Measurement method and system based on interferometric synthetic aperture radar

Abstract

The invention relates to an interferometric synthetic aperture radar (InSAR)-based measurement method and system, and the method comprises the steps: determining the prior positions of a plurality of targets, and providing the prior positions to a ground processing unit; shooting an area where a plurality of targets are located by using an SAR satellite, and sending the obtained data to a ground processing unit; determining a phase difference between the targets for a single shot of the target; according to the determined phase difference and the SAR load wavelength, the slope distance between the targets is calculated through a ground processing unit; according to the slope distance and the satellite orbit information, the position relation between the targets is determined through a ground processing unit. The measuring system at least comprises a ground processing unit and an acquisition unit. According to the invention, shooting at the same track inclination angle and different track inclination angles can be realized, the limitation of heavy track shooting conditions in the prior art is broken through, and high-frequency and high-precision surface micro deformation measurement can be realized for different application scenes.

Description

Technical Field

[0001] This invention relates to the field of radar interferometric measurement technology, and in particular to a measurement method and system based on interferometric synthetic aperture radar (InSAR). Background Technology

[0002] Deformation monitoring technology based on spaceborne InSAR systems is an active microwave remote sensing technology. It has the ability to provide wide coverage, all-day and all-weather observation, and high-precision acquisition of surface deformation information. It has been widely used in fields such as mining subsidence monitoring, urban surface monitoring, slope deformation monitoring, deformation monitoring of key buildings, and disaster risk identification, providing technical support for the above applications.

[0003] Traditional spaceborne InSAR deformation monitoring systems require repeat orbit satellite remote sensing data. The high accuracy requirements of repeat orbit satellites, their high cost, and stringent technical requirements raise the barrier to entry for using InSAR technology to monitor minute surface deformations. Furthermore, the long revisit cycle of repeat orbit satellites cannot meet the needs of rapid deformation monitoring of ground features in different scenarios. In contrast, methods and devices for measuring minute surface deformations based on non-repeat orbit spaceborne SAR imagery have lower requirements for various image data indicators and can achieve high-frequency deformation monitoring of ground features through satellite collaborative planning. Simultaneously, by combining the placement scheme and spatial geometry of corner reflectors in specific scenarios, this type of method can achieve high-frequency, high-precision measurement of minute surface deformations.

[0004] CN112986949A discloses a method and apparatus for high-precision temporal deformation monitoring of SAR for corner reflectors. The method includes the following steps: extracting precise position information of each corner reflector from SAR images at various times; determining the total position offset information of each corner reflector in SAR image pairs at different times based on the precise position information of each corner reflector; determining the first position offset component information corresponding to the spatial baseline based on terrain and satellite orbit data; determining the second position offset component information corresponding to system error and environment based on natural isomorphic scattering target signals in SAR image pairs; determining the deformation position offset information corresponding to the corner reflector based on the total position offset information, the first position offset component information, and the second position offset component information of the SAR image pairs; and determining the high-precision deformation sequence of the corner reflector based on the deformation position offset information of the corner reflector.

[0005] However, this existing technical solution only uses amplitude information to calculate spatial position differences to obtain the precise location of ground points, without employing the principle of phase interferometry. Furthermore, the resolution of this non-interferometric SAR system is low, with results achieving an accuracy at most on the centimeter level. For example, the positions of each corner reflector are calculated using SAR images, and the corner reflector positions determined by SAR images inherently contain errors that cannot be eliminated. Since this measurement method requires calculating the total offset of the corner reflectors from multiple consecutive images, phase interferometry cannot be achieved, thus limiting accuracy. Moreover, this existing technical solution uses the same monitoring methods for different application scenarios, lacking scenario-specific adaptation, resulting in low accuracy of the monitoring results. Especially for application scenarios requiring the deployment of corner reflectors, different deployment strategies significantly affect the monitoring results.

[0006] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the applicant studied a large number of documents and patents when making this invention, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that the present invention does not possess the features of these prior art. On the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0007] To accurately determine the horizontal and vertical deformation of monitored targets, regional deformation monitoring techniques based on corner reflector InSAR technology have been proposed. For example, patent document CN114966678A discloses a ground-based InSAR deformation decomposition method based on vertical angles. This prior art solution includes: extracting radar line-of-sight deformation in the monitoring area based on corner reflector ground-based InSAR technology; deploying corner reflectors in the area to be monitored; and extracting the deformation of the monitoring area based on corner reflector InSAR technology. This process includes ground-based SAR image registration, interferometry, unwrapping, and deformation extraction; extracting the angle between the radar line-of-sight and the horizontal direction, where the radar line-of-sight is the line connecting the geometric centers of the radar and the corner reflector; and projecting the ground-based SAR line-of-sight deformation onto the horizontal and vertical directions using the angle decomposition equation to obtain the horizontal and vertical deformations. However, the deformation monitoring objects mainly involved in this prior art solution are radars and corner reflectors, especially corner reflectors in the ground monitoring area and radar equipment on satellites in the space environment. Here, the term "deformation" refers to the change in the radar line-of-sight. Such measurements neither reflect the phase difference between targets within the monitoring area nor avoid the deviation between corner reflectors and radar images caused by climatic conditions (especially atmospheric propagation delay). To at least partially solve the above-mentioned problems of the prior art, this invention provides a measurement method and system based on Interferometric Synthetic Aperture Radar (InSAR). Furthermore, this invention also provides an application of the Interferometric Synthetic Aperture Radar (InSAR) measurement method, particularly for settlement monitoring in areas with single buildings, linear engineering projects, key infrastructure areas, and / or defined areas.

[0008] In a first aspect, the present invention discloses a measurement method based on interferometric synthetic aperture radar (InSAR), the measurement method comprising the following steps: Determine the prior locations of several targets and provide them to the ground processing unit; The SAR satellite is used to photograph the area where several targets are located, and the acquired data is sent to the ground processing unit. Determine the phase difference between targets using a single shot; Based on the phase difference determined in the above steps and the payload wavelength of the SAR satellite, the slant range between targets is calculated using the ground processing unit; Based on the slant range and satellite orbit information, the positional relationship between targets is determined using a ground processing unit. Specifically, in a single measurement, the one-dimensional positional relationship between targets is determined to obtain the relative distance information between targets; in multiple measurements, the three-dimensional positional relationship between targets is determined.

[0009] Preferably, the SAR satellite of the present invention generally refers to a low Earth orbit (LEO) SAR satellite. Furthermore, the single image capture is performed by the LEO SAR satellite; that is, the SAR satellite images the target once when it passes within the target's line of sight.

[0010] According to a preferred embodiment, "determining the phase difference between targets in a single shot" includes: The ground processing unit processes the SAR echo data captured in the target area to form a single-view composite image product (SLC), which includes amplitude and phase information of the captured area. In single-view composite image products, the Sinc interpolation method is used to calculate the phase information of the coordinate point where the maximum amplitude of each target is located. Based on the phase information of each target, the phase difference between targets is calculated using the ground processing unit.

[0011] With the above configuration, the ground processing unit of the present invention can extract the "phase information of the coordinate point where the maximum amplitude is located" without knowing the absolute position of the coordinate point where the maximum amplitude is located.

[0012] According to a preferred embodiment, the "coordinate point where the maximum amplitude of each target is located" is the coordinate point where the maximum amplitude is located near the prior position of the corresponding target after Sinc interpolation, so as to determine the phase information of each target from the single-view polymorphic image product after Sinc interpolation.

[0013] According to a preferred embodiment, "determining the positional relationship between targets using a ground processing unit based on the slant range and satellite orbit information" includes: By using SAR satellites to take pictures "at least once within a specified time period", one-dimensional deformation information is obtained by analyzing the one-dimensional positional relationship difference between at least two sets of photographed targets. By using SAR satellites to take images “at least twice within a specified time period”, two-dimensional deformation information is obtained by analyzing the difference in two-dimensional positional relationship between at least two sets of photographed targets. By analyzing the differences in the three-dimensional positional relationships between at least two sets of images taken by SAR satellites "within a specified time period" to obtain three-dimensional deformation information, The specified time period refers to the time range within the monitoring area where deformation is negligible.

[0014] Some traditional measurement methods (such as CN112986949A) only focus on the positional difference of a single point between two images, failing to eliminate shooting errors caused by weather conditions. This invention, however, uses information from at least two points captured in a single image to determine the "line segment between points." This allows the one-dimensional deformation information obtained by this invention to "cancele common errors by calculating the difference between two simultaneously captured points," thus obtaining a deformation index for a monitoring area free from weather interference. Based on this, on-site verification is only arranged when the one-dimensional deformation information after offsetting weather interference exceeds a certain threshold. This significantly reduces false subsidence alarms caused by weather interference, reduces labor costs, and also greatly reduces computational data, allowing a single satellite to serve a wider monitoring area.

[0015] When the angle η is the same in two images taken within a specified time period (i.e., at the same orbital inclination), the two-dimensional position can be obtained because the angle η is the same. High-precision measurement can be achieved using images taken by a single satellite in a non-double orbit, avoiding the costs required to maintain a satellite in a double orbit. Preferably, the term "double orbit" refers to two images where both η and θ are the same, which is a special case of the same orbital inclination.

[0016] When determining three-dimensional positional relationships, multi-satellite joint monitoring can be used to achieve high-frequency imaging and shorten the monitoring cycle. This invention can utilize SAR images acquired from SAR satellites with different orbital inclinations to complete the measurement. Here, different orbital inclinations refer to situations where the η of two images is different, such as images taken by two satellites simultaneously, or images taken by the same satellite during its ascent and descent.

[0017] According to a preferred embodiment, the area captured by a SAR satellite includes at least a number of targets arranged according to a specific rule, and the placement positions of at least some of the targets are related to each other, so that a specific geometric shape formed by the related targets has corresponding geometric feature points.

[0018] Through the above configuration, this invention can circumvent the integer ambiguity problem that is difficult to address in existing technologies. For example, methods for calculating the integer number using prior knowledge are too complex and difficult to use to determine the slant distance deformation value. However, the corner reflectors arranged according to specific rules in this invention can form at least one geometric overlap point (center point). Since the integer number of this geometric overlap point (center point) is zero, the slant distance deformation value between any two corner reflectors can be measured quickly.

[0019] Existing technologies typically employ different corner reflector deployment schemes as a means to address the range-time (fast time) and azimuth-time (slow time) errors inherent in spaceborne SAR systems. For example, patent document CN110865346A discloses a spaceborne SAR time parameter calibration method based on a direct positioning algorithm, comprising the following steps: calibration area selection and corner reflector deployment; corner reflector pointing adjustment and scattering center position measurement; imaging and image upsampling processing; determination of nominal azimuth time and slant range of the corner reflectors; fitting of the SAR antenna phase center position and velocity; comprehensive processing of fitting coefficients; establishment of calibration equations; solution of calibration equations; atmospheric delay compensation; solution of azimuth-time (slow time) and slant range errors; averaging of multi-corner reflector processing results; averaging of multiple observation processing results; and traversal calibration of the radar system's transmitted signal form, ultimately obtaining the azimuth-time (slow time) and slant range correction parameters for the spaceborne SAR. However, the existing technical solution only involves placing one corner reflector at the center of each calibration area. Its purpose is to ensure that the strongest scattering direction of the corner reflector coincides with the direction of the radar beam center, thereby accurately measuring the scattering center position of the corner reflector and obtaining its coordinates in the geocentric fixed coordinate system. However, when the target of this invention is a corner reflector, it has a specific arrangement. The placement of corner reflectors with coincident geometric centers is determined based on the type and morphological characteristics of the object to be monitored, resulting in several corner reflectors forming a specific geometric shape. This invention determines the relative distance between two corner reflectors with known locations through a single measurement. Furthermore, since this invention determines the phase difference between two targets through a single image of the target, the targets are located within the same monitoring area, thus obtaining a deformation index for a monitoring area after eliminating climate interference. Compared with the aforementioned existing technology, this invention can select SAR images from different time periods, calculate the phase deformation values ​​of geometric feature points in the target area, and obtain a surface deformation result map within the interval. Based on the above-mentioned distinguishing technical features, the problems to be solved by this invention include: how to improve the efficiency of acquiring deformation information of the target area in the study area. Specifically, the technical solution provided by this invention can rapidly acquire deformation information of target areas in the study area through high-frequency monitoring under non-re-track conditions. This facilitates the rapid identification of potential deformation areas of ground features in different scenarios, thereby providing high-frequency target images and phase deformation data on a regular basis, which plays a positive role in infrastructure deformation monitoring and early warning. Simultaneously, the technical solution provided by this invention can achieve rapid, large-scale detection of surface deformation, quickly extract the deformation range, and greatly improve the efficiency of calculating and identifying local deformation values.

[0020] In a second aspect, the present invention discloses a measurement system based on interferometric synthetic aperture radar (InSAR), which includes at least a ground processing unit for processing data and an acquisition unit configured on a SAR satellite, wherein... The ground processing unit is able to receive the determined prior locations of several targets; The acquisition unit on the SAR satellite takes pictures of the area where several targets are located and sends the acquired data to the ground processing unit. The ground processing unit can determine the phase difference between targets based on a single image captured of the target; The ground processing unit calculates the slant range between targets based on the determined phase difference and the payload wavelength of the SAR satellite; The ground processing unit determines the positional relationship between targets based on the slant range and satellite orbit information. Specifically, in a single measurement, the one-dimensional positional relationship between targets is determined, i.e., the relative distance information between targets; in multiple measurements, the three-dimensional positional relationship between targets is determined.

[0021] According to a preferred embodiment, the ground processing unit can process SAR echo data captured for the area where the target is located when determining the phase difference between targets, so as to form a single-view complex image product (SLC) which includes amplitude and phase information of the captured area. The ground processing unit uses the Sinc interpolation method to calculate the phase information of the coordinate point where the maximum amplitude of each target is located in the single-view composite image product; The ground processing unit calculates the phase difference between targets based on the phase information of each target.

[0022] According to a preferred embodiment, the "coordinate point where the maximum amplitude of each target is located" determined by the ground processing unit is the coordinate point where the maximum amplitude is located near the prior position of the corresponding target after Sinc interpolation, so as to determine the phase information of each target from the single-view polymorphic image product after Sinc interpolation.

[0023] According to a preferred embodiment, when the acquisition unit on a SAR satellite takes pictures "at least once within a specified time period", the ground processing unit obtains one-dimensional deformation information by analyzing the one-dimensional positional relationship difference between at least two sets of captured targets. With the help of the acquisition unit on the SAR satellite taking pictures "at least twice within a specified time period", the ground processing unit obtains two-dimensional deformation information by analyzing the difference in two-dimensional positional relationship between at least two sets of photographed targets. With the aid of the acquisition unit on a SAR satellite taking at least three images within a specified time period, the ground processing unit obtains three-dimensional deformation information by analyzing the differences in the three-dimensional positional relationship between at least two sets of images of the target. The specified time period refers to the time range within the monitoring area where deformation is negligible.

[0024] According to a preferred embodiment, the measurement system includes a plurality of reflective units arranged in a specific rule as targets for the acquisition unit to capture images, wherein at least some of the reflective units are arranged in a mutually related manner, such that a specific geometric shape formed by the mutually related reflective units has corresponding geometric feature points.

[0025] In a third aspect, the present invention discloses the application of the above-mentioned measurement method based on interferometric synthetic aperture radar (InSAR) in settlement / subsidence monitoring, wherein several targets can be deployed in a specific arrangement rule in the area of ​​the single building to be monitored, the linear engineering area, the key infrastructure area and / or the limited range area to perform the InSAR-based measurement method.

[0026] Compared with the prior art, the present invention deploys corner reflectors in a specific manner for different targets, that is, determines the corresponding deployment scheme based on the specific deployment rules of the monitored object. Based on the above distinguishing technical features, the problems to be solved by the present invention include: how to improve the deformation measurement accuracy of different monitoring areas. Specifically, the corner reflectors of the present invention can be distributed in a specific pattern to satisfy the coincidence of feature points, and differential calculation is performed using linear relationship constraints. As the number of corner reflectors and the target monitoring range increase, the specific geometric shape that can form a geometric center coincidence becomes more linear, and the constraint becomes stronger. As the number of observations increases, the systematic error becomes smaller. Through this setting method, the present invention can avoid the integer ambiguity problem that is difficult to deal with in the prior art. For example, the method of calculating the number of integer cycles using prior knowledge is too complicated and inconvenient to use to determine the slant distance deformation value. The present invention can form at least one geometric overlap point with corner reflectors arranged in a specific pattern. Since the number of integer cycles at the geometric overlap point is zero, the slant distance deformation value between each pair of corner reflectors can be measured quickly.

[0027] According to a preferred embodiment, several targets are arranged in a single building area according to the following layout rule: There exists at least one set of targets, where the geometric center of the geometry formed by all targets in this set coincides with the geometric center of the geometry formed by all targets in another set of targets, and there are no common targets in the two sets. The points where the geometric centers coincide are: The point where the line segment connecting the first and third objectives belonging to one set of objectives intersects with the line segment connecting the second and fourth objectives belonging to another set of objectives.

[0028] According to a preferred embodiment, several targets are arranged in a linear engineering region according to the following arrangement rule: There exists at least one set of targets, where the geometric center of the geometry formed by all targets in this set coincides with the geometric center of the geometry formed by all targets in another set of targets, and there are no common targets in the two sets. The points where the geometric centers coincide are: The point where the line segment connecting the first and third targets belonging to one set of targets intersects with the location of the second target belonging to another set of targets.

[0029] According to a preferred embodiment, several targets are arranged in key infrastructure areas according to the following layout rules: There exists at least one set of targets, where the geometric center of the geometry formed by all targets in this set coincides with the geometric center of the geometry formed by all targets in another set of targets, and there are no common targets in the two sets. The points where the geometric centers coincide are: The intersection of the line segment connecting the first and fourth objectives belonging to one set of objectives, the line segment connecting the second and fifth objectives belonging to another set of objectives, and the line segment connecting the third and sixth objectives belonging to yet another set of objectives.

[0030] According to a preferred embodiment, a plurality of targets are arranged in a defined area according to the following arrangement rule: There exists at least one set of targets where the geometric center of the geometry formed by all targets in this set coincides with the geometric center of the geometry formed by all targets in another set of targets, and there are no common targets in the two sets. The location where the geometric centers coincide depends on the method used to divide the target sets. The intersection of the line segment connecting the first and fourth objectives, the line segment connecting the second and fifth objectives, the line segment connecting the third and sixth objectives, and the point where the seventh objective is located.

[0031] The beneficial technical effects of this invention compared to existing technologies are at least as follows: This invention provides a measurement method and system based on Interferometric Synthetic Aperture Radar (InSAR). It acquires InSAR images of the monitored object or its surrounding area, sorts them according to the shooting time, and calculates the phase deformation values ​​of geometric feature points in the target area using SAR images from different time periods, obtaining a surface deformation result map within the interval. The technical solution provided by this invention enables rapid acquisition of deformation information of the target area in the study area through high-frequency monitoring under non-re-orbit conditions. This is beneficial for the rapid identification of potential deformation areas of ground features in different scenarios, and can periodically provide high-frequency target images and phase deformation data, playing a positive role in infrastructure deformation monitoring and early warning. The technical solution provided by this invention enables rapid, large-scale detection of surface deformation, rapid extraction of the deformation range, and greatly improves the efficiency of calculating and identifying local deformation values. Compared with CN112986949A, this invention adopts the phase interferometry principle, determining the relative distance between two corner reflectors with known positions through a single measurement. The phase interferometry principle determines that the accuracy of this invention can reach the millimeter level, significantly better than the centimeter level of CN112986949A. Attached Figure Description

[0032] Figure 1 A flowchart of an InSAR-based measurement method according to a preferred embodiment of the present invention; Figure 2 This is a schematic diagram of a corner reflector in a SAR image according to a preferred embodiment of the present invention; Figure 3 This is a schematic diagram of a preferred embodiment of the present invention. Figure 4 This is a simulation result diagram of a preferred embodiment of the present invention; Figure 5 This is a simplified structural diagram of an InSAR-based measurement system according to a preferred embodiment of the present invention; Figure 6 This is a preferred embodiment of the present invention, showing an example of corner reflector layout for different application scenarios; Figure 7 This is a field layout diagram of the corner reflector according to an embodiment of the present invention; Figure 8 For corresponding Figure 7 SAR imagery of an example.

[0033] List of reference numerals 100: Ground processing unit; 200: Acquisition unit; 300: Reflection unit. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings.

[0035] Existing InSAR deformation monitoring systems commonly use the single-point multi-temporal interferometry method, which involves performing SAR measurements on the same target at different times. This requires satellites to acquire remote sensing data at different times under double orbit conditions, which places high demands on the accuracy of satellite double orbit and increases the cost of satellite operation. The relatively higher technical requirements not only limit the application of InSAR technology in measuring small surface deformations, but also make it difficult to achieve high-frequency deformation monitoring of ground objects through satellite collaborative planning due to the long satellite revisit cycle.

[0036] Some existing technical solutions (such as CN112986949A) attempt to solve the registration problem between two images captured by the corner reflector in the double-track interferometry system. However, the core of these solutions is to find the position of the corner reflector in the two images captured in sequence as the coincidence point to obtain the overall phase relationship between the two images. Therefore, theoretically, only one corner reflector is needed to assist in the registration.

[0037] Unlike traditional methods, this invention utilizes spatial interferometry instead of temporal interferometry, overcoming the limitations of double-tracking requirements by simultaneously imaging multiple targets. This fundamentally solves the problem of difficult registration between two images in double-tracking interferometry. Furthermore, this invention focuses on the phase relationship between corner reflectors in each image during monitoring, rather than the overall phase relationship between two images. Theoretically, at least two corner reflectors are required to establish a geometric relationship.

[0038] Therefore, the application of the InSAR-based measurement method proposed in this invention is a study conducted from a completely different perspective than existing technologies. Due to this fundamental difference, those skilled in the art would not have derived the research motivation and purpose of this invention based on existing technologies.

[0039] Furthermore, this invention innovatively arranges several targets (e.g., corner reflectors) in a specific rule within a corresponding area based on the type of the object to be monitored. This not only limits the number of corner reflectors used in this invention to at least two, but also clarifies that the corner reflectors need to be arranged according to a specific rule. In existing technologies, the process for handling integer ambiguity problems is overly complex. For example, the steps for calculating integer numbers using prior knowledge include: first measuring the absolute distance between two observation points, and then projecting the three-dimensional spatial data (e.g., observation angle) from satellite observations onto the slant range plane to calculate the distance difference (or slant range deformation value) between the two observation points on the slant range plane. This invention, however, can achieve a simple and accurate solution to integer ambiguity problems while overcoming the limitations of double orbit requirements. The technical solution and its resulting technical effects are not obvious and have outstanding substantive features and significant progress compared to existing technologies.

[0040] Example 1 like Figure 1 As shown, the InSAR-based measurement method of the present invention includes the following steps: S1. Deploy several targets in the corresponding area according to a specific arrangement rule, and provide the prior positions of the above targets to the ground processing unit. S2. Use SAR satellites to photograph the areas where several targets are located, and send the photographed data to the ground processing unit; S3. Perform a single shot at the target to determine the phase difference between targets; S4. Based on the phase difference and SAR payload wavelength determined in step S3, calculate the slant range between targets using the ground processing unit; S5. Based on the slant range and satellite orbit information, the positional relationship between the targets is determined using the ground processing unit. Specifically, in a single measurement, the one-dimensional positional relationship between the targets is determined to obtain the relative distance information between the targets; in multiple measurements, the three-dimensional positional relationship between the targets is determined.

[0041] Preferably, in step S1, there may be several targets around the monitored object, wherein the targets may be radar reflectors and / or ground feature points. These targets are pre-deployed on the ground or pre-selected, and their positions are determined using measurement principles such as optics and GPS. Preferably, the radar reflector can be made of metal sheet and can be made into different specifications according to actual use. The radar reflector may be, for example, a corner reflector, so that when the electromagnetic waves emitted by the SAR are scanned by the corner reflection, the electromagnetic waves will be refracted and enhanced at the metal corner, generating a strong echo signal sufficient to be captured by the SAR. Further, in this invention, the corner reflector as a target may be assembled together by two or three cross-mounted conductive planes perpendicular to each other. After the incident electromagnetic waves are reflected multiple times by the planes, an echo parallel to the incident direction is formed. Therefore, the corner reflector has strong backscattering characteristics and the radar cross-section changes little over a large angular range. Preferably, when deploying targets (such as corner reflectors) in the corresponding area, they should be as far away as possible from interference sources and as far away as possible from obstructions (such as buildings, trees, etc. that are taller than the target).

[0042] Preferably, some targets are deployed based on specific rules, such that these targets are geometrically related. Preferably, these targets may include existing ground feature points around the monitored object and / or newly installed radar reflectors (such as corner reflectors), as long as the specific rules are met. Therefore, this embodiment will be described with all targets being corner reflectors, but the invention is not limited to this; any deployed corner reflector may be replaced with existing ground feature points that meet the specific rules.

[0043] Preferably, one or more targets can be grouped into a target set, and any target can be grouped into one or more target sets. More preferably, the specific rule includes: at least one target set exists where the geometric center of all targets in this set coincides with or substantially coincides with the geometric center of all targets in another target set, and there are no common targets in the two target sets. The targets in these two target sets are interconnected and can form target set pairs.

[0044] Furthermore, the term "geometric center" refers to the central location of a symmetrical geometric shape composed of multiple objects, such as the midpoint of any line segment in space, the intersection of the two diagonals of a rectangle or parallelogram, or the center of a circle. When a shape with a geometric center undergoes symmetrical transformations that allow it to overlap itself, its axis of rotation, axis of symmetry, and pivot point must all pass through its geometric center. In other words, the aforementioned geometric center does not refer to the center of a single object itself, but rather to the geometric center of the geometric shape formed by constructing different line segments in space, using the centers of each object as endpoints.

[0045] Furthermore, the term "coincidence" refers to a distance on the order of millimeters between any two points in space. Due to various factors such as actual geographical conditions, it is usually difficult to achieve complete and precise coincidence of the intersection points of different line segments during the deployment of targets, thus allowing for errors. This invention limits this error to the order of millimeters to ensure measurement accuracy.

[0046] In other words, when the target is a corner reflector, its specific arrangement can be determined as follows: Based on the type and morphological characteristics of the monitored object, the geometric shape formed by the corner reflectors is determined so that its geometric center coincides with the geometric center of the monitored object, thereby enabling these correspondingly deployed corner reflectors to form a specific geometric shape. Furthermore, the type characteristics of the monitored object can refer to its category or level; the morphological characteristics can refer to its spatial distribution characteristics, such as a one-dimensional line, a two-dimensional surface region, or a three-dimensional solid structure. The placement of the corner reflectors can be adjusted based on the spatial distribution characteristics of the monitored object, the required measurement frequency, and the required measurement accuracy, adjusting parameters such as their number and spacing.

[0047] Preferably, the specific geometric shape formed by the arrangement of several corner reflectors can refer to a shape whose geometric center basically or completely coincides with the geometric center of the monitored object, such as a rectangle, parallelogram, or regular hexagon. It should be noted that the geometric shape of the monitored object mentioned here does not mean that the building and / or area being monitored must have a regular geometric shape to meet the condition of coincident geometric centers. If the monitored object itself does not have a regular geometric shape, the overall layout area of ​​the corner reflectors can conform to a specific geometric shape when setting them up.

[0048] Preferably, in step S2, the SAR satellite typically refers to a low-Earth orbit (LEO) SAR satellite. Further, the single image capture is performed by the LEO SAR satellite, that is, when the SAR satellite passes within the target's line of sight, the image is captured. For example, an image captured by the SAR satellite is shown below. Figure 2 As shown. Preferably, in another preferred embodiment of the present invention, the method of acquiring SAR images is not limited, and any legal means can be used to acquire them, as long as the authenticity and reliability of the obtained SAR image data are ensured. For example, they can be acquired through a newly launched SAR satellite system, purchased from an existing SAR remote sensing image database, or acquired through an aircraft carrying a SAR system.

[0049] Preferably, the ground processing unit is configured to determine the phase difference through calculation. Further, the ground processing unit is configured to interact with the SAR satellite to obtain imaging parameter information of the SAR satellite, such as SAR payload wavelength data, satellite orbit information, and satellite attitude information.

[0050] Preferably, step S3 includes: S3.1 The ground processing unit processes the SAR echo data captured for several targets to form a single-view complex image product (SLC), which includes amplitude and phase information of the captured area; S3.2 In the single-view composite image product (SLC), the Sinc interpolation method is used to calculate the phase information of the coordinate point where the maximum amplitude of each target is located. The "coordinate point where the maximum amplitude of each target is located" refers to the coordinate point near the prior position of the corresponding target after Sinc interpolation and reaching the maximum amplitude, so as to determine the phase information of each target from the single-view composite image product (SLC) after Sinc interpolation. S3.3 The ground processing unit calculates the phase difference between targets based on the phase information of each target.

[0051] Preferably, the single-view complex image product (SLC) is a slant range complex data product obtained after imaging processing and relative radiometric calibration based on satellite parameters, to provide slant-to-ground conversion coefficients, wherein the complex data product retains amplitude, phase, and polarization information.

[0052] This configuration allows the ground processing unit of the present invention to directly extract the "phase information" of the coordinate point where the maximum amplitude is located without needing to know the absolute position of the coordinate point where the maximum amplitude is located.

[0053] Preferably, the calculation method for step S3 is as follows: Perform two-dimensional fast Fourier transform (FFT) on the I and Q channels of the SAR image, convert the time domain to the frequency domain, perform zero-padding and interpolation, and stretch the image by n times. Perform a two-dimensional inverse fast Fourier transform (IFFT) to complete the frequency domain to time domain conversion calculation; Calculate and solve for the target phase information; Calculate the phase difference ΔP between the geometric center points of monitored objects A and B within the target area using SAR imagery: .

[0054] Specifically, in step S3, the ground processing unit can set the image as a function with two variables x and y, introducing a Fourier transform of a two-dimensional continuous function. Let... It is a function of two independent variables x and y, and satisfies ,but The Fourier transform is defined as: .

[0055] Stretch the Fourier transform image by a factor of n to obtain a new image. : .

[0056] Perform a two-dimensional inverse fast Fourier transform (IFFT) to complete the frequency domain to time domain calculation: .

[0057] Given the real and imaginary parts, calculate the phase of the angle reflector: , in The real part represents the SAR image band. The imaginary part representing the SAR image band; This represents the phase information of SAR images.

[0058] Specifically, in step S3, the phase value of the geometric feature point of the monitored object can be obtained by spatially differencing the phase value of each corner reflector feature point set in the corner reflector deployment area where its geometric center coincides with the geometric center of the monitored object.

[0059] Preferably, the corner reflectors are distributed according to a specific pattern to ensure the coincidence of feature points, and differential calculations are performed using linear constraints. As the number of corner reflectors and the target monitoring range increase, the specific geometric shape constituting the coincidence of geometric centers becomes more linear, and the constraint becomes stronger. Therefore, the systematic error decreases with the increase of the number of observations.

[0060] This arrangement allows the present invention to circumvent the integer ambiguity problem that is difficult to address in existing technologies. For example, methods for calculating the number of integer cycles using prior knowledge are too complex and difficult to use to determine the slant distance deformation value. However, the corner reflectors of the present invention, arranged according to specific rules, can form at least one geometric overlap point (i.e., the center point). Since the number of integer cycles at the geometric overlap point (i.e., the center point) is zero, the slant distance deformation value between any two corner reflectors can be measured quickly.

[0061] Preferably, the calculation method for step S4 is as follows: , Where ΔP represents the geometric center phase difference between monitoring objects A and B in a single observation, P A P represents the geometric center phase of the monitored object A in a single observation. B The geometric center phase of the monitored object B in a single observation, where λ represents the carrier wavelength; L A L represents the slant range of the satellite relative to the monitored object A during a single observation. B ΔL represents the slant distance of the satellite relative to the monitored object B during a single observation, and ΔL represents the slant distance deformation value between points A and B during a single observation.

[0062] Figure 3 This diagram illustrates the measurement principle of this invention based on InSAR. In the figure, A and B represent the positions of each monitored object during a single SAR satellite image. Solid lines represent the current trajectory of the satellite, dotted lines represent the trajectory of points below the satellite, and dashed lines represent latitude lines on Earth. The symbol η represents the angle between the satellite's direction of motion and the latitude line in the Earth's plane, a constant related to the satellite's orbit. The symbol θ represents the observation angle or incident angle, a constant related to each satellite image.

[0063] Preferably, based on the slant range deformation value and satellite orbit information obtained in step S4, the ground processing unit can use the approximately linear or nonlinear relationship between the distance component between two points and the carrier phase difference to determine the positional relationship between targets, thereby obtaining the phase transformation deformation information of the monitored object. That is, the calculation method of step S5 is as follows: , Where, ΔL x ΔL represents the latitudinal component of the line segment within its projection onto the Earth's surface; it is a variable related to the line segment. y ΔL represents the longitude component of a line segment projected onto the ground plane; it is a variable related to the line segment. h This represents the projected length of the line segment onto the Earth's central axis and is a variable related to the line segment; the aforementioned ground plane refers to the perpendicular plane connecting the center point of line segment AB to the Earth's center.

[0064] Specifically, step S5 may include: S5.1. When taking at least one photograph within a specified time period using a low-orbit SAR satellite, one-dimensional deformation information is obtained by analyzing the one-dimensional positional relationship difference between at least two sets of photographed targets. S5.2. When taking at least two images within a specified time period using a low-orbit SAR satellite, obtain two-dimensional deformation information by analyzing the difference in two-dimensional positional relationship between at least two sets of images of the target. S5.3. When taking at least three images within a specified time period using a low-orbit SAR satellite, obtain three-dimensional deformation information by analyzing the difference in three-dimensional positional relationship between at least two sets of images of the target.

[0065] More preferably, the specified time period refers to the time range within the monitoring area where deformation is negligible.

[0066] Preferably, the one-dimensional deformation information represents the positional changes between each pair of targets.

[0067] according to Figure 4 The simulation results shown demonstrate that the elevation measurement error of the monitored object obtained using the above method can be controlled within the millimeter level, avoiding phase deviation caused by SAR coherent processing. High-frequency monitoring based on a single satellite and without the need for multiple orbits can significantly reduce phase deviation caused by topographic and atmospheric changes. It can quickly acquire deformation information of the target area in the study area, facilitating the rapid identification of potential deformation areas in different scenarios. It can also regularly provide high-frequency target images and phase deformation information, playing a positive role in infrastructure deformation monitoring and early warning.

[0068] Example 2 This embodiment is a further improvement on embodiment 1, and repeated content will not be described again.

[0069] Figure 5 This is a simplified structural diagram of an InSAR-based measurement system according to a preferred embodiment of the present invention. As shown in the figure, the present invention discloses an InSAR-based measurement system, which includes at least a ground processing unit 100 for processing data and an acquisition unit 200 configured on a SAR satellite.

[0070] The ground processing unit 100 is configured to receive prior locations of several targets that have been determined.

[0071] The acquisition unit 200 on the SAR satellite takes pictures of the areas where several targets are located and sends the acquired data to the ground processing unit 100.

[0072] The ground processing unit 100 determines the phase difference between targets based on a single shot of the target.

[0073] The ground processing unit 100 calculates the slant range between targets based on the determined phase difference and the payload wavelength of the SAR satellite.

[0074] The ground processing unit 100 determines the positional relationship between targets based on the slant range and satellite orbit information. Specifically, in a single measurement, the one-dimensional positional relationship between targets is determined, i.e., the relative distance information between targets; in multiple measurements, the three-dimensional positional relationship between targets is determined.

[0075] Preferably, the measurement system can be used to implement the measurement method as described in Example 1.

[0076] Preferably, the ground processing unit 100 processes SAR echo data captured for the target area when determining the phase difference between targets to form a single-view composite image product (SLC) that includes amplitude and phase information of the captured area.

[0077] The ground processing unit 100 uses the Sinc interpolation method to calculate the phase information of the coordinate point where the maximum amplitude of each target is located in the single-view composite image product.

[0078] Subsequently, the ground processing unit 100 calculates the phase difference between targets based on the phase information of each target.

[0079] Preferably, the "coordinate point where the maximum amplitude of each target is located" determined by the ground processing unit 100 is the coordinate point where the maximum amplitude is located near the prior position of the corresponding target after Sinc interpolation, so as to determine the phase information of each target from the single-view polymorphic image product after Sinc interpolation.

[0080] Preferably, when the acquisition unit 200 on the SAR satellite takes pictures "at least once within a specified time period", the ground processing unit 100 obtains one-dimensional deformation information by analyzing the one-dimensional positional relationship difference between at least two sets of photographed targets.

[0081] Optionally, when the acquisition unit 200 on the SAR satellite takes pictures "at least twice within a specified time period", the ground processing unit 100 obtains two-dimensional deformation information by analyzing the difference in two-dimensional positional relationship between at least two sets of photographed targets.

[0082] Alternatively, if the acquisition unit 200 on the SAR satellite takes at least three images within a specified time period, the ground processing unit 100 obtains three-dimensional deformation information by analyzing the difference in three-dimensional positional relationship between at least two sets of images of the target.

[0083] The specified time period refers to the time range within the monitoring area where deformation is negligible.

[0084] Preferably, the measurement system includes a plurality of reflective units 300 arranged in a specific rule as targets for the acquisition unit 200 to capture images, wherein at least some of the reflective units 300 are arranged in a mutually related manner, such that a specific geometric shape formed by the mutually related reflective units 300 has corresponding geometric feature points.

[0085] Preferably, the reflecting unit 300 can be configured as a corner reflector. When the electromagnetic waves emitted by the SAR are scanned by the corner reflection, the electromagnetic waves will be refracted and amplified at the metal corner, generating a strong echo signal that is strong enough to be captured by the SAR.

[0086] Example 3 This embodiment is a further improvement on embodiment 1, and repeated content will not be described again.

[0087] In this embodiment, the InSAR-based measurement method can be used for settlement monitoring of a single building area. Preferably, when monitoring settlement / subsidence of a single building area, several targets can be arranged in the single building area according to the following rules: There exists at least one set of targets, wherein the geometric center of the geometry formed by all targets in this set coincides with the geometric center of the geometry formed by all targets in another set of targets, and there are no common targets in the two sets of targets.

[0088] Preferably, when conducting settlement monitoring for a single building area, one can select... Figure 6 (a) The corner reflectors are deployed in the manner described. When the area of ​​the single building to be monitored is rectangular or parallelogram-shaped, corner reflectors can be placed at the four corner points. The deployment method must meet the principle of geometric center coincidence to utilize the mutual interference and spatial difference principle between the two points, thereby solving the problem of phase integer ambiguity. The spacing between adjacent corner reflectors depends on the area of ​​the single building to be monitored, and can be selected from 10m to 500m. Alternatively, when the area of ​​the single building to be monitored is not completely rectangular or parallelogram-shaped, the corner reflectors can be deployed in the following manner: the deployment area formed by them has a specific geometric shape (especially rectangular or parallelogram-shaped) and the deployment area formed by them at least contains the target location or area to be monitored. Preferably, the pitch angle and azimuth angle of the corner reflectors are determined according to the actual situation.

[0089] Preferably, such as Figure 6 As shown in (a), four targets (i.e., the first target, the second target, the third target, and the fourth target) can be deployed in the single building area. Each target can have a corresponding phase value (i.e., P1, P2, P3, and P4). The line connecting the first target and the third target intersects the line connecting the second target and the fourth target only once. That is, the line segment (first target - third target) intersects the line segment (second target - fourth target).

[0090] Preferably, the location where the geometric centers coincide is the intersection of the line segment connecting the first and third targets belonging to one set of targets and the line segment connecting the second and fourth targets belonging to another set of targets.

[0091] Preferably, in step S3, the phase value of the geometric feature point of the monitored object can be obtained by spatially differencing the phase value of each corner reflector feature point set in the corner reflector deployment area whose geometric center coincides with the geometric center of the monitored object. For the settlement / settlement monitoring process of a single building area, the phase value of the corner reflector geometric feature point can be calculated according to the following formula: .

[0092] Example 4 This embodiment is a further improvement on embodiment 1, and repeated content will not be described again.

[0093] In this embodiment, the InSAR-based measurement method can be used for settlement monitoring in linear engineering areas, where the linear engineering area includes transportation routes such as high-speed railways, highways, and / or subways. Preferably, when monitoring settlement / subsidence in a linear engineering area, several targets can be arranged in the linear engineering area according to the following rules: There exists at least one set of targets, wherein the geometric center of the geometry formed by all targets in this set coincides with the geometric center of the geometry formed by all targets in another set of targets, and there are no common targets in the two sets of targets.

[0094] Preferably, when conducting settlement monitoring for linear engineering areas, one can select... Figure 6 (b) The corner reflectors are deployed in accordance with the method described. The number of corner reflectors is selected based on the linear area, with the general principle being one corner reflector at each end and one in the middle of the linear area. The problem of phase integer ambiguity can be solved by utilizing the mutual interference and spatial difference principle between two points. The number and spacing of the corner reflectors increase with the required accuracy. The spacing between adjacent corner reflectors depends on the linear engineering area to be monitored, and can be selected from 10m to 500m. Preferably, the elevation and azimuth angles of the corner reflectors are determined based on the actual situation.

[0095] Preferably, such as Figure 6 As shown in (b), three targets (i.e., the first target, the second target, and the third target) can be deployed in the linear engineering region. Each target can have a corresponding phase value (i.e., P1, P2, P3). The lines connecting the first target, the second target, and the third target are collinear with each other.

[0096] Preferably, the location where the geometric centers coincide can be the intersection of the line segment connecting the first and third targets belonging to one set of targets and the location of the second target belonging to another set of targets.

[0097] Preferably, in step S3, the phase value of the geometric feature point of the monitored object can be obtained by spatially differencing the phase value of each corner reflector feature point set in the corner reflector deployment area whose geometric center coincides with the geometric center of the monitored object. For the settlement / subsidence monitoring process in a linear engineering area, the phase value of the corner reflector geometric feature point can be calculated according to the following formula: .

[0098] Example 5 This embodiment is a further improvement on embodiment 1, and repeated content will not be described again.

[0099] In this embodiment, the InSAR-based measurement method can be used for settlement monitoring in key infrastructure areas, which include areas containing key infrastructure such as dams, bridges, and / or airports. Preferably, when monitoring settlement / subsidence in key infrastructure areas, several targets can be arranged in the key infrastructure areas according to the following rules: There exists at least one set of targets, wherein the geometric center of the geometry formed by all targets in this set coincides with the geometric center of the geometry formed by all targets in another set of targets, and there are no common targets in the two sets of targets.

[0100] Preferably, when conducting settlement monitoring in key infrastructure areas, one can select... Figure 6 The corner reflectors are arranged in method (c). The general principle is that any four points (up, down, left, and right) should form a rectangle or parallelogram, and the geometric centers of these rectangles or parallelograms must coincide. Simultaneously, the interference between two points and the principle of spatial difference can be used to solve the problem of phase integer ambiguity. The number and spacing of the corner reflectors increase with the required accuracy; the spacing between the corner reflectors can be selected from 10m to 500m. Preferably, the elevation and azimuth angles of the corner reflectors are determined based on the actual situation.

[0101] Preferably, such as Figure 6As shown in (c), six targets (i.e., target one, target two, target three, target four, target five, and target six) can be deployed in the key infrastructure area. Each target can have a corresponding phase value (i.e., P1, P2, P3, P4, P5, and P6). The lines connecting target one and target four, target two and target five, and target three and target six intersect at one point. Furthermore, the lines connecting target one and target five intersect at one point with the lines connecting target two and target six, and the lines connecting target two and target four intersect at one point with the lines connecting target three and target five.

[0102] Preferably, the location where the geometric centers coincide can be the intersection of the line segment connecting the first and fourth targets belonging to one set of targets, the line segment connecting the second and fifth targets belonging to another set of targets, and the line segment connecting the third and sixth targets belonging to yet another set of targets.

[0103] Preferably, in step S3, the phase value of the geometric feature point of the monitored object can be obtained by spatially differencing the phase value of each corner reflector feature point set in the corner reflector deployment area whose geometric center coincides with the geometric center of the monitored object. For the settlement / subsidence monitoring process of key infrastructure areas, the phase value of the corner reflector geometric feature point can be calculated according to the following formula: or .

[0104] Example 6 This embodiment is a further improvement on embodiment 1, and repeated content will not be described again.

[0105] In this embodiment, the InSAR-based measurement method can be used for settlement monitoring within a defined area, which is an area that needs to be demarcated, including building complexes and / or seismic zones, especially a large area. Preferably, when monitoring settlement / subsidence within a defined area, several targets can be arranged in the defined area according to the following rules: There exists at least one set of targets, wherein the geometric center of the geometry formed by all targets in this set coincides with the geometric center of the geometry formed by all targets in another set of targets, and there are no common targets in the two sets of targets.

[0106] Preferably, when conducting settlement monitoring within a defined area, one can select... Figure 6The corner reflectors are arranged in method (d). The general principle is a regular hexagonal arrangement, where any four points (top, bottom, left, and right) form rectangles or parallelograms. The geometric centers of these rectangles or parallelograms must coincide. Simultaneously, the interference between two points and the principle of spatial difference can be used to solve the problem of phase integer ambiguity. The number and spacing of the corner reflectors increase with the required accuracy. The spacing between adjacent corner reflectors can be selected from 10m to 500m. Preferably, the elevation and azimuth angles of the corner reflectors are determined based on the actual situation.

[0107] Preferably, such as Figure 6 As shown in (d), seven targets (i.e., the first target, the second target, the third target, the fourth target, the fifth target, the sixth target, and the seventh target) are deployed within a defined area. Each target may have a corresponding phase value (i.e., P1, P2, P3, P4, P5, P6, and P7). The lines connecting the first and fourth targets, the second and fifth targets, the third and sixth targets, and the location of the seventh target intersect at one point. Furthermore, in the current situation, multiple intersection points may exist; for example, the line connecting the first and seventh targets intersects with the line connecting the second and sixth targets. These are not listed here.

[0108] Preferably, the location where the geometric centers coincide can be: the intersection of the line segment connecting the first and fourth targets, the line segment connecting the second and fifth targets, the line segment connecting the third and sixth targets, and the location of the seventh target.

[0109] Preferably, in step S3, the phase value of the geometric feature point of the monitored object can be obtained by spatially differencing the phase value of each corner reflector feature point in the corner reflector deployment area whose geometric center coincides with the geometric center of the monitored object. For the settlement / subsidence monitoring process within a defined area, the phase value of the corner reflector geometric feature point can be calculated according to the following formula: .

[0110] Example 7 This embodiment is a preferred implementation of the foregoing embodiments, and repeated content will not be described again.

[0111] According to a preferred embodiment, the following is an implementation scheme of the present invention for monitoring corner reflectors deployed in a certain area.

[0112] Four corner reflectors were deployed at the four corner points of a rectangular area, with an east-west spacing of 20m and a north-south spacing of 40m. The deployment information of the corner reflectors on site is shown in the SAR image. Figure 7 and Figure 8The experiment used SAR satellite data with a resolution of 3m to monitor deformation in the region. The SAR satellite data parameters are shown in Table 1.

[0113] Table 1 SAR data parameters in the experiment Satellite type SAR satellite Track type Up rail, down rail Observation angle Left and right views Spatial resolution 3m Imaging mode strip polarization mode VV Number of images 10 Monitoring start time 2023-09-08 Monitoring termination time 2023-09-22 Step 1: The real and imaginary information in the SLC image is traversed, and two-dimensional fast Fourier transform is performed on each to complete the time-domain to frequency-domain calculation, so as to accurately identify the center of the corner reflector. Zero-filling interpolation is performed on the center point of the corner reflector, and the image is stretched by 256 times.

[0114] Step Two: Two-dimensional inverse fast Fourier transforms are performed on the real and imaginary parts of the interpolated SLC image respectively to complete the frequency domain to time domain conversion calculation.

[0115] Step 3: Calculate the phase of the center point and the phase of the geometric center point of the corner reflector in different SAR images. The location of the corner reflector in the SAR image captured on September 8, 2023 is shown below. Figure 2 As shown.

[0116] Step Four: Phase information of the geometric center point of the monitoring area in the 10 SAR images acquired in the experiment was calculated, and the slant range ΔL of each image was calculated and compared with the slant range ΔL obtained from ground measurement. The standard deviation of the measured slant range ΔL was 0.5157 mm. The regional deformation monitoring results are shown in Table 2. As can be seen from Table 2, the difference between the slant range ΔL calculated from the images and the slant range ΔL obtained from ground measurement is within the millimeter range. The experimental results show that the present invention can achieve high-precision deformation measurement of the monitoring area.

[0117] Table 2 Deformation Measurement Results

[0118] It should be noted that the specific embodiments described above are exemplary. Those skilled in the art can devise various solutions inspired by the disclosure of this invention, and these solutions all fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification and its accompanying drawings are illustrative and do not constitute a limitation on the claims. The scope of protection of this invention is defined by the claims and their equivalents. This specification contains multiple inventive concepts; terms such as "preferredly," "according to a preferred embodiment," or "optionally" indicate that the corresponding paragraph discloses an independent concept. The applicant reserves the right to file divisional applications based on each inventive concept. Throughout the text, the feature introduced by "preferredly" is only an optional approach and should not be construed as mandatory. Therefore, the applicant reserves the right to abandon or delete the relevant preferred feature at any time.

Claims

1. A method of measuring based on interferometric synthetic aperture radar (InSAR), characterized in that The measurement method comprises the following steps: determining prior positions of a plurality of targets and providing the prior positions to a ground processing unit (100); photographing an area where the plurality of targets are located by using a SAR satellite and sending data obtained by photographing to the ground processing unit (100); determining phase differences between the targets for single photographing of the targets; calculating slant ranges between the targets by using the ground processing unit (100) according to the phase differences determined in the above steps and a load wavelength of the SAR satellite; and determining a positional relationship between the targets by using the ground processing unit (100) according to the slant ranges and satellite orbit information, wherein, in single measurement, one-dimensional positional relationships between the targets are determined to obtain relative distance information between the targets; in multiple measurements, three-dimensional positional relationships between the targets are determined.

2. The measurement method according to claim 1, characterized in that, "Determining phase differences between the targets for single photographing of the targets" comprises: processing "SAR echo data photographed for the area where the targets are located" by the ground processing unit (100) to form a single look complex (SLC) image product containing amplitude and phase information of the photographed area; calculating phase information of coordinate points where amplitude maximum values of each of the targets are located by using a Sinc interpolation method in the single look complex image product; and calculating phase differences between the targets by using the ground processing unit (100) according to the phase information of each of the targets.

3. The measuring method according to claim 1 or 2, characterized in that, "The coordinate points where amplitude maximum values of each of the targets are located" are coordinate points where amplitude maximum values located near prior positions of the corresponding targets after Sinc interpolation, so that phase information of each of the targets is determined from the single look complex image product after Sinc interpolation.

4. The measuring method according to any one of claims 1 to 3, characterized in that, "Determining a positional relationship between the targets by using the ground processing unit (100) according to the slant ranges and satellite orbit information" comprises: in the case of photographing by the SAR satellite "at least once in a specified time period", obtaining one-dimensional deformation information by analyzing one-dimensional positional relationship difference values between at least two groups of photographed targets; in the case of photographing by the SAR satellite "at least twice in a specified time period", obtaining two-dimensional deformation information by analyzing two-dimensional positional relationship difference values between at least two groups of photographed targets; and in the case of photographing by the SAR satellite "at least three times in a specified time period", obtaining three-dimensional deformation information by analyzing three-dimensional positional relationship difference values between at least two groups of photographed targets.

5. The measuring method according to any one of claims 1 to 4, characterized in that, The area photographed by using the SAR satellite at least includes a plurality of the targets arranged in a specific rule, and arrangement positions of at least part of the targets are correlated with each other, so that a specific geometric shape formed by the part of the targets with the correlated arrangement positions has corresponding geometric feature points.

6. An interferometric synthetic aperture radar (InSAR) based measurement system, characterized in that The measurement system at least includes a ground processing unit (100) for processing data and an acquisition unit (200) arranged on a SAR satellite, wherein the ground processing unit (100) is configured to receive determined prior positions of a plurality of targets; The acquisition unit (200) on the SAR satellite photographs the area where the targets are located and sends the data obtained by the photographing to the ground processing unit (100); The ground processing unit (100) determines the phase difference between the targets according to the single photographing of the targets; The ground processing unit (100) calculates the slant range between the targets according to the determined phase difference and the load wavelength of the SAR satellite; and The ground processing unit (100) determines the positional relationship between the targets according to the slant range and the satellite orbit information, wherein, in single measurement, one-dimensional positional relationship between the targets, i.e. relative distance information between the targets, is determined; in multiple measurements, three-dimensional positional relationship between the targets is determined.

7. The measurement system of claim 6, wherein, The ground processing unit (100) processes the SAR echo data photographed for the area where the targets are located to form a single look complex image product (SLC) containing the amplitude and phase information of the photographed area when determining the phase difference between the targets; The ground processing unit (100) calculates the phase information of the coordinate point where the amplitude maximum value of each target is located by using the Sinc interpolation method in the single look complex image product; and The ground processing unit (100) calculates the phase difference between the targets according to the phase information of each target.

8. The measuring system according to claim 6 or 7, characterized in that The "coordinate point where the amplitude maximum value of each target is located" determined by the ground processing unit (100) is the coordinate point where the amplitude maximum value is located near the prior position of the corresponding target after Sinc interpolation, so as to determine the phase information of each target from the single look complex image product after Sinc interpolation.

9. The measuring system according to any of claims 6 to 8, characterized in that In the case of photographing by the acquisition unit (200) on the SAR satellite "at least once within a specified time period", the ground processing unit (100) obtains one-dimensional deformation information by analyzing the one-dimensional positional relationship difference between at least two groups of photographed targets; In the case of photographing by the acquisition unit (200) on the SAR satellite "at least twice within a specified time period", the ground processing unit (100) obtains two-dimensional deformation information by analyzing the two-dimensional positional relationship difference between at least two groups of photographed targets; And In the case of photographing by the acquisition unit (200) on the SAR satellite "at least three times within a specified time period", the ground processing unit (100) obtains three-dimensional deformation information by analyzing the three-dimensional positional relationship difference between at least two groups of photographed targets.

10. The measuring system according to any of claims 6 to 9, characterized in that The measurement system comprises a plurality of reflection units (300) arranged in a specific rule to serve as the targets photographed by the acquisition unit (200), wherein the arrangement positions of at least part of the reflection units (300) are correlated with each other, so that the specific geometric shape formed by the part of the reflection units (300) having the correlated arrangement positions has corresponding geometric feature points.

11. Use of an interferometric synthetic aperture radar (InSAR) based measuring method according to any one of claims 1 to 5 for subsidence / settlement monitoring, characterized in that The monomer building area to be monitored, the linear engineering area, the key infrastructure area and / or the limited range area can be arranged with a plurality of targets in a specific arrangement rule to implement the measurement method based on InSAR (Interferometric Synthetic Aperture Radar).

12. Use according to claim 11, characterized in that, In the single building area, the targets are arranged according to the following rules: There are at least two target groups, the geometric center of the geometric shape formed by all the targets in one group coincides with the geometric center of the geometric shape formed by all the targets in another group, and there is no common target in the two target groups, and the position of the geometric center coincidence is: The intersection point of the line segment formed by the first target and the third target belonging to one target group and the line segment formed by the second target and the fourth target belonging to another target group.

13. Use according to claim 11 or 12, characterized in that, In the linear engineering area, the targets are arranged according to the following rules: There are at least two target groups, the geometric center of the geometric shape formed by all the targets in one group coincides with the geometric center of the geometric shape formed by all the targets in another group, and there is no common target in the two target groups, and the position of the geometric center coincidence is: The intersection point of the line segment formed by the first target and the third target belonging to one target group and the point where the second target belonging to another target group is located.

14. The use according to any one of claims 11 to 13, characterized in that, In the key infrastructure area, the targets are arranged according to the following rules: There are at least two target groups, the geometric center of the geometric shape formed by all the targets in one group coincides with the geometric center of the geometric shape formed by all the targets in another group, and there is no common target in the two target groups, and the position of the geometric center coincidence is: The intersection point of the line segment formed by the first target and the fourth target belonging to one target group, the line segment formed by the second target and the fifth target belonging to another target group, and the line segment formed by the third target and the sixth target belonging to another target group.

15. The application according to any one of claims 11 to 14, characterized in that, In the limited range area, the targets are arranged according to the following rules: There are at least two target groups, the geometric center of the geometric shape formed by all the targets in one group coincides with the geometric center of the geometric shape formed by all the targets in another group, and there is no common target in the two target groups, and the position of the geometric center coincidence is: The intersection point of the line segment formed by the first target and the fourth target, the line segment formed by the second target and the fifth target, the line segment formed by the third target and the sixth target, and the point where the seventh target is located.

Images