Method, device and equipment for remotely sensing and monitoring sag of power transmission conductor and medium

Abstract

The invention relates to the technical field of remote sensing monitoring of power transmission lines, in particular to a method, a device, equipment and a medium for remote sensing monitoring of sag of a power transmission conductor, and the method comprises the steps: obtaining the positioning deviation of a synthetic aperture radar image for correcting the geometric positioning error of imaging of the power transmission conductor; determining radar coordinate system coordinates of mounting points at two ends of the power transmission conductor and projection points of the mounting points on a given ellipsoid reference surface, and extracting radar coordinate system coordinates of a scattering spot center point of the power transmission conductor; and calculating the sag state of the power transmission conductor at the image shooting moment according to the mounting points at the two ends of the power transmission conductor, the projection points on the given ellipsoid reference surface and the central point of the scattering spot of the power transmission conductor. Therefore, the problem of how to accurately extract the three-dimensional state of the sag of the power transmission conductor by using the scattering spot imaging characteristics of the power transmission conductor is solved. The method can be embedded into a data center or a remote sensing sensor platform through electronic equipment such as a computer, and real-time monitoring, evaluation and early warning of the sag of the transmission conductor are achieved.

Description

Technical Field

[0001] The present application relates to the technical field of remote sensing monitoring of overhead power transmission lines, and in particular to a method, device, equipment and medium for remote sensing monitoring of transmission line sag. Background Art

[0002] As the scale of modern power systems continues to expand, the length and complexity of transmission lines are also increasing. SAR (Synthetic Aperture Radar) is an active microwave sensor that works continuously all day and all night. It can work continuously in all weather conditions and is not affected by sunlight. Using SAR remote sensing imaging detection technology, the sag state of transmission conductors / ground wires can be monitored in real time under harsh climate environments. It can identify abnormal sag of transmission lines and broken transmission conductors / ground wires caused by factors such as icing, dancing, and hardware damage. This technology is expected to improve the reliability and robustness of the safe operation and maintenance of overhead transmission lines.

[0003] The current SAR remote sensing technology mainly uses interferometric SAR technology to monitor the deformation of the surface where the transmission tower is located, and identifies the characteristic targets of geological environmental disasters around the transmission tower by combining SAR image time series analysis methods and deep learning technologies. However, the imaging characteristics of the transmission conductor of the overhead transmission line in the SAR image are ignored. In theory, the sag state of the transmission conductor / ground wire target can be extracted. The periodic changes in the scattered spot texture characteristics of the transmission conductor in the time series SAR image reflect the changes in the sag state of the transmission conductor, but there is a lack of quantitative evaluation theory and methods, and it is impossible to quantitatively analyze the imaging characteristics of the transmission conductor in the SAR image, and it is also difficult to extract the three-dimensional state information of the transmission conductor / ground wire from the two-dimensional SAR image. Summary of the invention

[0004] The present application provides a method, device, equipment and medium for remote sensing monitoring of transmission line sag, so as to solve the problem of how to effectively utilize the imaging characteristics of the transmission conductor / ground wire scattering spots in the synthetic aperture radar image to accurately extract the transmission conductor / ground wire sag change information. Considering that the scattering characteristics of the transmission conductor and the transmission ground wire in the radar image have good consistency, the present application takes the transmission conductor as an example to carry out the discussion of the relevant technical method, and the technical method is also suitable for the monitoring information extraction of the ground wire sag of the overhead transmission line.

[0005] The first aspect of the present application provides a method for remote sensing monitoring of transmission line sag, comprising the following steps: obtaining the positioning deviation of a synthetic aperture radar image to correct the geometric positioning error of transmission line imaging; determining the radar coordinate system coordinates of the mounting points at both ends of the transmission line and their projection points on a given ellipsoid reference surface, and extracting the radar coordinate system coordinates of the center point of the transmission line scattering spot; calculating the sag state of the transmission line at the time of image shooting based on the mounting points at both ends of the transmission line and their projection points on a given ellipsoid reference surface and the center point of the transmission line scattering spot.

[0006] Optionally, determining the positioning deviation of the synthetic aperture radar image according to the ground control point includes: obtaining the geographical coordinates actually measured by the ground control point; calculating the geometric positioning coordinates of the geographical coordinates actually measured by the ground control point in the radar coordinate system using the geographical coordinates and the range Doppler equation; determining the positioning deviation value of the synthetic aperture radar image based on the radar scattering imaging center point coordinates and the geometric positioning coordinates of the ground control point, wherein the radar scattering imaging center point coordinates of the ground control point are the coordinates of the scattering intensity extreme point within a preset range of the ground control point target, and the positioning deviation value of the radar image is used to correct the geometric positioning of the synthetic aperture radar image.

[0007] Optionally, the radar coordinate system coordinates of the mounting points at both ends of the transmission line and their projection points on a given reference ellipsoid are determined according to the corrected geometric positioning parameters, including: acquiring imaging parameters of a synthetic aperture radar image; determining the coordinates of the mounting points at both ends of the transmission line according to the imaging parameters, positioning deviations and a range Doppler model; defining an ellipsoidal datum of a given elevation, wherein the given elevation is lower than the lowest point of suspension of the transmission line, and determining the geographic coordinates of corresponding points of the mounting points at both ends of the transmission line vertically projected onto the ellipsoidal datum of the given elevation; determining the radar coordinate system coordinates of the mounting points at both ends of the transmission line and corresponding points of the mounting points at both ends projected onto the ellipsoidal datum of the given elevation according to the imaging parameters, positioning deviations and a range Doppler model.

[0008] Optionally, according to the radar coordinate system coordinates of the mounting points at both ends of the transmission line and their projection points on a given reference ellipsoid, and the coordinates of the center point of the scattering spot of the transmission line, an expression of the transmission line and an elevation function in the radar coordinate system are constructed, and the sag state of the transmission line at the time of synthetic aperture radar image shooting is calculated, including: obtaining the expression of the transmission line at the time of synthetic aperture radar image shooting according to the coordinates of the center point of the scattering spot of the transmission line and the radar coordinate system coordinates of the hanging points at both ends of the transmission line; constructing a straight line equation according to the radar coordinate system coordinates of the projection points of the mounting points at both ends of the transmission line on the ellipsoid reference surface of a given elevation, and obtaining the elevation function of the transmission line in combination with the transmission line expression; according to the transmission line expression obtained at the time of radar image shooting and the calculated elevation function of the transmission line, the sag function of the transmission line at the time of radar image shooting in three-dimensional space is determined by the range Doppler equation.

[0009] Optionally, in the plane of the radar coordinate system, the transmission line expression of the transmission line at the time of synthetic aperture radar image shooting is obtained according to the coordinates of the center point of the scattering spot of the transmission line and the radar coordinate system coordinates of the hanging points at both ends of the transmission line, including: obtaining the coordinates of the center point of the scattering spot of the transmission line as the coordinates of the extreme point of the scattering intensity within a preset range of the scattering spot; using the radar coordinate system coordinates of the center point of the scattering spot of the transmission line and the mounting points at both ends of the line, under the condition that the tangent equation of the sag state function at the center point of the scattering spot is zero or there is an extreme value in the distance direction, the transmission line expression of the transmission line in the radar coordinate system is obtained, and the transmission line expression is a parabolic equation or a hyperbolic equation.

[0010] Optionally, a straight line equation is constructed according to the radar coordinate system coordinates of the projection points of the mounting points at both ends of the transmission line on the ellipsoid datum plane of a given elevation, and the elevation function of the transmission line is obtained in combination with the transmission line expression, including: obtaining the geographic coordinates of the projection points of the mounting points at both ends of the transmission line on the ellipsoid datum plane of a given elevation, and obtaining the coordinates of the two projection points in the radar coordinate system through the range Doppler equation, and constructing the straight line equation connecting the two projection points; solving the range deviation function between the straight line equation of the two projection points and the transmission line expression point by point along the azimuth direction, and obtaining the incident angle and range resolution parameters of the synthetic aperture radar image; and determining the elevation function of the transmission line based on the range deviation function, the incident angle and the range resolution parameters.

[0011] Optionally, the sag state of the transmission line at the time of synthetic aperture radar image shooting is calculated according to the transmission line expression and the elevation function, including: solving the three-dimensional space sag state of the transmission line in the geographic coordinate system according to the transmission line expression, the elevation function, the range Doppler equation and the ellipsoid equation; obtaining the sag state of the transmission line in the local rectangular coordinate system based on the three-dimensional space sag state of the transmission line in the geographic coordinate system and the local rectangular coordinate system conversion parameters, and calculating its maximum sag value and minimum sag value.

[0012] The second aspect of the present application provides a device for remote sensing monitoring of transmission line sag, including: a determination module, used to determine the positioning deviation of a synthetic aperture radar image according to a ground control point; a correction module, used to correct the geometric positioning error of the synthetic aperture radar image according to the positioning deviation, determine the radar coordinate system coordinates of the mounting points at both ends of the transmission line and their projection points on a given reference ellipsoid according to the corrected geometric positioning error, and extract the coordinates of the center point of the transmission line scattering spot; a calculation module, used to construct a transmission line expression and an elevation function in the radar coordinate system based on the radar coordinates of the mounting points at both ends of the transmission line and their projection points on a given reference ellipsoid and the coordinates of the center point of the transmission line scattering spot, and calculate the sag state of the transmission line at the time of synthetic aperture radar image shooting according to the transmission line expression and the elevation function.

[0013] Optionally, the determination module is further used to obtain the actual measured geographic coordinates of the ground control point in the synthetic aperture radar image; use the geographic coordinates and the range Doppler equation to calculate the geometric positioning coordinates of the actual measured geographic coordinates of the ground control point in the radar coordinate system; determine the positioning deviation value of the synthetic aperture radar image based on the radar scattering imaging center point coordinates and the geometric positioning coordinates of the ground control point, wherein the radar scattering imaging center point coordinates of the ground control point are the coordinates of the scattering intensity extreme point within a preset range of the ground control point target, and the positioning deviation value of the radar image is used to correct the geometric positioning of the synthetic aperture radar image.

[0014] Optionally, the correction module is further used to correct the geometric positioning error of the synthetic aperture radar image according to the positioning deviation, solve the corresponding radar coordinate system coordinates through the range Doppler equation according to the geographical coordinates of the mounting points at both ends of the transmission line and the geographical coordinates of the projection points on a given reference ellipsoid, and extract the coordinates of the center point of the scattering spot of the transmission line.

[0015] Optionally, the calculation module is further used to construct an expression and elevation function of the transmission line in the radar coordinate system according to the radar coordinate system coordinates of the mounting points at both ends of the transmission line and their projection points on a given reference ellipsoid, and the coordinates of the center point of the scattering spot of the transmission line, and calculate the set of geographic coordinate points of the sag state of the transmission line at the time of synthetic aperture radar image shooting using the range Doppler equation based on the transmission line expression and the elevation function.

[0016] Optionally, the calculation module is further used to obtain the coordinates of the center point of the scattering spot of the transmission line as the coordinates of the extreme point of the scattering intensity within a preset range of the scattering spot; using the radar coordinate system coordinates of the center point of the scattering spot of the transmission line and the mounting points at both ends of the line, and under the condition that the tangent equation of the sag state function at the center point of the scattering spot is zero or there is an extreme value in the distance direction, the transmission line expression of the transmission line in the radar coordinate system is obtained, and the transmission line expression is a parabolic equation or a hyperbolic equation.

[0017] Optionally, the calculation module is further used to obtain the projection points of the mounting points at both ends of the transmission line on the ellipsoidal reference plane of a given elevation, and obtain the coordinates of the two projection points in the radar coordinate system through the range Doppler equation, and construct a straight line equation connecting the two projection points; solve the range deviation function between the straight line equation of the two projection points and the transmission line expression according to the azimuth, and obtain the incident angle and range resolution of the synthetic aperture radar image; determine the elevation function of the transmission line based on the range deviation function, the incident angle and the range resolution.

[0018] Optionally, the calculation module is further used to solve the three-dimensional sag state of the transmission line in the geographic coordinate system according to the transmission line expression, elevation function, range Doppler equation and ellipsoid equation; based on the three-dimensional sag state of the transmission line in the geographic coordinate system and the local rectangular coordinate system conversion parameters, obtain the sag state of the transmission line in the local rectangular coordinate system, and calculate its maximum sag point and minimum sag value.

[0019] The third aspect of the present application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement a method for remote sensing monitoring of transmission line sag as described in the above embodiment.

[0020] The fourth aspect of the present application provides a computer-readable storage medium having a computer program or instruction stored thereon. When the computer program or instruction is executed, it is used to implement the method for remote sensing monitoring of transmission line sag as in the above embodiment.

[0021] Therefore, this application has at least the following beneficial effects:

[0022] The embodiment of the present application determines the positions of the mounting points at both ends of the transmission line and the coordinates of the center point of the scattering spot based on the synthetic aperture radar image of the transmission line, which can realize accurate monitoring of the changing sag state of the transmission line. The mounting points and the known reference plane are used to perform three-dimensional inversion of the transmission line, which can achieve the accuracy of the transmission line sag calculation to the decimeter level or even the centimeter level, which helps to improve the timeliness and accuracy of the safety monitoring of overhead transmission line facilities. In the future, the transmission line sag monitoring function module can be integrated on the satellite-borne or unmanned aerial vehicle SAR platform to realize the edge computing function, and the calculation and analysis of the transmission line sag state can be carried out synchronously when the SAR sensor takes the image, and the calculation and analysis results are directly transmitted to the power grid operation and maintenance team, which greatly increases the real-time nature of remote sensing monitoring, especially suitable for power safety operation and maintenance in remote and complex terrains and harsh environments with inconvenient communication.

[0023] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0025] Figure 1 A flowchart of a method for remote sensing monitoring of transmission line sag provided according to an embodiment of the present application;

[0026] Figure 2A schematic diagram of the coordinates of the imaging center point of the image wire scattering spot provided according to an embodiment of the present application;

[0027] Figure 3 A three-dimensional example diagram of a transmission line in a local coordinate system provided according to an embodiment of the present application;

[0028] Figure 4 The display result of the transmission line expression and elevation function in the image provided according to the embodiment of the present application;

[0029] Figure 5 This is an example diagram of remote sensing monitoring of transmission line sag according to an embodiment of the present application;

[0030] Figure 6 A schematic diagram of the sag timing change of a transmission line provided according to an embodiment of the present application;

[0031] Figure 7 This is an example diagram of a device for remotely sensing and monitoring the sag of a power transmission line according to an embodiment of the present application;

[0032] Figure 8 Schematic diagram of the structure of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0033] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0034] The following describes the method, device, equipment and medium for remote sensing monitoring of transmission line sag of the embodiment of the present application with reference to the accompanying drawings. In view of the problems mentioned in the above background technology, the present application provides a method for remote sensing monitoring of transmission line sag, in which the positions of the mounting points at both ends of the transmission line and the coordinates of the center point of the scattering spot are determined based on the synthetic aperture radar image of the transmission line, so as to accurately monitor the changing sag state of the transmission line. By using the mounting points and the known reference plane to perform three-dimensional inversion of the transmission line, the accuracy of the transmission line sag calculation can be achieved to the decimeter level, which helps to improve the safety and stability of power facilities.

[0035] Specifically, Figure 1 A schematic flow chart of a method for remotely sensing transmission line sag monitoring provided in an embodiment of the present application.

[0036] like Figure 1 As shown, the method for remote sensing monitoring of transmission line sag comprises the following steps:

[0037] In step S101, the positioning deviation of the synthetic aperture radar image is determined according to the ground control point.

[0038] In the embodiment of the present application, the transmission conductor is responsible for transmitting electrical energy, while the transmission ground wire mainly plays a protective role against lightning strikes and some of the internally wrapped optical cables have communication capabilities to ensure the safe operation of the transmission line.

[0039] In the embodiment of the present application, the periodic change of the texture characteristics of the scattered spots of the transmission line in the time-series SAR image reflects the change of the sag state of the transmission line. The embodiment of the present application can use the scattered spots formed by the reflection characteristics of the transmission line in the SAR image, based on the changes in the distance and azimuth positions of the scattered spots of the transmission line in the SAR image imaging at different times and the geographical coordinates of the mounting points at both ends of the transmission line, to invert the three-dimensional information of the transmission line, and realize the measurement of the sag change of the wire with decimeter-level accuracy, and realize the monitoring of the sag change of the transmission line, as follows:

[0040] In one embodiment of the present application, determining the positioning deviation of a synthetic aperture radar image includes: obtaining the actual measured geographic coordinates of a control point in the synthetic aperture radar image; calculating the geometric positioning coordinates of the actual measured geographic coordinates of a ground control point in a radar coordinate system using the control point geographic coordinates and a range Doppler equation; determining the positioning deviation value of the synthetic aperture radar image based on the control point radar scattering imaging center point coordinates and the geometric positioning coordinates, wherein the control point radar scattering imaging center point coordinates are the coordinates of the extreme point of scattering intensity within a preset range of the control point target.

[0041] In the embodiments of the present application, the target preset range can be set according to actual conditions, such as the 20*20 window in the following embodiments, without specific limitation.

[0042] It is understandable that the embodiment of the present application can actually measure the high-precision geographic coordinates of the ground control point C, and mark the ellipsoid coordinates of the point as C (B,L,H) ; Use SAR image imaging parameters and range Doppler model to obtain the sub-pixel pixel coordinates C of point C in the SAR coordinate system g(a,r) ; Through more than 10 times oversampling, the maximum value method is used to obtain the sub-pixel level precision coordinate C of the extreme point of scattering intensity within the preset range of the control point C target s(a,r) ;

[0043] In the embodiment of the present application, the sub-pixel center coordinate C is calculated by comparing the control point C using the Doppler model and the measured geographic coordinates. g(a,r) , and the sub-pixel center coordinate C obtained from the extreme point of scattering intensity s(a,r) , obtain the deviation of the sub-pixel accuracy of the SAR image in azimuth and range directions ε (a,r) :

[0044] ε( a,r )=C s ( a,r )-C g ( a,r )

[0045] For ease of understanding, the embodiment of the present application can combine the three-dimensional point cloud of the wire in a certain area to actually measure the high-precision geographic coordinates of a street lamp C of the ground image control point, and explain the positioning deviation of the synthetic aperture radar image in the embodiment of the present application in detail:

[0046] The high-precision geographic coordinates of a street lamp C, a ground image control point, are actually measured in the three-dimensional point cloud of the wire, and the ellipsoid coordinates of the point are marked as C( B,L,H );

[0047] The right angle position vector of the point in the geocentric space is denoted by R C (C X ,C Y ,C z ) T ;

[0048] Corresponding control point C imaging time t i The instantaneous position vector of the SAR satellite at time is in the geocentric rectangular coordinate system, and the position vector R S Denoted as (S X ,S Y ,S Z ) T ;

[0049] R C With R S Satisfies the range Doppler equation:

[0050] R i 2 -(S X -C X ) 2 +(S Y -C Y ) 2 +(S Z -C Z ) 2 =0

[0051]

[0052] Among them, V S is the velocity vector of the SAR sensor S, which contains components in three directions: and λ is the radar wavelength, f d t i The frequency offset of the radar echo signal at time t, R iThen it is point Ct i Slant range to the satellite at any moment;

[0053] Using the cm-level precision orbit data of SAR satellites, R i It can be accurately located to the cm level through iterative solution, and the corresponding imaging time t i The accuracy can be better than 0.1 nanosecond.

[0054] C (X,Y,Z) According to the above range Doppler equation, find the R and t corresponding to this point. i , and calculate the reference coordinate value C in the radar coordinate system (a,r) , accurate to the sub-pixel level, as shown below:

[0055]

[0056] Among them, R0 is the slant distance of the close point corresponding to the first column of pixels in the SAR image, ρ r is the radar azimuth spatial resolution. t0 is the azimuth starting sampling time corresponding to the first row of pixels in the SAR image, Az is the azimuth viewing number, and PRF is the radar pulse repetition frequency.

[0057] Through local oversampling, such as the reference point C coordinate value (C a ,C r ) as the center, such as selecting a 20*20 window, oversampling 10 times, and using the maximum search method under the oversampled window to traverse and find the maximum point of the scattering intensity, the radar scattering imaging center point C of the reference point C is obtained. g Pixel coordinates

[0058] Compare the sub-pixel center coordinates (C) calculated by using the Doppler model and the measured geographic coordinates of the image control point C a ,C r ), and the sub-pixel center coordinates obtained by the maximum value search method Obtaining the positioning deviation ε of the sub-pixel accuracy of SAR images (a,r) =C s(a,r) -C g(a,r) , by calculating the positioning deviation of a certain area under the TSX image

[0059] In step S102, the geometric positioning error of the synthetic aperture radar image is corrected according to the positioning deviation, and the radar coordinate system coordinates of the mounting points at both ends of the transmission line and their projection points on a given reference ellipsoid are determined according to the geometric positioning parameters of the corrected synthetic aperture radar image.

[0060] Furthermore, the coordinates of the mounting points at both ends of the transmission line and the coordinates of the projection points of the mounting points at both ends of the transmission line are determined according to the positioning deviation of the synthetic aperture radar image, including: acquiring imaging parameters of the synthetic aperture radar image; determining the coordinates of the mounting points at both ends of the transmission line according to the imaging parameters, positioning deviation and range Doppler model; defining an ellipsoid reference plane of a given elevation, wherein the given elevation is lower than the lowest point of suspension of the transmission line, and determining the geographic coordinates of the corresponding points of the mounting points at both ends of the transmission line vertically projected onto the ellipsoid reference plane of the given elevation; determining the radar coordinate system coordinates of the mounting points at both ends of the transmission line and the corresponding points of the mounting points at both ends projected onto the ellipsoid reference plane of the given elevation according to the imaging parameters, the positioning deviation and the range Doppler model.

[0061] On the basis of the above embodiments, the embodiments of the present application can utilize SAR image imaging parameters and range Doppler model, and take into account the positioning deviation ε of the SAR image sub-pixel accuracy. (a,r) , find the coordinates P of the mounting point P at one end of the wire (a,r) ; Using SAR image imaging parameters and range Doppler model, and taking into account the positioning deviation of SAR image sub-pixel accuracy ε (a,r) , find the coordinates Q of the mounting point Q at the other end of the wire (a,r) .

[0062] In the embodiment of the present application, the mounting points P and Q at both ends can also be projected onto the ellipsoidal surface with an elevation of h to obtain P g , Q g Two points and their projection coordinates P in the radar coordinate system g(a,r) ,Q g(a,r) , specifically including the following steps:

[0063] Define an ellipsoidal datum with a given elevation, where the given elevation is lower than the lowest point of the transmission line, and the elevation is recorded as H0; use SAR image imaging parameters and range Doppler model, and take into account the positioning deviation ε of the SAR image sub-pixel accuracy (a,r) , determine the coordinates of the corresponding projection points of the mounting points at both ends of the transmission line vertically projected onto the ellipsoid reference plane of a given elevation;

[0064] Find the projection point P of the mounting point P at one end of the wire on the ellipsoid g The projection point coordinates P g(a,r) ; Using SAR image imaging parameters and range Doppler model, and taking into account the positioning deviation of SAR image sub-pixel accuracy ε (a,r) , find the projection point coordinates Q of the mounting point Q at one end of the wire (a,r) ;

[0065] Furthermore, the embodiment of the present application can also obtain the coordinates of the center point of the scattering spot of the transmission line, that is, the embodiment of the present application can oversample the pixel at the center point of the scattering spot of the transmission line by more than 10 times through the local oversampling method; based on the oversampling data and the maximum value search method, the coordinates S of the center point of the scattering spot of the transmission line in the SAR image are obtained. (a,r) ;like Figure 2 The black dot shown is S (a,r) , respectively showing the scattering spots of the F transmission line in the periods of 20130427, 20130702, 20130815, and 20130906. Figure 2 It can be seen that the center point of the scattering spot is different in each image, that is, the performance is inconsistent when the synthetic aperture radar image is taken at different times.

[0066] In step S103, according to the radar coordinate system coordinates of the mounting points at both ends of the transmission line and their projection points on a given reference ellipsoid, and the coordinates of the center point of the scattering spot of the transmission line, an expression of the transmission line and an elevation function in the radar coordinate system are constructed, and the sag state of the transmission line at the time of synthetic aperture radar image shooting is calculated according to the transmission line expression and the elevation function.

[0067] It can be understood that the embodiment of the present application can obtain the transmission line expression of the transmission line at the time of synthetic aperture radar image shooting according to the coordinates of the center point of the transmission line scattering spot and the radar coordinate system coordinates of the suspension points at both ends of the transmission line; construct a straight line equation according to the radar coordinate system coordinates of the projection points of the mounting points at both ends of the transmission line on the ellipsoid reference plane of a given elevation, and obtain the elevation function of the transmission line in combination with the transmission line expression; according to the transmission line expression obtained at the time of radar image shooting and the calculated elevation function of the transmission line, the sag function of the transmission line at the time of radar image shooting in three-dimensional space is determined by the range Doppler equation, specifically:

[0068] The embodiment of the present application can use the range Doppler model and SAR imaging parameters, combined with the transmission line expression f(a) in the radar coordinate system and the elevation function expression H(a), to obtain the point set i in the geographic coordinate system of the transmission line [XYZ] ; Among them, the elevation function expression H(a) is introduced in detail in the following embodiments.

[0069] In one embodiment of the present application, the elevation function of the transmission line in the radar coordinate system is obtained, including: obtaining the geographic coordinates of the projection points of the mounting points at both ends of the transmission line on the ellipsoid reference plane of a given elevation, and obtaining the coordinates of the two projection points in the radar coordinate system through the range Doppler equation, and constructing a straight line equation connecting the two projection points; solving the range deviation function between the straight line equation of the two projection points and the expression of the transmission line point by point along the azimuth direction, and obtaining the incident angle and range resolution parameters of the synthetic aperture radar image; and determining the elevation function of the transmission line based on the range deviation function, the incident angle and the range resolution parameter.

[0070] In the embodiment of the present application, the connection P g(a,r) , Q g(a,r) Two points, get the straight line equation g(a), where a is the azimuth coordinate corresponding to any point on the line, such as Figure 4 As shown by the white straight line in the middle. The embodiment of the present application can combine the straight line equation g(a) and S (a,r) , to obtain the transmission line elevation function H(a) in the radar coordinate system, specifically including the following steps:

[0071] When the expression f(a) of the transmission line i in the radar coordinate system is defined as a quadratic polynomial function, a is the azimuth coordinate of any point on the line in the radar coordinate system, and f(a) is the range coordinate of any point a on the line i in the radar coordinate system; based on P (a,r) and Q (a,r) and S (a,r) , find the polynomial coefficients β1, β2, β3, and get f(a). The F conductor f of the 20130427 period under the TSX image F (a) If Figure 4 As shown by the white curve in the middle;

[0072] Furthermore, the embodiment of the present application can solve the distance deviation function p(a) between the straight line equation H(a) of the projection point coordinates and the transmission line expression f(a) according to the azimuth, and obtain the incident angle and distance resolution of the synthetic aperture radar image; determine the elevation function of the transmission line based on the distance deviation function, the incident angle and the distance resolution, as follows:

[0073] Solve the distance deviation function p(a) between g(a) and f(a) according to the azimuth:

[0074] p(a)=|g(a)-f(a)|

[0075] By obtaining the incident angle η and range resolution δ in the SAR imaging parameters r ;

[0076] Based on the distance deviation function p(a), η and δ are introduced r , obtain the transmission line elevation function H(a) in the radar coordinate system:

[0077] H(a)=H0+p(a)*δ r / cosη

[0078] Furthermore, according to the transmission line expression, elevation function, range Doppler equation and ellipsoid equation, the point set of the transmission line in the geographic coordinate system is solved.

[0079] Specifically, the embodiment of the present application can use N=1 to 5 azimuth pixels as the step size, that is, a=a+N, and substitute f(a) and H(a) to obtain the three-dimensional point set of the transmission i in the SAR image: i [af(a)H(a)] ; And use the range Doppler model and SAR imaging parameters to obtain the point set in the geographic coordinate system of the transmission line i: i [BLH)] , transform the point set in the geographic coordinate system of the transmission line i into the spatial rectangular coordinate system to obtain the target point set i [XYZ] , achieving precise positioning of the imaging points of the transmission lines in the SAR images and inversion of the three-dimensional model, thereby realizing the construction of SAR two-dimensional data into three-dimensional form.

[0080] Furthermore, a local rectangular coordinate system is established, and the lowest point of the transmission line point set is defined as the origin, and the mounting point P (X,Y,Z) and Q (X,Y,Z) The line connecting XOY is the M axis, and the line perpendicular to the connecting direction is the N axis; the point set i in the geographic coordinate system of the transmission line [XYZ] Transform to local rectangular coordinate system i [mn] ; In the local rectangular coordinate system, i [mn] Fitting obtains the expression L(m) of the transmission line i; connect P (m,n) , Q (m,n) Two points, get the equation of the line k(m); calculate the sag function of the transmission line at the time of SAR imaging q(m) = k(m)-L(m). In the actual execution process, when the expression L(m) function is defined as a quadratic polynomial function (i.e., a parabola equation), where m is the coordinate of any point on the wire in the direction of the transmission line connection in the local coordinate system, L(m) is the azimuth coordinate of any point on the wire in the elevation direction, calculate the polynomial coefficients β1, β2, β3; when the expression L(m) function is defined as a catenary equation function (i.e., a hyperbola equation), where m is the coordinate of any point on the wire in the direction of the transmission line connection in the local coordinate system, L(m) is the azimuth coordinate of any point on the wire in the elevation direction, calculate the catenary equation coefficient δ1.

[0081] Furthermore, the embodiment of the present application establishes a local rectangular coordinate system, defines the lowest point of the transmission line point set as the origin, and the mounting point P(X,Y,Z) and Q (X,Y,Z) The line connecting XOY is the M axis, and the line perpendicular to the line is the N axis. Figure 3 As shown; the point set i in the geographic coordinate system of the transmission line [XYZ] Transform to local rectangular coordinate system i [mn] :

[0082] m i =(X i -X0) / cosα

[0083] n i =Z i -Z0

[0084] Among them, α is the angle between the transmission lines in the XOY plane, X0, Z0 are the coordinates of the origin in the geographic coordinate system. i , Z i is the coordinate value of any point in the geographic coordinate system, m i , n i is the coordinate value of the point in the local coordinate system; in the local rectangular coordinate system, i [mn] Fitting obtains the expression L(m) of the transmission line i; connect P (m,n) , Q (m,n) Two points, get the straight line equation k(m); calculate the transmission line sag function q(m)=k(m)-L(m). Figure 4 Shown is the expression L(m) of the transmission line A in the local coordinate system calculated by the TSX image based on the scattering center point and the mounting points P and Q.

[0085] It can be understood that the embodiment of the present application obtains the sag state of the transmission line in the local rectangular coordinate system and calculates its maximum sag point and minimum sag value based on the three-dimensional space sag state of the transmission line in the geographic coordinate system and the local rectangular coordinate system conversion parameters. Specifically, in the local rectangular coordinate system determined by the mounting points at both ends of the wire, based on the established equation of the transmission line, the SAR imaging time T is obtained at different times. i The transmission line sag function q Ti (m); respectively obtain the special sag value of the sag function of the transmission line at different SAR imaging times. When , the m value is the maximum sag point, corresponding to That is the maximum sag. When m=0, This is the lowest point of the sag.

[0086] Combine the following Figure 5 The application of the remote sensing monitoring method of the transmission line sag in the long time series image in the embodiment of the present application is described in detail, and the specific steps are as follows:

[0087] Step S1: Generate a time baseline map for the SAR data set, select the date with each baseline less than 150m and in the middle of the time series as the main image, and align all SAR images according to the main image; use the ground image control points to correct the SAR image positioning deviation, and obtain the imaging coordinates P of the mounting points P and Q at both ends of the transmission line i in the radar coordinate system (a,r) ,Q (a,r) ;

[0088] Step S2: T i The SAR image at the time is used to obtain the center point S of the scattering spot of the transmission line based on the maximum value method. (a,r) Sub-pixel accuracy coordinates of radar coordinate system;

[0089] Step S3: Calculate the projection point P of the hanging points at both ends of the wire on the ellipsoid with an elevation of h g and Q g Sub-pixel precision radar imaging coordinates P g(a,r) ,Q g(a,r) , and construct the straight line equation g(a) connecting the two points in the radar coordinate system;

[0090] Step S4: For each image, obtain the scale T at the time of imaging i ; Joint P (a,r) ,Q (a,r) And based on T i S extracted from SAR images at any time (a,r) , obtain the transmission line expression f(a) in the radar coordinate system, calculate the pixel interval from f(a) to the straight line equation g(a) along the azimuth direction, and obtain the transmission line elevation function H(a) in the radar coordinate system;

[0091] Step S5: In the local rectangular coordinate system determined by the mounting points at both ends of the wire, establish the equation of the transmission wire and obtain the equations of different SAR imaging times T i The transmission line sag function The special sag values ​​in the sag function of the transmission line at different SAR imaging times are obtained respectively. When , the m value is the maximum sag point, corresponding to That is the maximum sag value. When m=0, This is the minimum sag value.

[0092] Specifically, the special sag values ​​in the sag function of the transmission line at different SAR imaging times are obtained, such as the value of m=0n=0, which is the time-series minimum sag value of the transmission line; when the first-order derivative of the conductor sag function is zero, the point is the maximum sag point; when m is at the midpoint of P and Q, it is the span center sag value of the transmission line. Figure 6As shown in the figure, the time series diagram of the sag change of transmission line A in 65 periods is shown. There are obvious seasonal changes in the figure, where HC_min represents the minimum sag value of transmission line A. The sag change of transmission line A in 5 years is about 2m.

[0093] According to the method for remote sensing monitoring of transmission line sag proposed in the embodiment of the present application, the positions of the mounting points at both ends of the transmission line and the coordinates of the center point of the scattering spot are determined based on the synthetic aperture radar image of the transmission line, so that accurate monitoring of the changing sag state of the transmission line can be achieved. By using the mounting points and known reference planes to perform three-dimensional inversion of the transmission line, the accuracy of the transmission line sag calculation can be achieved to the decimeter level, which helps to improve the safety and stability of power facilities.

[0094] Next, a device for remotely sensing and monitoring the sag of a transmission line according to an embodiment of the present application will be described with reference to the accompanying drawings.

[0095] Figure 7 It is a block diagram of a device for remotely sensing and monitoring the sag of a transmission line according to an embodiment of the present application.

[0096] like Figure 7 As shown, the device 10 for remotely sensing and monitoring the sag of a transmission line includes: a determination module 100 , a correction module 200 and a calculation module 300 .

[0097] Among them, the determination module 100 is used to determine the positioning deviation of the synthetic aperture radar image according to the ground control point; the correction module 200 is used to correct the geometric positioning error of the synthetic aperture radar image according to the positioning deviation, determine the radar coordinate system coordinates of the mounting points at both ends of the transmission line and their projection points on a given reference ellipsoid according to the corrected geometric positioning error, and extract the coordinates of the center point of the scattering spot of the transmission line; the calculation module 300 is used to construct the transmission line expression and elevation function in the radar coordinate system based on the radar coordinates of the mounting points at both ends of the transmission line and their projection points on a given reference ellipsoid and the coordinates of the center point of the scattering spot of the transmission line, and calculate the sag state of the transmission line at the time of shooting the synthetic aperture radar image according to the transmission line expression and the elevation function.

[0098] In one embodiment of the present application, the determination module 100 is further used to obtain the actual measured geographic coordinates of the ground control point in the synthetic aperture radar image; use the geographic coordinates and the range Doppler equation to calculate the geometric positioning coordinates of the actual measured geographic coordinates of the ground control point in the radar coordinate system; determine the positioning deviation value of the synthetic aperture radar image based on the radar scattering imaging center point coordinates and the geometric positioning coordinates of the ground control point, wherein the radar scattering imaging center point coordinates of the ground control point are the coordinates of the scattering intensity extreme point within a preset range of the ground control point target, and the positioning deviation value of the radar image is used to correct the geometric positioning of the synthetic aperture radar image.

[0099] In one embodiment of the present application, the correction module 200 is further used to correct the geometric positioning error of the synthetic aperture radar image according to the positioning deviation, solve the corresponding radar coordinate system coordinates through the range Doppler equation according to the geographic coordinates of the mounting points at both ends of the transmission line and the geographic coordinates of the projection points on a given reference ellipsoid, and extract the coordinates of the center point of the scattering spot of the transmission line.

[0100] In one embodiment of the present application, the calculation module 300 is further used to construct an expression and an elevation function of the transmission line in the radar coordinate system according to the radar coordinate system coordinates of the mounting points at both ends of the transmission line and their projection points on a given reference ellipsoid, and the coordinates of the center point of the scattering spot of the transmission line. According to the expression and the elevation function of the transmission line, the range Doppler equation is used to calculate the set of geographic coordinate points of the sag state of the transmission line at the time when the synthetic aperture radar image is taken.

[0101] In one embodiment of the present application, the calculation module 300 is further used to obtain the coordinates of the center point of the scattering spot of the transmission line as the coordinates of the extreme point of the scattering intensity within a preset range of the scattering spot; using the radar coordinate system coordinates of the center point of the scattering spot of the transmission line and the mounting points at both ends of the line, under the condition that the tangent equation of the sag state function at the center point of the scattering spot is zero or there is an extreme value in the distance direction, the transmission line expression of the transmission line in the radar coordinate system is obtained, and the transmission line expression is a parabolic equation or a hyperbolic equation.

[0102] In one embodiment of the present application, the calculation module 300 is further used to obtain the projection points of the mounting points at both ends of the transmission line on the ellipsoidal reference plane of a given elevation, and obtain the coordinates of the two projection points in the radar coordinate system through the range Doppler equation, and construct a straight line equation connecting the two projection points; solve the range deviation function between the straight line equation of the two projection points and the transmission line expression according to the azimuth, and obtain the incident angle and range resolution of the synthetic aperture radar image; determine the elevation function of the transmission line based on the range deviation function, the incident angle and the range resolution.

[0103] In one embodiment of the present application, the calculation module 300 is further used to solve the three-dimensional sag state of the transmission line in the geographic coordinate system according to the transmission line expression, elevation function, range Doppler equation and ellipsoid equation; based on the three-dimensional sag state of the transmission line in the geographic coordinate system and the local rectangular coordinate system conversion parameters, the sag state of the transmission line in the local rectangular coordinate system is obtained, and its maximum sag point and minimum sag value are calculated.

[0104] It should be noted that the above explanation of the embodiment of the method for remotely sensing the sag of a transmission line is also applicable to the device for remotely sensing the sag of a transmission line of this embodiment, and will not be repeated here.

[0105] According to the device for remote sensing monitoring of transmission line sag proposed in the embodiment of the present application, the changing sag state of the transmission line is monitored based on the synthetic aperture radar image of the transmission line, and the accuracy of transmission line sag calculation can be achieved to the decimeter level or even the centimeter level, which is helpful for the safe operation and maintenance status analysis and disaster warning assessment of overhead transmission line facilities.

[0106] Figure 8 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device may include:

[0107] A memory 801 , a processor 802 , and a computer program stored in the memory 801 and executable on the processor 802 .

[0108] When the processor 802 executes the program, the method for remotely sensing and monitoring the sag of a transmission line provided in the above embodiment is implemented.

[0109] Furthermore, the electronic device further comprises:

[0110] The communication interface 803 is used for communication between the memory 801 and the processor 802 .

[0111] The memory 801 is used to store computer programs that can be executed on the processor 802 .

[0112] The memory 801 may include a high-speed RAM (Random Access Memory) memory, and may also include a non-volatile memory, such as at least one disk memory.

[0113] If the memory 801, the processor 802 and the communication interface 803 are implemented independently, the communication interface 803, the memory 801 and the processor 802 can be connected to each other through a bus and communicate with each other. The bus can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 8 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0114] Optionally, in a specific implementation, if the memory 801, the processor 802 and the communication interface 803 are integrated on a chip, the memory 801, the processor 802 and the communication interface 803 can communicate with each other through an internal interface.

[0115] The processor 802 may be a CPU (Central Processing Unit), or an ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present application.

[0116] The electronic device described in the embodiment of the present application can be placed on a SAR sensor platform to realize remote sensing data capture, carry out edge computing, obtain the sag state of the transmission line and perform status assessment and early warning. It can also be placed in a data processing center to analyze the sag state of the transmission line through the collected remote sensing data.

[0117] The present application also provides a computer-readable storage medium on which computer programs, geographic coordinates of ground control points, and geographic coordinates of transmission line suspension points are stored. When the computer programs and related geographic coordinate data are executed by a processor, the above method of remote sensing monitoring of transmission line sag is implemented. The storage medium can be placed on a SAR sensor platform or in a data processing center or other location.

[0118] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0119] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0120] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0121] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array, a field programmable gate array, etc.

[0122] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0123] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for remote sensing monitoring of transmission line sag, characterized in that: The following steps are involved: Determine the positioning deviation of synthetic aperture radar images based on ground control points; Correcting the geometric positioning error of the synthetic aperture radar image according to the positioning deviation, determining the radar coordinate system coordinates of the mounting points at both ends of the transmission line and their projection points on a given reference ellipsoid according to the corrected geometric positioning error, and extracting the coordinates of the center point of the scattering spot of the transmission line; According to the radar coordinate system coordinates of the mounting points at both ends of the transmission line and their projection points on a given reference ellipsoid, and the coordinates of the center point of the scattering spot of the transmission line, an expression of the transmission line and an elevation function in the radar coordinate system are constructed, and the sag state of the transmission line at the time of synthetic aperture radar image shooting is calculated according to the transmission line expression and the elevation function.

2. The method for remote sensing monitoring of transmission line sag according to claim 1, characterized in that: Determining the positioning deviation of the synthetic aperture radar image according to the ground control point includes: Obtaining the geographical coordinates actually measured of the ground control point; Utilizing the geographic coordinates and the range Doppler equation, calculating the geometric positioning coordinates of the ground control point converted from the actual measured geographic coordinates to the radar coordinate system; The positioning deviation value of the synthetic aperture radar image is determined based on the radar scattering imaging center point coordinates of the ground control point and the geometric positioning coordinates, wherein the radar scattering imaging center point coordinates of the ground control point are the coordinates of the extreme point of scattering intensity within a preset range of the ground control point target, and the positioning deviation value of the radar image is used to correct the geometric positioning of the synthetic aperture radar image.

3. The method for remote sensing monitoring of transmission line sag according to claim 1, characterized in that: The radar coordinates of the mounting points at both ends of the transmission line and their projection points on a given reference ellipsoid are determined based on the corrected geometric positioning parameters, including: Acquiring imaging parameters of the synthetic aperture radar image; Determine the coordinates of the mounting points at both ends of the transmission line according to the imaging parameters, the positioning deviation and the range Doppler model; Define an ellipsoidal reference plane of a given elevation, wherein the given elevation is lower than the lowest point of suspension of the transmission line, and determine the geographic coordinates of corresponding projection points of the mounting points at both ends of the transmission line vertically projected onto the ellipsoidal reference plane of the given elevation; The radar coordinate system coordinates of the mounting points at both ends of the transmission line and the corresponding projection points of the mounting points at both ends projected onto the ellipsoid reference plane at the given elevation are determined according to the imaging parameters, the positioning deviation and the range Doppler model.

4. The method for remote sensing monitoring of transmission line sag according to claim 1, characterized in that: According to the radar coordinate system coordinates of the mounting points at both ends of the transmission line and their projection points on a given reference ellipsoid, and the coordinates of the center point of the scattering spot of the transmission line, an expression and an elevation function of the transmission line in the radar coordinate system are constructed to calculate the sag state of the transmission line at the time of synthetic aperture radar image shooting, including: Obtain the transmission line expression of the transmission line at the time of synthetic aperture radar image shooting according to the coordinates of the center point of the scattering spot of the transmission line and the radar coordinate system coordinates of the suspension points at both ends of the transmission line; Constructing a straight line equation according to the radar coordinate system coordinates of the projection points of the mounting points at both ends of the transmission line on the ellipsoid reference plane at a given elevation, and combining the transmission line expression to obtain the elevation function of the transmission line; According to the transmission line expression obtained at the time of synthetic aperture radar image shooting and the calculated elevation function of the transmission line, the sag function of the transmission line at the time of synthetic aperture radar image shooting in three-dimensional space is determined through the range Doppler equation.

5. The method for remote sensing monitoring of transmission line sag according to claim 4, characterized in that: In the plane of the radar coordinate system, the transmission line expression of the transmission line at the time of synthetic aperture radar image shooting is obtained according to the coordinates of the center point of the scattering spot of the transmission line and the radar coordinate system coordinates of the suspension points at both ends of the transmission line, including: Acquire the coordinates of the center point of the scattering spot of the transmission line, where the coordinates of the center point of the scattering spot of the transmission line are the coordinates of the extreme value point of the scattering intensity within a preset range of the scattering spot; By using the radar coordinate system coordinates of the center point of the scattering spot of the transmission line and the mounting points at both ends of the line, and taking the condition that the tangent equation of the sag state function at the center point of the scattering spot is zero or there is an extreme value in the distance direction, the transmission line expression of the transmission line in the radar coordinate system is obtained, and the transmission line expression is a parabolic equation or a hyperbolic equation.

6. The method for remote sensing monitoring of transmission line sag according to claim 4, characterized in that: The step of constructing a straight line equation according to the radar coordinate system coordinates of the projection points of the mounting points at both ends of the transmission line on the ellipsoid reference plane at a given elevation, and obtaining the elevation function of the transmission line in combination with the transmission line expression, comprises: Obtain the geographic coordinates of the projection points of the mounting points at both ends of the transmission line on the ellipsoid reference plane at a given elevation, obtain the coordinates of the two projection points in the radar coordinate system through the range Doppler equation, and construct the equation of the straight line connecting the two projection points; Solving the distance deviation function between the straight line equation of the two projection points and the transmission line expression point by point along the azimuth direction, and obtaining the incident angle and distance resolution parameters of the synthetic aperture radar image; An elevation function of the transmission line is determined based on the range deviation function, the incident angle and the range resolution parameter.

7. The method for remote sensing monitoring of transmission line sag according to claim 4, characterized in that: Calculating the sag state of the transmission line at the time of synthetic aperture radar image shooting according to the transmission line expression and the elevation function includes: Solving the three-dimensional sag state of the transmission line in the geographic coordinate system according to the transmission line expression, the elevation function, the range Doppler equation and the ellipsoid equation; According to the three-dimensional space sag state of the transmission line in the geographic coordinate system and the conversion parameters of the local rectangular coordinate system, the sag state of the transmission line in the local rectangular coordinate system is obtained, and its maximum sag point and minimum sag point are calculated.

8. A device for remotely sensing and monitoring the sag of a power transmission line, characterized in that: include: A determination module, for determining a positioning deviation of a synthetic aperture radar image according to a ground control point; A correction module, used to correct the geometric positioning error of the synthetic aperture radar image according to the positioning deviation, determine the radar coordinate system coordinates of the mounting points at both ends of the transmission line and their projection points on a given reference ellipsoid according to the corrected geometric positioning error, and extract the coordinates of the center point of the scattering spot of the transmission line; The calculation module is used to construct a transmission line expression and an elevation function in the radar coordinate system based on the radar coordinate system coordinates of the mounting points at both ends of the transmission line and their projection points on a given reference ellipsoid and the coordinates of the center point of the scattering spot of the transmission line, and calculate the sag state of the transmission line at the time of synthetic aperture radar image shooting according to the transmission line expression and the elevation function.

9. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for remote sensing monitoring of transmission line sag as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program or instruction stored thereon, characterized in that: When the computer program or instruction is executed, the method for remotely sensing the sag of a transmission line as described in any one of claims 1 to 7 is implemented.

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