Research On Extraction Of Vegetation Elevation Information Of Transmission Line Corridors Based On Synthetic Aperture Radar

Excessive growth of dangerous vegetation in transmission line corridors may result in power outages.It will seriously threaten the stability of the grid operation.With the construction of the smart grid and the UHV project,the safety detection of transmission lines across dense vegetation growth areas such as mountainous areas and uninhabited areas has brought serious challenge to the transmission line detection technology.Traditional manual detection and airborne Li DAR detection methods for dangerous vegetation around transmission lines have problems of low efficiency and small detection range.Therefore,research on the highly efficient and wide-area detection method of vegetation around transmission line corridors based on synthetic aperture radar is of great significance for ensuring the safe and stable operation of the large power grid.This article first introduces the basic theory of polarimetric SAR interferometry.Based on the basic principle of polarimetric SAR interferometry,two vegetation height models and three forest vegetation height inversion algorithms were analyzed.According to the characteristics of dual-polarization SAR data,S-RVoG model was used to improve the three-stage algorithm,and an improved three-stage algorithm based on dual-polarization is studied.The simulated SAR data of different slopes were established by the remote sensing simulation software Pol SARpro.The feasibility of three algorithms for vegetation height inversion of the terrain slope area was studied.And the improved algorithm was compared with the three-stage algorithm to verify the effectiveness and accuracy of the improved algorithm.Then,using ALOS PALSAR dual-polarization data,a transmission line corridor was selected for application analysis.The results show that the determination R~2coefficient of the selected quadrat height was 0.679,and the root mean square error was 1.923m.Secondly,based on the characteristics of vegetation growth and distribution around the transmission line corridor,the effect of vegetation density on the RVoG model was studied.A three-layer DS-RVoG model was proposed to characterize the transmission line vegetation by considering the vegetation density and terrain factors.Based on the model,a shuffled frog leaping algorithm was used to improve three-stage algorithm to inverse vegetation height.The simulation software established simulated SAR data with different densities vegetation.Compared with the three-stage algorithm based on the RVoG model,the effectiveness and accuracy of the improved algorithm was verified.Finally,according to the improved algorithm based on the three-layer DS-RVoG model,a method for detecting the vegetation height around transmission line corridors was proposed.The Gaofen-3 qual-polarization SAR data was applied to detect four different vegetation density areas in the 220k V Jiangyou-tianming transmission line in Mianyang,Sichuan Province.The vegetation height of the quadrat was detected.The feasibility and accuracy of the proposed detection method were verified by combining the airborne Li DAR data and the in situ measured data.The highest determination coefficient R~2 of the selected quadrat height in the four study areas was 0.832,and the lowest root mean square error was 2.005 m.The research results can provide technical support for early warning of vegetation risk in satellite telemetry transmission line corridors.