A foundation sar environment error correction method and device

Abstract

The application provides a foundation SAR environment error correction method and device, comprising: taking a radar reflector as a reference target for radiation calibration of the foundation SAR, and obtaining reference datum; obtaining accumulated original displacement data of the foundation SAR, and comparing and verifying the reference datum; reading real-time meteorological element data, vibration data and position data of a monitoring point; establishing an atmospheric refractive index model based on the meteorological element data, and calculating atmospheric effect error; calculating offset error through the vibration data; obtaining environment correction error based on the offset error and the atmospheric effect error; obtaining corrected foundation SAR data based on the environment correction error; and comparing and verifying the corrected foundation SAR data with the reference datum. The scheme combines meteorological data with vibration data, displacement data and the like, has good environment error correction precision and feasibility, and can verify the accuracy of correction through the reference datum of the device, and provides a basis for slope stability analysis of a monitoring area.

Description

Technical Field

[0001] This invention relates to the fields of geological monitoring and natural disaster monitoring, and in particular to a ground-based SAR environmental error correction method and device. Background Technology

[0002] Existing landslide deformation monitoring technologies have many shortcomings in landslide monitoring. Ground-based synthetic aperture interferometry (GSAR) technology, which has emerged in recent years, can continuously monitor large areas around the clock, in all weather conditions, over long distances, and with high precision. It has already demonstrated enormous application prospects and economic value in landslide deformation monitoring, thus opening a new chapter in this field. Conducting research on ground-based SAR deformation monitoring will help promote its application in landslide deformation monitoring and is of great significance for landslide prevention and mitigation.

[0003] Ground-based SAR, as an active remote sensing technology, acquires target location and motion information by transmitting and receiving electromagnetic waves. Under ideal monitoring conditions, ground-based SAR deformation monitoring has high accuracy. However, in actual monitoring, it is affected by many environmental factors, which reduces the accuracy and reliability of the monitoring. First, during the propagation of electromagnetic waves in the atmosphere, the propagation direction is deflected due to the non-uniform atmospheric medium, resulting in a delay in propagation time and a curved propagation path. In ground-based SAR deformation monitoring research, the electromagnetic waves are inevitably affected by atmospheric refraction during propagation, causing their propagation path to bend and delaying the reception of echo signals by the receiving antenna. Ground-based SAR is also highly sensitive to weather changes during the monitoring period, especially changes in atmospheric humidity. Under conditions of a monitoring distance of 1 km and a monitoring area temperature of 20°C, a 1% change in relative humidity (RH) can cause ground-based radar observation errors to reach the millimeter level. Errors caused by atmospheric effects severely reduce the deformation monitoring accuracy of ground-based radar. The electromagnetic wave signals transmitted by ground-based SAR are affected by atmospheric effects, resulting in atmospheric phase errors, which reduce the accuracy and reliability of ground-based SAR monitoring results. Currently, there is no unified atmospheric correction method for ground-based radar in this field. Various atmospheric correction methods coexist, but systematic theoretical analysis and experimental verification are lacking. Therefore, it is necessary to conduct accuracy assessment and universality comparison of commonly used atmospheric correction methods in order to more reasonably correct errors.

[0004] Secondly, in ground-based SAR deformation monitoring research, in addition to errors caused by atmospheric effects, there is also the influence of surface environmental offset errors. Surface platforms are extremely prone to a series of small and highly random phase shifts, especially in the acquired vibration signals. These vibration signals often interfere with the real signal, causing deviations in the real signal, resulting in a decrease in the signal-to-noise ratio, affecting the coherence of the phase data map, and severely impacting monitoring accuracy and precision. Ground-based SAR itself is a long-term monitoring device, and the influence of environmental errors inevitably has a significant impact on the reliability of ground-based SAR monitoring. Furthermore, the accuracy of ground-based SAR in monitoring slope deformation also requires data comparison and verification. Currently, there are no devices on the market for comparing and verifying ground-based SAR data, which means that ground-based SAR data cannot be compared, its accuracy cannot be verified, and radar data errors cannot be accurately analyzed and corrected. Therefore, how to more rationally consider multiple factors and correct for environmental errors is also an urgent problem to be solved. Summary of the Invention

[0005] In view of the problems existing in the prior art, this invention corrects environmental errors by combining atmospheric effects and surface environmental offset errors, so as to ensure the accuracy and reliability of monitoring results. Specifically, this invention provides the following technical solution:

[0006] On the one hand, the present invention provides a ground-based SAR environmental error correction method, the method comprising:

[0007] S1. Using the radar reflector as the reference target for ground-based SAR radiation calibration, read the static cumulative displacement data and dynamic cumulative displacement data as reference benchmark data, and upload them to the cloud platform.

[0008] S2. Ground-based SAR acquires echo data from radar reflectors, and then performs interferometric processing to obtain the accumulated raw displacement data;

[0009] S3. Read real-time meteorological data, vibration data, and location data from the monitoring point and upload them to the cloud platform;

[0010] S4. Establish an atmospheric refractive index model based on the meteorological element data and calculate the atmospheric effect error; calculate the offset error using vibration data; obtain the environmental correction error based on the offset error and the atmospheric effect error.

[0011] S5. Based on environmental correction error, perform environmental error correction on the original displacement data to obtain the corrected ground-based SAR data; compare and verify the corrected ground-based SAR data with the reference benchmark data.

[0012] Preferably, the meteorological data includes wind speed, wind direction, temperature, humidity, air pressure, and rainfall.

[0013] Preferably, the atmospheric refractive index model is:

[0014]

[0015] Where e represents humidity, T represents temperature, and P represents temperature. d N represents atmospheric pressure, and N represents the atmospheric refractive index.

[0016] Preferably, the atmospheric effect error Δd is:

[0017] Δd=ΔNR s

[0018] Where ΔN is the relative change in atmospheric refractive index between the two sampling intervals, and R s It is the distance from the electromagnetic wave emission point to the target point.

[0019] Preferably, the specific method for calculating the offset error is as follows:

[0020] S401. Samples are taken at time intervals equal to the ground-based SAR acquisition period to obtain measured vibration data x. k Where k = 1, 2, 3, ..., n, and n represents the number of samples;

[0021] S402, Using an m-order polynomial X K Fitting the measured vibration data, we have:

[0022] X K =a0+a1k+a2k 2 +...+a m k m k = 1, 2, 3, ..., n;

[0023] S403. Select m=3, perform polynomial trend term elimination, and screen polynomial coefficients to ensure that X k With x k The formula for eliminating the linear trend term is obtained by minimizing the sum of squared differences:

[0024] y = x k -X k =x k -(a0-a1k);

[0025] S404, Calculate the offset error d:

[0026]

[0027] in, These are the phases obtained from two consecutive samples, and λ is the wavelength of the ground-based SAR.

[0028] Preferably, the environmental correction error D is:

[0029]

[0030] Where, d i Let Δd represent the offset error of the i-th sample. i Let y represent the atmospheric effect error of the i-th sampling. i This represents the formula for eliminating the linear trend term in the i-th sample, where n represents the number of samples.

[0031] Preferably, in S5, the comparison and verification method is as follows:

[0032] S501. At the monitoring point, the radar reflector is moved at intervals of g steps toward the radar line of sight, with a single step size of f, and dynamic cumulative displacement data is collected; the interval duration is consistent with the ground-based SAR acquisition cycle.

[0033] S502. After completing g steps, remain stationary for g intervals and collect static cumulative displacement data.

[0034] S503. Use the data from S501 and S502 as reference data, obtain the original cumulative displacement data of the ground-based SAR, and correct the original cumulative displacement data to obtain the corrected ground-based SAR data.

[0035] S504. Compare the corrected ground-based SAR data with the reference benchmark data to verify the accuracy of the corrected data.

[0036] On the other hand, the present invention also provides a ground-based SAR environmental error correction device for performing the method described above, the device comprising:

[0037] Radar reflector, weather station terminal module, tilt vibration sensor, positioning system, 4G communication module, weather sensor, electric displacement stage, bracket, integrated protective box; the device communicates with the cloud platform to transmit or receive data;

[0038] The radar reflector is mounted on an electrically driven displacement platform, which is located at the lower part of the support to support the radar reflector for high-precision displacement. The radar reflector is used to reflect radar electromagnetic waves and serves as a reference target for ground-based SAR radiation calibration.

[0039] The meteorological sensor is mounted on the top of the support frame to collect meteorological element data; the meteorological station terminal module is connected to the meteorological sensor to output the meteorological element data to the background for real-time viewing.

[0040] The positioning system includes a high-precision positioning system receiver and a high-precision positioning system antenna; the high-precision positioning system receiver is used to acquire the device's position data and displacement data; the high-precision positioning system antenna is mounted on the top of the integrated protective box.

[0041] The integrated protective box is located in the middle of the bracket, and the meteorological station terminal module, 4G communication module and high-precision positioning system receiver are all located inside the integrated protective box;

[0042] The tilt vibration sensor is mounted on the electric displacement stage to detect vibration data and tilt data of the radar reflector.

[0043] Preferably, the device further includes a power module, a storage battery, and a solar power supply system;

[0044] The solar power supply system is located on the upper part of the bracket;

[0045] The power module and the battery are housed inside the integrated protective enclosure;

[0046] The power supply module provides power to the weather station terminal module, 4G communication module, positioning system, and electric displacement platform.

[0047] The battery is connected to the power module and the solar power system.

[0048] Preferably, the electric displacement stage is controlled by a stepper motor and driven by a ball screw.

[0049] Preferably, the device is fixed at the monitoring point during use;

[0050] The bracket is equipped with a fixing flange at its bottom.

[0051] Compared with the prior art, the technical solution of the present invention has at least the following advantages:

[0052] This scheme systematically combines surface environmental migration error with atmospheric error. Addressing the lack of systematic accuracy comparison and universality analysis among various correction methods, it employs a combination of theoretical and simulation experiments to analyze the accuracy and universality of environmental error correction methods. It improves upon the shortcomings of function fitting methods, such as atmospheric effect errors and difficulty in selecting control points, by combining meteorological, vibration, and displacement data. Simulation experiments demonstrate that this method has high accuracy and feasibility in environmental error correction.

[0053] Meanwhile, this solution integrates a radar reflector, a high-precision displacement stage, a weather station, a tilt vibration sensor, a high-precision positioning system (with static millimeter-level positioning capability), a 4G module, and a solar panel. The device is fixed to the target slope and equipped with a corner reflector with a large RCS, serving as a reference target for radiometric calibration. The tilt vibration sensor and high-precision positioning system record real-time displacement and vibration data from the corner reflector. Simultaneously, information such as temperature, humidity, and rainfall from the weather station is transmitted to the platform. By acquiring the information from the device, atmospheric correction is performed on the monitoring data according to the meteorological data correction method proposed in this patent. The results from this device are then used as a reference for correcting and verifying the ground-based SAR data, and the slope stability of the monitored area is analyzed. This undoubtedly has extraordinary significance for disaster prevention and mitigation in engineering projects. Attached Figure Description

[0054] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0055] Figure 1 This is a flowchart of a method according to an embodiment of the present invention;

[0056] Figure 2 This is a side view of the error correction device according to an embodiment of the present invention;

[0057] Figure 3 This is a front view of the error correction device according to an embodiment of the present invention;

[0058] Figure 4 This is a ground-based SAR imaging image according to an embodiment of the present invention;

[0059] Figure 5 This is a comparison diagram of the reflection intensity between the device and the environment in an embodiment of the present invention;

[0060] Figure 6 This is a schematic diagram of the ideal displacement curve in an embodiment of the present invention;

[0061] Figure 7 This is the original displacement curve diagram without environmental error correction in an embodiment of the present invention;

[0062] Figure 8 This is a displacement curve diagram showing the completion of environmental error correction according to an embodiment of the present invention.

[0063] The attached figures are numbered as follows: 1-Radar reflector, 2-Meteorological sensor, 3-Integrated protective box, 4-Meteorological station terminal module, 5-4G communication module, 6-High-precision positioning system receiver, 7-High-precision positioning system antenna, 8-Tilting vibration sensor, 9-Power module, 10-Battery, 11-Solar power supply system, 12-Electric displacement stage, 13-Support. Detailed Implementation

[0064] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0065] Those skilled in the art should understand that the following specific embodiments or implementation methods are a series of optimized configurations listed to further explain the specific content of the invention. These configuration methods can be combined or used in conjunction with each other, unless the invention explicitly states that some or a specific embodiment or implementation method cannot be associated with or used in conjunction with other embodiments or implementation methods. Furthermore, the following specific embodiments or implementation methods are merely optimized configurations and are not intended to limit the scope of protection of the invention.

[0066] Combination Figure 1 As shown, this invention corrects environmental errors by combining atmospheric effects and surface environmental offset errors. The purpose is to provide a ground-based SAR environmental error correction method and device that records slope stability and environmental conditions in real time. It can be used to verify the accuracy of ground-based SAR data and to analyze and correct environmental errors in ground-based SAR.

[0067] Step 1: Using a radar reflector as the reference target for ground-based SAR radiometric calibration, we set up the ground-based SAR system on the same horizontal line as the reference target and began collecting data. We read the static data of the corner reflector when it was stationary, and the dynamic cumulative displacement data when it was moving. This data was then uploaded to the cloud platform to obtain the real data from the monitoring point, which will serve as the benchmark data for subsequent comparisons. Ground-based SAR was used for data collection at the monitoring point.

[0068] Step 2: Read the cumulative displacement data from the ground-based SAR and compare it with the data from the monitoring point devices uploaded to the platform for verification. There will inevitably be a certain error between the target displacement data acquired by the ground-based SAR and the actual displacement data of the monitoring point. When the radar monitoring data is correct, this error is considered an environmental error. To verify the monitoring accuracy of the ground-based SAR and to correct for environmental errors, this error correction device was invented. The device has an electric displacement stage with a unidirectional positioning accuracy of less than 10µm, a repeatability accuracy of up to 1µm, and capable of supporting corner reflectors for high-precision displacement. It simulates target deformation by setting the electric displacement stage to move 10 steps at equal intervals in the direction of the radar line of sight. The distance of each step is 0.5mm, and the interval between each step is set to be consistent with the ground-based SAR acquisition cycle. After completing 10 steps of displacement, the device remains stationary. This is repeated 10 times in the stationary state. Ideally, the cumulative displacement curve of the device shows an increasing trend from 0-5mm, followed by a 5mm stationary state. This data can be considered the actual displacement data and used as a reference baseline.

[0069] In the simulation scheme, ground-based SAR synchronously acquires data. At this time, the original cumulative displacement monitoring results acquired by ground-based SAR are compared with the real reference data. Then, the cumulative displacement monitoring results of ground-based SAR after environmental error correction are compared with the reference data to verify the accuracy and reliability of the environmental error correction algorithm.

[0070] The high-precision displacement angle reflector in the device returns static and dynamic real-time displacement data. The ground-based SAR synchronously obtains the corresponding echo data. By interferometric processing of the echo data, the cumulative original displacement data is obtained.

[0071] Step 3: Read real-time meteorological data such as wind speed and direction, temperature and humidity, air pressure, and rainfall from the slope monitoring point through the error correction device, and obtain the vibration and location information of the device, and upload it to the cloud platform.

[0072] Step 4: Establish an atmospheric refractive index model using meteorological observation data, calculate atmospheric effect error using meteorological data correction method; and calculate offset error based on least squares theory using acquired vibration data information combined with high-precision position change data.

[0073] Electromagnetic waves undergo refraction due to differences in the atmospheric medium along their propagation path. Because of the complexity of atmospheric medium distribution in space, electromagnetic waves emitted by satellites experience multiple atmospheric refractions during propagation. The meteorological data correction method models the temperature, humidity, and air pressure information of the monitored area, calculating the temporal variation of atmospheric refractive index to eliminate atmospheric effect errors in ground-based radar signals. Since the meteorological data correction method assumes uniform atmospheric variation, it is suitable for use in small-scale ground-based radar monitoring. With the support of high-precision meteorological data, the accuracy of the meteorological data correction method is better than millimeter-level. Because the atmospheric correction accuracy of the meteorological data correction method is directly related to the accuracy of the meteorological data, the advent of high-precision meteorological instruments has provided favorable conditions for the implementation of this method.

[0074] In the field of radio frequency, we can obtain the model for the atmospheric refractive index N as follows:

[0075]

[0076] Where e represents relative humidity, T represents measured temperature, and P represents relative humidity. d This represents atmospheric pressure. In actual measurements, the measured temperature T, relative humidity e, and atmospheric pressure P are used to obtain these values. d The atmospheric refractive index can be calculated from the meteorological data of these three parameters. In ground-based SAR deformation monitoring, the atmospheric medium can be assumed to be uniformly distributed, and the relative change in atmospheric refractive index between two sampling intervals is ΔN. When the electromagnetic wave reaches the target point at a distance of Rs and then returns, the impact on atmospheric effect error can be equivalently represented as:

[0077] Δd=ΔN·Rs

[0078] △d represents the atmospheric effect error that needs to be removed from ground-based SAR.

[0079] The aforementioned meteorological data correction methods also have certain limitations. They are difficult to implement with spaceborne InSAR. Firstly, the monitoring area is vast, and atmospheric refractive index varies significantly at different locations, making it difficult to acquire meteorological data for the entire region using meteorological equipment. Secondly, spaceborne InSAR operates in orbits hundreds of kilometers above the ground, and the electromagnetic waves emitted by the satellite undergo complex atmospheric refraction due to temporal and spatial variations in the atmospheric medium during propagation, making modeling difficult. In contrast, ground-based SAR signals propagate in the troposphere. In short-range, small-area regions, the terrain gradient changes less, and the atmospheric refractive index can be considered the same at all points at the same time, varying only over time. This provides theoretical feasibility for ground-based radar meteorological data correction methods.

[0080] In addition to errors caused by atmospheric effects, surface environment offset errors also exist in actual monitoring. Surface platforms are extremely prone to a series of small and highly random phase shifts, especially in the acquired vibration signals. These vibration signals often interfere with the real signal, causing the real signal to deviate, resulting in a decrease in the signal-to-noise ratio, affecting the coherence of the phase data map, and severely impacting monitoring accuracy and precision. Vibration signal interference processing mainly involves eliminating interference components in the ground-based SAR acquired data, while also performing appropriate data smoothing on the original signal. In this embodiment, we acquire vibration signals using a combined tilt vibration monitoring sensor and employ the least squares method to eliminate vibration signal interference. The least squares method can eliminate both linear trend terms and nonlinear high-order polynomial trend terms in the signal. Specifically:

[0081] Sampling was performed according to the time interval of the ground-based SAR acquisition cycle, and the sampled data x of the measured vibration signal were obtained. k (k = 12, 3, ..., n) Samples are taken at equal time intervals, where n represents the total number of samples, and the sampling time interval Δt = radar sampling frequency. Assume an m-order polynomial X is used. K To fit the actual sampled signal, we have:

[0082] X K =a0+a1k+a2k 2 +...+a m k m (k = 1, 2, 3, ..., n)

[0083] We selected m=3 to perform polynomial trend term elimination processing on the ground-based SAR data.

[0084] Based on the principle of least squares, choose appropriate polynomial coefficients a o a1, a2...a m Make X k With x k The formula for eliminating the linear trend term is obtained by minimizing the sum of squared differences:

[0085] y = x k -X k =x k -(a0-a1k)(k=1,2,3,...,n)

[0086] In this scheme, ground-based SAR employs interferometric measurement technology, which obtains the deformation amount by monitoring the phase difference between two consecutive samples of the deformed body. Assuming the deformation amount in the line-of-sight direction is d, and the phases obtained from two adjacent samples are φ1 and φ2 respectively, and the wavelength of the ground-based SAR is λ, then the offset error d is:

[0087]

[0088] By combining the surface environmental offset error with the atmospheric error, we can obtain the environmental correction error D as follows:

[0089]

[0090] Step 5: Complete environmental error correction. Compare and verify the accuracy of the correction by comparing the corrected ground-based SAR data with the actual data from the monitoring point device.

[0091] In step five, error correction is completed. This mainly involves obtaining cumulative raw displacement data from the echo data acquired by ground-based SAR through interferometry. The cumulative raw displacement data is then corrected using the environmental correction error obtained in step four, thus obtaining the corrected ground-based SAR data.

[0092] Environmental error correction is completed, and the corrected ground-based SAR data is compared and verified with the actual reference data of the monitoring point device. The displacement accumulation curve of the reference data shows an initial increase of 0-5mm, followed by a static state. Ideally, the corrected ground-based SAR data should be consistent with the reference data, with an acceptable error range within 0.1mm. Through the above comparison, the accuracy and reliability of the correction can be evaluated. In a specific embodiment, adapted to the above correction method, the present invention also provides a ground-based SAR environmental error correction device, combined with... Figure 2 , Figure 3 As shown, this device integrates a multi-faceted radar reflector 1, a meteorological station terminal module 4, an angle vibration sensor 8, a high-precision positioning system (static centimeter-level positioning capability), a 4G communication module 5, and a solar power supply system 11. The device is fixed to the target slope and equipped with an integrated corner reflector with a large RCS, serving as a reference target for ground-based SAR radiometric calibration to verify slope stability. The device integrates an angle vibration sensor and a high-precision positioning system, which can record and upload real-time displacement and vibration data to a cloud platform. The acquired data is used for comparison and verification with data obtained from ground-based SAR. Simultaneously, the device integrates an ultrasonic meteorological station, which can transmit six types of environmental meteorological information—temperature, humidity, wind speed, wind direction, air pressure, and rainfall—to the cloud platform in real time. By utilizing the accurate environmental meteorological information acquired from the device, along with monitoring point data under the influence of atmospheric environmental changes, and combining the device's results as a reference, ground-based SAR data is corrected and verified, and the slope stability of the monitored area is analyzed. By combining radar data under static monitoring with target vibration, displacement, and meteorological information, a data model is established. Then, through comparative experiments with data under dynamic monitoring, measurement errors caused by the environment can be effectively corrected, improving the accuracy and reliability of target measurements. This undoubtedly plays a crucial role in the research of atmospheric correction methods for ground-based SAR.

[0093] The device mainly consists of the following parts:

[0094] 1. Radar reflector, also known as a corner reflector, consists of several metal plates that intersect to form a geometric shape that strongly reflects radar signals. When radar electromagnetic waves scan the corner reflection, the electromagnetic waves are refracted and amplified at the metal corners. Especially when these metal plates intersect at a 90° angle, a very strong echo signal is generated. The reflector is made of aluminum alloy, with each surface intersecting at a 90° angle. Each reflective surface is smooth and has a natural-colored anodized finish. The electromagnetic waves are refracted and amplified at the metal corners, generating a strong echo signal that serves as a reference target for ground-based SAR, enabling precise detection of the device within a range of several kilometers.

[0095] 2. An integrated ultrasonic weather sensor, wherein the weather sensor 2 is a highly integrated, low-power, high-precision automatic weather observation module capable of real-time observation of six meteorological elements: wind speed, wind direction, temperature, humidity, air pressure, and rainfall. It has an IP65 protection rating and can achieve 24-hour continuous online monitoring of outdoor meteorological parameters. The weather sensor 2 is mounted on the top of the support frame.

[0096] 3. An integrated protective box 3, comprising a power module 9, a weather station terminal module 4, a 4G communication module 5, a storage battery 10, and a high-precision positioning system receiver 6, with an IP66 protection rating. The integrated protective box 3 is located in the middle of the support frame.

[0097] 4. Weather station terminal module: The weather station terminal module 4 is connected to the weather sensor 2 and can output six meteorological parameters, namely wind speed, wind direction, temperature, humidity, air pressure and rainfall, to the background at one time through the digital communication interface, and the data can be viewed in real time.

[0098] 5.4G communication module: The 4G communication module 5 is fixed inside the integrated protective box 3. It is an industrial-grade 4G module that supports the 4G networks of the three major operators. It has the advantages of high speed, low latency and wide coverage, and can transmit meteorological module data and positioning system data back to the platform in real time.

[0099] 6. High-precision positioning system receiver: The high-precision positioning receiver 6 is fixed inside the integrated protective box 3. It is a centimeter-level positioning system with a horizontal positioning accuracy of about 2 cm and an elevation accuracy of 5 cm. It has a high degree of integration, low power consumption, and can acquire the positioning and displacement information of the device in real time.

[0100] 7. High-precision positioning system antenna 7, which is a high-gain positioning antenna with strong reception, high gain, and low power consumption, and uses a magnetic base for stability and resistance to displacement. The high-precision positioning system antenna 7 is mounted on the top of the integrated protective box.

[0101] 8. Tilt vibration sensor 8 is a three-axis tilt and vibration monitoring sensor that integrates data acquisition, wireless communication, power supply, and self-protection. The overall protection level reaches IP68, making it suitable for harsh outdoor natural environments. It uses a lithium-ion battery for continuous power supply for 60 months. The tilt vibration sensor 8 is set on the electric displacement stage 12. Its main function is to measure the tilt and vibration changes of the radar reflector 1 in real time and upload the data information to the cloud platform in real time.

[0102] 9. Power supply module 9, fixed inside the integrated protective box 3, is mainly responsible for powering other modules. It can output four 12V voltages to power the meteorological station terminal module, 4G communication module 5, high-precision positioning system, and electric displacement stage 12 respectively. The high-precision positioning system consists of a high-precision positioning system receiver and a high-precision positioning system antenna. The antenna is outside the box, and the receiver is inside the box. The antenna locates the position information and feeds it back to the receiver to obtain real-time position information.

[0103] 10. Storage battery, wherein the storage battery 10 may be configured as, for example, a 100AH ​​lithium battery, fixed in the integrated protective box 3, the battery having an input interface and an output interface, the input interface being connected to a solar panel for charging, and the input interface being connected to a power module 9.

[0104] 11. A solar power supply system, wherein the solar power supply system 11 is a high-conversion-rate monocrystalline silicon solar panel with a power of 100W, and is equipped with a 100AH ​​lithium battery, which can meet the device's continuous uninterrupted operation for three consecutive cloudy and rainy days.

[0105] 12. An electric displacement stage 12, controlled by a two-phase stepper motor and guided by a ball screw, has a unidirectional positioning accuracy of less than 10µm, a repeatability of up to 1µm, a stroke of 100mm, and a table load capacity of up to 10kg, capable of supporting corner reflectors for high-precision displacement. The electric displacement stage 12 is located at the lower part of the support frame.

[0106] 13 Device bracket, the bracket 13 is made of carbon steel, is 3 meters long, the top does not need a flange and can directly fit the sensor, and the bottom has a fixed flange.

[0107] In practical use, this device can be directly positioned at various monitoring points on the slope of the area to be monitored to collect real-time data and assist in correcting environmental errors. Specifically, the ground-based lidar can be installed on a flat surface in an open area, ensuring there are no obstructions. The equipment should be connected and properly configured. Within the scanning range of the ground-based lidar's electromagnetic waves, the lidar emits radio frequency signals, which are radiated into space via the radar transmitting antenna. When the electromagnetic waves encounter the radar reflector, they are reflected. The echo signal is received by the ground-based lidar receiving antenna and reaches the receiver of the high-precision positioning system for information processing. This allows the acquisition of radar reflector parameters, including but not limited to distance, azimuth, velocity, and shape.

[0108] In another embodiment, to verify the monitoring accuracy of ground-based SAR, the device itself has an electric displacement stage with a unidirectional positioning accuracy of less than 10 μm and a repeatability accuracy of up to 1 μm, capable of carrying corner reflectors for high-precision displacement. The simulation scheme involves setting the electric displacement stage to move 10 steps at equal intervals in the radar line-of-sight direction. The distance of each step is 0.5 mm, and the interval between each step is set to be consistent with the ground-based SAR acquisition cycle. After completing 10 steps of displacement, the device remains stationary. This process is repeated 10 times in the stationary state. Ideally, the cumulative displacement curve of the device shows an increasing trend from 0 to 5 mm, followed by a 5 mm stationary position. This data is used as a reference baseline, and the cumulative displacement monitoring results of the ground-based SAR after environmental error correction are compared with the reference baseline data to verify the accuracy and reliability of the environmental error correction algorithm.

[0109] In a specific experiment, we set up the device on a mine 1500 meters away from the radar's line of sight. The device was at the same height as the radar, and the radar reflector surface was perpendicular to the aperture of the ground-based radar antenna. We then conducted a simulation experiment. Figure 4 This is a ground-based radar image, which clearly identifies the location of the device. Figure 5 By comparing the reflection intensity of a section of the mine slope and the device in the imaging image, it can be seen that the reflection intensity of the corner reflector inside the device is much higher than that of the surrounding environment, and the corner reflector can be clearly identified.

[0110] Figure 6 To set the actual ideal curve of the device's displacement according to the parameters, as a reference benchmark, where Figure 6 The upper diagram shows the location of the setting device, and the lower diagram shows the actual ideal curve. Figure 7 The raw cumulative displacement monitoring results obtained by the ground-based SAR monitoring device, from Figure 7The comparison of the times marked in the upper and lower figures shows that due to environmental errors, the displacement monitoring results obtained by the ground-based SAR fluctuated during the monitoring period. The cumulative displacement value error exceeded 1 mm, and the cumulative displacement error value in the static state also reached 0.5 mm. In order to improve the measurement accuracy and reliability, it is necessary to perform environmental error correction for environmental influences. Figure 8 This is the displacement monitoring result after environmental error correction, from Figure 8 The comparison of the time of the upper and lower figures and the key points shows that the cumulative displacement error is less than 0.2 mm, and the cumulative displacement error in the static state is less than 0.1 mm, which effectively improves the measurement accuracy and reliability of the ground-based SAR monitoring data.

[0111] In another embodiment, this solution can be implemented using a device, which may include corresponding modules that perform one or more steps in the various embodiments described above. Therefore, each or more steps in the various embodiments can be performed by a corresponding module, and the electronic device may include one or more of these modules. A module may be one or more hardware modules specifically configured to perform a corresponding step, or implemented by a processor configured to perform a corresponding step, or stored in a computer-readable medium for implementation by a processor, or implemented through some combination thereof.

[0112] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of this solution includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as will be understood by those skilled in the art to which the embodiments of this solution pertain. The processor performs the various methods and processes described above. For example, the method embodiments of this solution can be implemented as software programs tangibly contained in a machine-readable medium, such as memory. In some embodiments, part or all of the software program can be loaded and / or installed via memory and / or a communication interface. When the software program is loaded into memory and executed by the processor, one or more steps of the methods described above can be performed. Alternatively, in other embodiments, the processor can be configured to perform one of the methods described above by any other suitable means (e.g., by means of firmware).

[0113] The logic and / or steps represented in the flowchart or otherwise described herein may be specifically implemented in any readable storage medium for use by, or in conjunction with, an instruction execution system, apparatus or device (such as a computer-based system, a processor-included system or other system that can fetch and execute instructions from, an instruction execution system, apparatus or device).

[0114] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A ground-based SAR environmental error correction method, characterized in that, The method includes: S1. Using the radar reflector as the reference target for ground-based SAR radiation calibration, read the static cumulative displacement data and dynamic cumulative displacement data as reference benchmark data, and upload them to the cloud platform. S2. Ground-based SAR acquires echo data from radar reflectors, and then performs interferometric processing to obtain the accumulated raw displacement data; S3. Read real-time meteorological data, vibration data, and location data from the monitoring point and upload them to the cloud platform; S4. Establish an atmospheric refractive index model based on the meteorological element data and calculate the atmospheric effect error; calculate the offset error using vibration data; obtain the environmental correction error based on the offset error and the atmospheric effect error. S5. Based on environmental correction error, perform environmental error correction on the original displacement data to obtain corrected ground-based SAR data; compare and verify the corrected ground-based SAR data with the reference benchmark data. The atmospheric refractive index model is as follows: Where e represents humidity, T represents temperature, and P represents temperature. d N represents atmospheric pressure, and N represents the atmospheric refractive index. atmospheric effect error for: in, It is the relative change in atmospheric refractive index between two sampling intervals. It is the distance from the electromagnetic wave emission point to the target point; The specific method for calculating the offset error is as follows: S401. Samples are taken at time intervals equal to the ground-based SAR acquisition period to obtain measured vibration data x. k Where k = 1, 2, 3, ..., n, and n represents the number of samples; S402, Using an m-order polynomial X K Fitting the measured vibration data, we have: X K = a0+a1k+a2k 2 +...+a m k m ,k=1,2,3,...,n ; S403. Select m=3, perform polynomial trend term elimination, and screen polynomial coefficients to ensure that X k With x k The formula for eliminating the linear trend term is obtained by minimizing the sum of squared differences: y=x k -X k =x k -(a0-a1k) ; S404, Calculate the offset error d: in, , These are the phases obtained from two consecutive samples, and λ is the wavelength of the ground-based SAR. The environmental correction error D is: in, This represents the offset error of the i-th sample. This represents the atmospheric effect error of the i-th sampling. This represents the formula for eliminating the linear trend term in the i-th sample, where n represents the number of samples.

2. The method according to claim 1, characterized in that, The meteorological data include wind speed, wind direction, temperature, humidity, air pressure, and rainfall.

3. A ground-based SAR environmental error correction device, characterized in that, The apparatus is used to perform the method according to any one of claims 1-2, the apparatus comprising: Radar reflector, weather station terminal module, tilt vibration sensor, positioning system, 4G communication module, weather sensor, electric displacement stage, bracket, integrated protective box; the device communicates with the cloud platform to transmit or receive data; The radar reflector is mounted on an electrically driven displacement platform, which is located at the lower part of the support to support the radar reflector for high-precision displacement. The radar reflector is used to reflect radar electromagnetic waves and serves as a reference target for ground-based SAR radiation calibration. The meteorological sensor is mounted on the top of the support frame to collect meteorological element data; the meteorological station terminal module is connected to the meteorological sensor to output the meteorological element data to the background for real-time viewing. The positioning system includes a high-precision positioning system receiver and a high-precision positioning system antenna; the high-precision positioning system receiver is used to acquire the device's position data and displacement data; the high-precision positioning system antenna is mounted on the top of the integrated protective box. The integrated protective box is located in the middle of the bracket, and the meteorological station terminal module, 4G communication module and high-precision positioning system receiver are all located inside the integrated protective box; The tilt vibration sensor is mounted on the electric displacement stage to detect vibration data and tilt data of the radar reflector.

4. The apparatus according to claim 3, characterized in that, The device also includes a power module, a storage battery, and a solar power system; The solar power supply system is located on the upper part of the bracket; The power module and the battery are housed inside the integrated protective enclosure; The power supply module provides power to the weather station terminal module, 4G communication module, positioning system, and electric displacement platform. The battery is connected to the power module and the solar power system.

5. The apparatus according to claim 3, characterized in that, The electric displacement stage is controlled by a stepper motor and driven by a ball screw.

6. The apparatus according to claim 3, characterized in that, The device is fixed at the monitoring point during use; The bracket is equipped with a fixing flange at its bottom.

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