Research On Snow Information Extraction Based On Insar Technology In Transmission Channel Area

The transmission corridor area in China was affected by the snow and ice disaster every year. The continuous heavy snow has made the transmission area covered with ice,which has led to the broken transmission line, the collapsed transmission tower and the paralyzed transmission system and thus caused enormous economic losses in our country. As the South Regional transmission corridor are mainly located in complex mountainous terrain with harsh climate, which made the staff difficult to carry out effective monitoring,remote sensing technology provides an effective means for snow disaster monitoring. Compared with optical remote sensing, synthetic aperture radar(SAR) has strong penetration and the advantages of all-weather and all-day monitoring which help it become an effective way to monitor the ice and snow disaster of the transmission corridor under unexpected conditions. The main content of this article is,for one thing, to study the extracting algorithm of transmission corridor based on INSAR technology, and for another, the algorithm of extracting the information of transmission tower deformation caused by snow and ice.In this article, the transmission channel area in Dajingliangzi, Xichang City,Sichuan Province was chosen as the key monitoring area and 22 sequentially Terra-SAR X-band high-resolution SAR images were obtained. Based on X-band SAR images, the microwave scattering and coherence characteristics in transmission channel area were studied. Besides, an algorithm based on INSAR technology for extracting snow covered information of transmission corridor was proposed to solve the misjudgment between low coherent features and snow area in the traditional snow extraction algorithm. Two interference SAR image pairs with the same time period and the similar spatial baseline are selected in the algorithm to reclassify the low coherent non-snow areas according to the characteristics of multi-temporal coherence and eventually to effectively distinguish the low-coherence non-snow area and snow covered area in transmission channel area.The results were validated by GF-1 optical image combined with confounding matrix evaluation method to reach an accuracy of 82.44% so we can realize the snow disaster monitoring of the transmission channel area according to the meteorological information and the distribution of snow around the transmission tower.Additionally, an indirect way was adopted to monitor the inclination of tower caused by snow covering based on D-InSAR technology. First, the interference fringe pattern of the transmission tower was extracted. Besides, the means of eliminating the flat earth effect by frequency was considered to remove the vertical height phases of transmission tower using Fourier transform and circumferential displacement and then the authentic differential phase was obtained after phase unwrapping. Finally, the indirect information extraction of the transmission tower covered by ice and snow was achieved according to the results and the meteorological information.