Differential interferometric sar satellite deformation rate measurement precision analysis calculation method and system

Abstract

The application provides a differential interferometric SAR satellite deformation rate measurement precision analysis calculation method and system. The implementation steps of the application are as follows: (1) establishing a differential interferometric SAR satellite long-time sequence deformation rate measurement equation, and determining various error sources affecting the system deformation rate measurement precision; (2) deducing an error transfer function of each error source of the differential interferometric SAR long-time sequence deformation rate measurement on the target long-time sequence deformation rate measurement precision; (3) designing satellite system parameters; (4) calculating the influence degree of each error source on the differential interferometric SAR long-time sequence deformation rate measurement precision of the satellite system; and (5) solidifying the calculation process, and quickly responding when the satellite system design parameters change. The application can be used for the overall design of a differential interferometric SAR long-time sequence deformation rate measurement satellite system.

Description

Technical Field

[0001] This invention belongs to the field of signal and information processing technology, specifically, it relates to a method for analyzing and calculating deformation rate measurement, and in particular to a satellite manufacturing method and system for designing differential interferometric SAR satellite system parameters and analyzing the accuracy of long-term deformation rate measurement. Background Technology

[0002] Differential interferometric synthetic aperture radar (DISAR) is an important remote sensing tool for acquiring information on surface deformation, playing a crucial role in monitoring geophysical phenomena such as seismic deformation, landslides, and ground subsidence. In long-term deformation rate measurements using DISAR, SAR satellites repeatedly fly over the same area. Assuming linear surface deformation occurs during these flights, multiple SAR images of the deformation process can be obtained. Under certain conditions of satellite reorbiting time and inter-satellite baseline, interferometric processing of the acquired SAR images yields interferometric phase information. The phase of any pixel in the interferogram represents the sum of the change in distance between the radar and that pixel and the change in the scattering phase of the target. If the scattering phase remains stable during multiple observations, the interferometric phase reflects the change in distance between the target and the radar between two observations, including topographic information, surface deformation, and phase delay caused by atmospheric activity. The topographic phase is determined using known DEM (Digital Elevation) data of the observation area. The phase delay caused by the atmosphere and ionosphere can be calculated by filtering the time-series SAR image and removed from the interferometric phase. The surface deformation rate can then be inverted using the remaining deformation phase.

[0003] The accuracy of long-term deformation rate measurement by differential interferometric SAR (DISAR) satellites is a core indicator of the satellite system, directly impacting the application value of deformation products. Therefore, analyzing the factors influencing the accuracy of long-term deformation rate measurement by DISAR satellites has become a core task in the design of DISAR satellite systems. On one hand, the satellite's overall designer needs to analyze the factors influencing the accuracy of long-term deformation rate measurement by DISAR satellites to identify and allocate various engineering performance requirements. On the other hand, designers also need to perform calculations and analyses on the actual engineering development results of the satellite to evaluate the on-orbit long-term deformation rate measurement performance of the DISAR satellite.

[0004] The analysis of factors affecting the accuracy of long-term deformation rate measurement of differential interferometric SAR satellites involves integrated satellite and ground design, requiring in-depth analysis of the error sensitivity of long-term deformation rate measurement accuracy, and establishment of a full-link error model for long-term deformation rate measurement of differential interferometric SAR satellites.

[0005] Patent document CN109100720B discloses an InSAR surface deformation monitoring method, proposing a high-precision, long-span temporal deformation rate monitoring method under periodic constraints; Patent document CN110673145B discloses an InSAR surface deformation monitoring method and system based on discontinuous coherence, proposing an effective detection technology for regional deformation at points with discontinuous coherence in time; Patent document CN110412574A discloses a distributed target InSAR time-series processing method and device with enhanced spatiotemporal coherence, proposing a spatiotemporal coherence enhancement technology for distributed target InSAR, improving the accuracy of temporal deformation rate measurement; Patent document CN115267779A discloses an InSAR temporal DEM error estimation method, which obtains DEM error through InSAR time-series images; Patent document CN114114258A discloses a transmission tower deformation monitoring method based on SBAS-InSAR technology, proposing a high-precision monitoring technology for transmission tower deformation through temporal short baseline set InSAR.

[0006] The aforementioned patent documents all employ time-series InSAR deformation processing algorithms and applications, but none provide a comprehensive and systematic error analysis or system design for the accuracy of long-term deformation rate measurements based on the system's working principle. With the rapid development of spaceborne differential interferometric SAR technology, the application demand for long-term deformation rate measurement products is increasing. Therefore, it is crucial to conduct in-depth research on how to design a more universal and faster method for analyzing the factors affecting the accuracy of long-term deformation rate measurements for differential interferometric SAR satellites, in order to manufacture satellites accordingly.

[0007] Patent document CN111474544A discloses a landslide deformation monitoring and early warning method based on SAR data, which can reduce monitoring errors caused by factors such as heavy rain, improve the accuracy of InSAR technology in acquiring surface deformation, and provide data and decision support for landslide deformation monitoring and early warning. However, this patent document only describes a differential interferometric SAR data processing method and does not conduct a comprehensive and systematic error analysis on the measurement accuracy of deformation rate over long time series. This invention is the first to analyze the measurement accuracy of differential interferometric SAR satellite deformation rate, and can be applied to the design of differential interferometric SAR satellite systems.

[0008] Patent document CN112034462A discloses a method for improving the accuracy of obtaining surface deformation data using differential interferometric measurement technology. Based on SAR system parameters and satellite orbit parameters, it optimizes differential image pairs and topographic image pairs by comparing the vertical baselines of each image pair, thereby improving the measurement accuracy of surface deformation information. However, this patent document only describes a differential interferometric SAR data processing method and cannot be applied to the accuracy analysis of differential interferometric SAR satellite deformation rate measurements. This invention is the first to analyze the accuracy of differential interferometric SAR satellite deformation rate measurements, and can be applied to the design of differential interferometric SAR satellite systems. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method for analyzing and calculating the deformation rate over a long time series.

[0010] A method for analyzing and calculating the accuracy of differential interferometric SAR satellite deformation rate measurement according to the present invention includes:

[0011] Step S1: Acquire multiple SAR images using differential interferometric SAR, establish the differential interferometric SAR satellite long-term sequence surface deformation rate measurement equation, and determine the error sources affecting the system's positioning accuracy;

[0012] Step S2: Based on the identified error sources affecting the system's positioning accuracy, derive the error transfer function for the long-term deformation rate measurement of the Earth's surface by the differential interferometric SAR satellite;

[0013] Step S3: Set the satellite system parameters according to the requirements for long-term series deformation rate measurement;

[0014] Step S4: Based on the set satellite system parameters and error sources, calculate the degree of influence of the error sources on the accuracy of differential interferometric SAR long-term series deformation rate measurement of the Earth's surface using the error transfer function.

[0015] Preferably, step S1 includes:

[0016] Step S1.1: Perform interferometric processing on multiple SAR images of the same area acquired at different times;

[0017] Step S1.2: After removing the ground elevation phase using prior information, analyze the long-term deformation rate of the differential interferometric SAR surface in the obtained observation area;

[0018] Step S1.3: Based on multiple SAR images of the same area acquired at different times, assuming a total of M SAR images, the observation equation for the long-term deformation rate measurement of the differential interferometric SAR surface is:

[0019]

[0020] In the formula, φ k Let Δt be the interferometric phase of the k-th interferometric SAR phase image, v be the surface deformation rate, and the subscript k represent the k-th interferometric SAR phase image. k To obtain the time difference between the primary and secondary SAR images corresponding to the k-th interferometric SAR phase image, H amb,k Let φ be the ambiguity height of the k-th interferometric SAR phase image, Δh be the residual elevation error, and φ be the fuzzy height. bsl,k Let φ be the phase caused by the baseline measurement error of the k-th interferometric SAR phase map. atm,k For the differential atmospheric delay phase of the k-th interferometric SAR phase map during transit, φ cor,k λ represents the decoherent noise phase of the kth interferometric SAR phase image, where λ is the radar wavelength.

[0021]

[0022] In the formula,

[0023]

[0024] b = [φ1 φ2 … φ M-1 ] T

[0025] M is the number of SAR images;

[0026] Based on the observation equation for long-term surface deformation rate measurement by differential interferometric SAR, the main error sources affecting the accuracy of differential interferometric SAR surface deformation rate measurement are decoherence phase error, phase error caused by baseline residual, and atmospheric phase error.

[0027] Preferably, in step S2:

[0028] The transfer function of interferometric phase error on the accuracy of surface deformation rate inversion is:

[0029]

[0030] in, To determine the accuracy of the surface deformation rate inversion, E{·} represents the expected value, and the subscript 1,1 indicates the element in the first row and first column of the matrix;

[0031] The transfer function of the decoherent phase error on the accuracy of surface deformation rate inversion is:

[0032]

[0033] in,

[0034]

[0035] Nl Let γ be the number of views and γ be the coherence coefficient. The coherence coefficient can be expressed as:

[0036] γ=γ temp ·γ SNR ·γ amb ·γ ISLR ·γ B ·γ Doppler ·γ vol ·γ coregis ·γ jam

[0037] In the formula, γ temp For time-decoherence, γ SNR For signal-to-noise ratio decoherence, γ amb To fuzzy decorrelation, γ ISLR For sidelobe decoherence, γ B For baseline decoherence, γ Doppler For Doppler decoherence, γ vol For volume scattering decoherence, γ coregis To register and decoherentize, γ jam To decoherentize the interference;

[0038]

[0039] in, The coherence coefficient of the useful signal in the primary and secondary SAR images, γ j The coherence coefficient of primary and secondary SAR image interference, SJR i Let i be the signal-to-interference ratio of the i-th image. The original signal interference phase, φ j The interference phase between the interference signals;

[0040] The phase φ caused by the baseline measurement error of the k-th interferometric SAR phase map bsl,k A low-pass filter is used to correct the phase error of the interferometric baseline;

[0041] For the atmospheric phase error φ of the differential atmospheric phase during transit in the k-th interferometric SAR phase map. atm,k Spatial high-pass filter and time low-pass filter are used to suppress it.

[0042] Preferably, in step S3, the satellite is manufactured by setting parameters according to the requirements for long-term satellite deformation rate measurement; the satellite parameters include: satellite orbital altitude, pipeline control radius, orbital return period, radar carrier frequency, and operating wavelet parameters.

[0043] Preferably, it further includes:

[0044] Step S5: Solidify the calculation process for long-term deformation rate measurement accuracy to respond to changes in satellite system parameters.

[0045] A differential interferometric SAR satellite deformation rate measurement accuracy analysis and calculation system provided by the present invention includes:

[0046] Module M1: Acquire multiple SAR images through differential interferometric SAR, establish the measurement equation for the surface deformation rate of differential interferometric SAR satellite over a long time series, and determine the error sources affecting the system's positioning accuracy;

[0047] Module M2: Based on the identified error sources affecting the system's positioning accuracy, derive the error transfer function for long-term surface deformation rate measurements by differential interferometric SAR satellites;

[0048] Module M3: Sets satellite system parameters according to the requirements of long-term deformation rate measurement;

[0049] Module M4: Based on the set satellite system parameters and error sources, calculates the error transfer function of the differential interferometric SAR satellite long-term series deformation rate measurement and calculates the degree of influence of the error sources on the accuracy of the differential interferometric SAR long-term series deformation rate measurement.

[0050] Preferably, the module M1 includes:

[0051] Module M1.1: Performs interferometric processing on multiple SAR images of the same area acquired at different times;

[0052] Module M1.2: After removing the ground elevation phase using prior information, analyze the long-term deformation rate of the differential interferometric SAR surface in the obtained observation area;

[0053] Module M1.3: Based on multiple SAR images of the same area acquired at different times, assuming a total of M SAR images, the observation equation for measuring the long-term deformation rate of the surface using differential interferometric SAR is:

[0054]

[0055] In the formula, φ k Let Δt be the interferometric phase of the k-th interferometric SAR phase image, v be the surface deformation rate, and the subscript k represent the k-th interferometric SAR phase image. k To obtain the time difference between the primary and secondary SAR images corresponding to the k-th interferometric SAR phase image, H amb,k Let φ be the ambiguity height of the k-th interferometric SAR phase image, Δh be the residual elevation error, and φ be the fuzzy height. bsl,k Let φ be the phase caused by the baseline measurement error of the k-th interferometric SAR phase map. atm,kFor the differential atmospheric delay phase of the k-th interferometric SAR phase map during transit, φ cor,k λ represents the decoherent noise phase of the kth interferometric SAR phase image, where λ is the radar wavelength.

[0056]

[0057] In the formula,

[0058]

[0059] b = [φ1 φ2 … φ M-1 ] T

[0060] M is the number of SAR images;

[0061] Based on the observation equation for long-term surface deformation rate measurement by differential interferometric SAR, the main error sources affecting the accuracy of differential interferometric SAR surface deformation rate measurement are decoherence phase error, phase error caused by baseline residual, and atmospheric phase error.

[0062] Preferably, in module M2:

[0063] The transfer function of interferometric phase error on the accuracy of surface deformation rate inversion is:

[0064]

[0065] in, To determine the accuracy of the surface deformation rate inversion, E{·} represents the expected value, and the subscript 1,1 indicates the element in the first row and first column of the matrix;

[0066] The transfer function of the decoherent phase error on the accuracy of surface deformation rate inversion is:

[0067]

[0068] in,

[0069]

[0070] N l Let γ be the number of views and γ be the coherence coefficient. The coherence coefficient can be expressed as:

[0071] γ=γ temp ·γ SNR ·γ amb ·γ ISLR ·γ B ·γ Doppler ·γ vol ·γ coregis ·γ jam

[0072] In the formula, γ temp For time-decoherence, γ SNR For signal-to-noise ratio decoherence, γ amb To fuzzy decorrelation, γ ISLR For sidelobe decoherence, γ B For baseline decoherence, γ Doppler For Doppler decoherence, γ vol For volume scattering decoherence, γ coregis To register and decoherentize, γ jam To decoherentize the interference;

[0073]

[0074] in, The coherence coefficient of the useful signal in the primary and secondary SAR images, γ j The coherence coefficient of primary and secondary SAR image interference, SJR i Let i be the signal-to-interference ratio of the i-th image. The original signal interference phase, φ j The interference phase between the interference signals;

[0075] The phase φ caused by the baseline measurement error of the k-th interferometric SAR phase map bsl,k A low-pass filter is used to correct the phase error of the interferometric baseline;

[0076] For the atmospheric phase error φ of the differential atmospheric phase during transit in the k-th interferometric SAR phase map. atm,k Spatial high-pass filter and time low-pass filter are used to suppress it.

[0077] Preferably, in module M3, the satellite is manufactured by setting parameters according to the requirements for long-term satellite deformation rate measurement; the satellite parameters include: satellite orbital altitude, pipeline control radius, orbital return period, radar carrier frequency, and operating wavelet parameters.

[0078] Preferably, it further includes:

[0079] Module M5: Solidifies the process for calculating the accuracy of long-term deformation rate measurements, responding to changes in satellite system parameters.

[0080] Compared with the prior art, the present invention has the following beneficial effects:

[0081] 1. This invention can be used in the overall design of a satellite system for measuring the deformation rate of a long-term differential interferometric SAR sequence, and solves the problem of changes in the measurement accuracy of the deformation rate of a long-term differential interferometric SAR sequence caused by changes in the satellite system design parameters.

[0082] 2. This invention can respond faster when satellite design parameters change, and at the same time quickly provide feedback on the impact on the accuracy of long-term deformation rate measurement of differential interferometric SAR.

[0083] 3. The processing approach of this invention differs from existing design methods and can solve the problem of analyzing the factors affecting the accuracy of differential interferometric SAR long-term sequence deformation rate measurement in complex electromagnetic environments (with external interference).

[0084] 4. This invention is based on a rigorous theoretical model for calculation and has solidified the calculation process. Compared with existing technologies, the error items are more comprehensively sorted out. Attached Figure Description

[0085] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0086] Figure 1 A schematic diagram of the processing steps in the method for analyzing the factors affecting the accuracy of long-term deformation rate measurements using differential interferometric SAR.

[0087] Figure 2 A geometrical schematic diagram of long-term differential interferometric SAR observations of surface deformation rate;

[0088] Figure 3 The curve showing the variation of the accuracy of deformation rate measurement over a long time series with the coherence coefficient;

[0089] Figure 4 The curve showing the variation of the accuracy of long-term deformation rate measurement with atmospheric delay phase error;

[0090] Figure 5 The curve shows the change in the accuracy of deformation rate measurement over a long time series as a function of the baseline residual.

[0091] Figure 2 In the middle, P t Indicates the target location; P s (t N ) represents t s The position of the satellite at any given time, r1 represents the slant range of the main image radar. Detailed Implementation

[0092] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0093] This invention proposes a method for analyzing factors affecting the accuracy of long-term deformation rate measurements of differential interferometric SAR satellites, and manufactures satellites based on the analysis conclusions. The implementation steps are as follows: Figure 1 As shown, it specifically includes:

[0094] Step 1: Acquire multiple SAR images using differential interferometric SAR. These images will reflect the parameters required for the calculation formula of this invention. Establish the long-term sequence surface deformation rate measurement equation of differential interferometric SAR satellites and identify the error sources affecting the system's positioning accuracy.

[0095] Step 2: Based on the identified error sources affecting the system's positioning accuracy, derive the error transfer function for the long-term deformation rate measurement of the Earth's surface by the differential interferometric SAR satellite.

[0096] Step 3: Design satellite system parameters based on the requirements for long-term deformation rate measurement.

[0097] Step 4: Based on the set satellite system parameters and error sources, calculate the degree of influence of the error sources on the accuracy of differential interferometric SAR long-term series deformation rate measurement of the Earth's surface using the error transfer function.

[0098] Step 5: Solidify the calculation process for long-term deformation rate measurement accuracy, so that it can respond quickly to changes in satellite system parameters.

[0099] Specifically, step 1 includes the following sub-steps:

[0100] Step 1.1: Perform interferometric processing on multiple SAR images of the same area acquired over a relatively long period of time at different times, such as... Figure 2 As shown. Ideally, more than 25 SAR images should be interferometrically processed.

[0101] Step 1.2: After removing the ground elevation phase using prior information, analyze the long-term deformation rate of the differential interferometric SAR surface in the obtained observation area.

[0102] Step 1.3: Based on multiple SAR images of the same area at different times over a relatively long period of time, assuming there are a total of M SAR images, the observation equation for measuring the long-term deformation rate of the surface using differential interferometric SAR is:

[0103]

[0104] In the formula, φ k Let Δt be the interferometric phase of the k-th interferometric SAR phase image, v be the surface deformation rate, and the subscript k represent the k-th interferometric SAR phase image. k To obtain the time difference between the primary and secondary SAR images corresponding to the k-th interferometric SAR phase image, Hamb,k Let φ be the ambiguity height of the k-th interferometric SAR phase image, Δh be the residual elevation error, and φ be the fuzzy height. bsl,k Let φ be the phase caused by the baseline measurement error of the k-th interferometric SAR phase map. atm,k For the differential atmospheric delay phase of the k-th interferometric SAR phase map during transit, φ cor,k Let λ be the decoherent noise phase of the k-th interferometric SAR phase map, and λ be the radar wavelength.

[0105]

[0106] In the formula,

[0107]

[0108] b = [φ1 φ2 … φ M-1 ] T

[0109] M represents the number of SAR images.

[0110] According to the observation equation for long-term surface deformation rate measurement by differential interferometric SAR, the main error sources affecting the accuracy of differential interferometric SAR surface deformation rate measurement are decoherence phase error, phase error caused by baseline residual, and atmospheric phase error.

[0111] Step 2:

[0112] First, the transfer function of interferometric phase error on the accuracy of surface deformation rate inversion is:

[0113]

[0114] in, E{·} represents the expected value, and the subscript 1,1 indicates the element in the first row and first column of the matrix.

[0115] The transfer function of the decoherent phase error on the accuracy of surface deformation rate inversion is:

[0116]

[0117] in,

[0118]

[0119] N l Let γ be the number of views and γ be the coherence coefficient. The coherence coefficient can be expressed as:

[0120] γ=γ temp ·γ SNR ·γ amb ·γ ISLR ·γB ·γ Doppler ·γ vol ·γ coregis ·γ jam

[0121] In the formula, γ temp For time-decoherence, γ SNR For signal-to-noise ratio decoherence, γ amb To fuzzy decorrelation, γ ISLR For sidelobe decoherence, γ B For baseline decoherence, γ Doppler For Doppler decoherence, γ vol For volume scattering decoherence, γ coregis To register and decoherentize, γ jam To decoherentize the interference.

[0122]

[0123] in, The coherence coefficient of the useful signal in the primary and secondary SAR images, γ j The coherence coefficient of primary and secondary SAR image interference, SJR i Let i be the signal-to-interference ratio of the i-th image. The original signal interference phase, φ j The interference phase is the phase between the interference signals.

[0124] The phase φ caused by the baseline measurement error of the k-th interferometric SAR phase map bsl,k This error will cause spatially varying (approximately linear) deformation measurement errors in the interferometric phase image after terrain removal, and the interferometric baseline error between each interferometric phase image is random. Since the phase error caused by the interferometric baseline error has spatially varying characteristics, a low-pass filter is used to correct the interferometric baseline phase error, such as estimating the linearly varying component along the range direction in the interferometric phase image after terrain removal.

[0125] For the atmospheric phase error φ of the differential atmospheric phase during transit in the k-th interferometric SAR phase map. atm,k It has spatially slowly varying and temporally rapidly varying properties, which can be suppressed by using spatial high-pass filters and temporal low-pass filters.

[0126] Step 3 specifically includes the following:

[0127] Based on the requirements for long-term satellite deformation rate measurement, the satellite parameters are set, and the satellite is manufactured. These satellite parameters include: satellite orbital altitude, pipeline control radius, orbital return period, radar carrier frequency, and operating wavefront parameters.

[0128] The following table shows an example of the preliminary design results for satellite system parameters:

[0129] parameter Value orbital altitude 607km Pipeline control radius 350m orbital regression cycle 8 days radar carrier frequency 1.26GHz Radar slant range 700km

[0130] Step 4 specifically includes the following:

[0131] The influence of coherence coefficient on the accuracy of deformation rate measurement of long-term differential interferometric SAR is as follows: Figure 3 As shown in the figure, the accuracy of long-term deformation rate measurement increases with the increase of the coherence coefficient. To ensure the accuracy of long-term deformation rate measurement, a coherence coefficient better than 0.7 is usually required, corresponding to a long-term surface deformation rate measurement accuracy of approximately 1.86 mm / year.

[0132] The impact of atmospheric delay phase error on the accuracy of long-term deformation rate measurement in differential interferometric SAR is as follows: Figure 4 As shown in the figure, the accuracy of long-term deformation rate measurement decreases with increasing atmospheric delay phase error.

[0133] The impact of baseline residuals on the accuracy of long-term deformation rate measurements in differential interferometric SAR is as follows: Figure 5 As shown in the figure, the accuracy of deformation rate measurement over long time series decreases as the baseline residual increases.

[0134] Step 5: Solidify the calculation process for long-term deformation rate measurement accuracy, so that it can respond quickly to changes in satellite system parameters.

[0135] This invention also provides a system for analyzing and calculating the accuracy of differential interferometric SAR satellite deformation rate measurements. Those skilled in the art can implement this system by executing the steps of the method for analyzing and calculating the accuracy of differential interferometric SAR satellite deformation rate measurements. In other words, those skilled in the art can understand the method for analyzing and calculating the accuracy of differential interferometric SAR satellite deformation rate measurements as a specific implementation of the system for analyzing and calculating the accuracy of differential interferometric SAR satellite deformation rate measurements. Specifically, the system for analyzing and calculating the accuracy of differential interferometric SAR satellite deformation rate measurements includes:

[0136] Module M1: Acquire multiple SAR images through differential interferometric SAR, establish the measurement equation for the surface deformation rate of differential interferometric SAR satellite over a long time series, and determine the error sources affecting the system's positioning accuracy;

[0137] Module M2: Based on the identified error sources affecting the system's positioning accuracy, derive the error transfer function for long-term surface deformation rate measurements by differential interferometric SAR satellites;

[0138] Module M3: Sets satellite system parameters according to the requirements of long-term deformation rate measurement;

[0139] Module M4: Based on the set satellite system parameters and error sources, calculates the error transfer function of the differential interferometric SAR satellite long-term series deformation rate measurement and calculates the degree of influence of the error sources on the accuracy of the differential interferometric SAR long-term series deformation rate measurement.

[0140] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for analyzing and calculating the accuracy of differential interferometric SAR satellite deformation rate measurement, characterized in that, include: Step S1: Acquire multiple SAR images using differential interferometric SAR, establish the differential interferometric SAR satellite long-term sequence surface deformation rate measurement equation, and determine the error sources affecting the system's positioning accuracy; Step S2: Based on the identified error sources affecting the system's positioning accuracy, derive the error transfer function for the long-term deformation rate measurement of the Earth's surface by the differential interferometric SAR satellite; Step S3: Set the satellite system parameters according to the requirements for long-term series deformation rate measurement; Step S4: Based on the set satellite system parameters and error sources, calculate the degree of influence of the error sources on the accuracy of differential interferometric SAR long-term series deformation rate measurement of the Earth's surface using the error transfer function. In step S2: The transfer function of interferometric phase error on the accuracy of surface deformation rate inversion is: in, To determine the accuracy of the surface deformation rate inversion, E{·} represents the expected value, and the subscript 1,1 indicates the element in the first row and first column of the matrix; The transfer function of the decoherent phase error on the accuracy of surface deformation rate inversion is: in, N l For multiple views, γ is the coherence coefficient, which can be expressed as: c = c temp ·c SNR ·c amb ·c ISLR ·c B ·c Doppler ·c vol ·c coregis ·c jam In the formula, γ temp For time-decoherence, γ SNR For signal-to-noise ratio decoherence, γ amb To fuzzy decorrelation, γ ISLR For sidelobe decoherence, γ B For baseline decoherence, γ Doppler For Doppler decoherence, γ vol For volume scattering decoherence, γ coregis To register and decoherentize, γ jam To decoherentize the interference; in, The coherence coefficient of the useful signal in the primary and secondary SAR images, γ j The coherence coefficient of primary and secondary SAR image interference, SJR i Let i be the signal-to-interference ratio of the i-th image. The original signal interference phase, φ j The interference phase between the interference signals; The phase φ caused by the baseline measurement error of the k-th interferometric SAR phase map bsl,k A low-pass filter is used to correct the phase error of the interference baseline; For the atmospheric phase error φ of the differential atmospheric phase during transit in the k-th interferometric SAR phase map. atm,k Spatial high-pass filter and time low-pass filter are used to suppress it.

2. The method for analyzing and calculating the accuracy of differential interferometric SAR satellite deformation rate measurement according to claim 1, characterized in that, Step S1 includes: Step S1.1: Perform interferometric processing on multiple SAR images of the same area acquired at different times; Step S1.2: After removing the ground elevation phase using prior information, analyze the long-term deformation rate of the differential interferometric SAR surface in the obtained observation area; Step S1.3: Based on multiple SAR images of the same area acquired at different times, assuming a total of M SAR images, the observation equation for the long-term deformation rate measurement of the differential interferometric SAR surface is: In the formula, φ k Let Δt be the interferometric phase of the k-th interferometric SAR phase image, v be the surface deformation rate, and the subscript k represent the k-th interferometric SAR phase image. k To obtain the time difference between the primary and secondary SAR images corresponding to the k-th interferometric SAR phase image, H amb,k Let φ be the ambiguity height of the k-th interferometric SAR phase image, Δh be the residual elevation error, and φ be the fuzzy height. bsl,k Let φ be the phase caused by the baseline measurement error of the k-th interferometric SAR phase map. atm,k For the differential atmospheric delay phase of the k-th interferometric SAR phase map during transit, φ cor,k λ represents the decoherent noise phase of the kth interferometric SAR phase image, where λ is the radar wavelength. In the formula, b=[φ1 φ2 … φ M-1 ] T M is the number of SAR images; Based on the observation equation for long-term surface deformation rate measurement by differential interferometric SAR, the error sources affecting the accuracy of differential interferometric SAR surface deformation rate measurement are identified as decoherence phase error, phase error caused by baseline residual, and atmospheric phase error.

3. The method for analyzing and calculating the accuracy of differential interferometric SAR satellite deformation rate measurement according to claim 1, characterized in that, In step S3, the satellite is manufactured by setting parameters according to the requirements for long-term satellite deformation rate measurement; the satellite parameters include: satellite orbital altitude, pipeline control radius, orbital return period, radar carrier frequency, and operating wavelet parameters.

4. The method for analyzing and calculating the accuracy of differential interferometric SAR satellite deformation rate measurement according to claim 1, characterized in that, Also includes: Step S5: Solidify the calculation process for long-term deformation rate measurement accuracy to respond to changes in satellite system parameters.

5. A system for analyzing and calculating the accuracy of differential interferometric SAR satellite deformation rate measurement, characterized in that, include: Module M1: Acquire multiple SAR images through differential interferometric SAR, establish the measurement equation for the surface deformation rate of differential interferometric SAR satellite over a long time series, and determine the error sources affecting the system's positioning accuracy; Module M2: Based on the identified error sources affecting the system's positioning accuracy, derive the error transfer function for long-term surface deformation rate measurements by differential interferometric SAR satellites; Module M3: Sets satellite system parameters according to the requirements of long-term deformation rate measurement; Module M4: Based on the set satellite system parameters and error sources, calculate the error transfer function of the differential interferometric SAR satellite long-term series deformation rate measurement, and calculate the degree of influence of the error sources on the accuracy of the differential interferometric SAR long-term series deformation rate measurement; In module M2: The transfer function of interferometric phase error on the accuracy of surface deformation rate inversion is: in, To determine the accuracy of the surface deformation rate inversion, E{·} represents the expected value, and the subscript 1,1 indicates the element in the first row and first column of the matrix; The transfer function of the decoherent phase error on the accuracy of surface deformation rate inversion is: in, N l For multiple views, γ is the coherence coefficient, which can be expressed as: c = c temp ·c SNR ·c amb ·c ISLR ·c B ·c Doppler ·c vol ·c coregis ·c jam In the formula, γ temp For time-decoherence, γ SNR For signal-to-noise ratio decoherence, γ amb To fuzzy decorrelation, γ ISLR For sidelobe decoherence, γ B For baseline decoherence, γ Doppler For Doppler decoherence, γ vol For volume scattering decoherence, γ coregis To register and decoherentize, γ jam To decoherentize the interference; in, The coherence coefficient of the useful signal in the primary and secondary SAR images, γ j The coherence coefficient of primary and secondary SAR image interference, SJR i Let i be the signal-to-interference ratio of the i-th image. The original signal interference phase, φ j The interference phase between the interference signals; The phase φ caused by the baseline measurement error of the k-th interferometric SAR phase map bsl,k A low-pass filter is used to correct the phase error of the interference baseline; For the atmospheric phase error φ of the differential atmospheric phase during transit in the k-th interferometric SAR phase map. atm,k Spatial high-pass filter and time low-pass filter are used to suppress it.

6. The differential interferometric SAR satellite deformation rate measurement accuracy analysis and calculation system according to claim 5, characterized in that, The module M1 includes: Module M1.1: Performs interferometric processing on multiple SAR images of the same area acquired at different times; Module M1.2: After removing the ground elevation phase using prior information, analyze the long-term deformation rate of the differential interferometric SAR surface in the obtained observation area; Module M1.3: Based on multiple SAR images of the same area acquired at different times, assuming a total of M SAR images, the observation equation for measuring the long-term deformation rate of the surface using differential interferometric SAR is: In the formula, φ k Let Δt be the interferometric phase of the k-th interferometric SAR phase image, v be the surface deformation rate, and the subscript k represent the k-th interferometric SAR phase image. k To obtain the time difference between the primary and secondary SAR images corresponding to the k-th interferometric SAR phase image, H amb,k Let φ be the ambiguity height of the k-th interferometric SAR phase image, Δh be the residual elevation error, and φ be the fuzzy height. bsl,k Let φ be the phase caused by the baseline measurement error of the k-th interferometric SAR phase map. atm,k For the differential atmospheric delay phase of the k-th interferometric SAR phase map during transit, φ cor,k λ represents the decoherent noise phase of the kth interferometric SAR phase image, where λ is the radar wavelength. In the formula, b=[φ1 φ2 … φ M-1 ] T M is the number of SAR images; Based on the observation equation for long-term surface deformation rate measurement by differential interferometric SAR, the error sources affecting the accuracy of differential interferometric SAR surface deformation rate measurement are identified as decoherence phase error, phase error caused by baseline residual, and atmospheric phase error.

7. The differential interferometric SAR satellite deformation rate measurement accuracy analysis and calculation system according to claim 5, characterized in that, In module M3, the satellite is manufactured by setting parameters according to the requirements for long-term satellite deformation rate measurement. The satellite parameters include: satellite orbital altitude, pipeline control radius, orbital return period, radar carrier frequency, and operating wavelet parameters.

8. The differential interferometric SAR satellite deformation rate measurement accuracy analysis and calculation system according to claim 5, characterized in that, Also includes: Module M5: Solidifies the process for calculating the accuracy of long-term deformation rate measurements, responding to changes in satellite system parameters.

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