterized in that, Based on the target echo of each elevation beam scanned by the MIMO antenna array, synthetic aperture imaging is performed along a horizontal linear guide rail to obtain an image at a horizontal angle, thereby achieving three-dimensional imaging, including: Fast Fourier transform is performed on the echo of each equivalent receiving channel of the MIMO antenna array at each position of the horizontal linear guide rail to obtain the range dimension information of the radar target. Based on the echo of the MIMO antenna array, the angle information of the radar signal in the vertical pitch dimension is obtained by analysis, and the pitch dimension information of the monitoring scene is obtained. By using synthetic aperture imaging algorithms, the azimuth direction synthetic aperture processing is performed by the same elevation beam at different positions on a horizontal linear guide rail using a MIMO antenna array, thereby obtaining the azimuth dimension information of the monitored scene. By fusing the distance, elevation, and azimuth information, a three-dimensional image is reconstructed; the three-dimensional image includes the spatial coordinates and complex values ​​of each scattering point.

8. The three-dimensional imaging radar method for differential interferometric deformation monitoring according to claim 5, characterized in that, Using digital beamforming algorithms or equivalent MIMO processing algorithms, the angular information of the radar signal in the vertical pitch dimension is obtained based on the three-dimensional imaging analysis at each location.

9. The three-dimensional imaging radar method for differential interferometric deformation monitoring according to claim 5, characterized in that, For each pixel in a 3D image taken at adjacent time intervals, differential interferometry is performed to obtain the deformation of each pixel in the 3D environment, including: The current 3D image and the next 3D image are registered, and conjugate multiplication is performed pixel by pixel to obtain the interferometric phase map; The interferometric phase diagram is subjected to phase unwrapping and error correction processing, and converted into a displacement along the radar radial direction; The displacement is assigned to the current 3D imaging and the next 3D imaging to obtain the deformation of each pixel in the 3D environment.

Images