Time-Series Monitoring Of Large Gradient Mining Subsidence Based On SAR Technology

Mining subsidence monitoring,which is different from other surface deformation,has the characteristics of complicated geological condition,fast subsidence and large gradient.In recent years InSAR have achieved quite mature development and application in urban surface deformation,earthquake,glacier movement etc.,however it seems ineffective when applied on large gradient deformation like mining subsidence monitoring limited by the technical principle itself.Accordingly,this paper puts the technology called Offset-tracking as the core content,promotes the application of SAR technique on large gradient mining subsidence area by some slight improvements and the combination with D-InSAR.The contents of this paper are as follows:(1)Research status and theoretical principle of SAR technology are introduced.Firstly,we introduce research status of D-In SAR,SABS,Offset-tracking and mining subsidence predicting parameters inversion,point out the merits and defects of these technologies.Then we introduce basic principles of D-InSAR and Offset-tracking,analyze limitations of traditional D-InSAR at the same time.(2)Some improvements of Offset-tracking are made.At first we make an analysis of Offset-tracking error model,and then registration method based on select list is taken to improve registration accuracy,at last the system error are eliminated by quadric surface fitting.After these improvements,the effect of errors in Offset-tracking is eliminated to a certain degree,which provide accuracy guarantee to time-sequence process later.(3)Since traditional D-InSAR method show great advantage in small surface deformation,and Offset-tracking method has strong detecting capability in large gradient deformation monitoring,a kind of time-series Offset-tracking method based on phase fusing is proposed.It get final deformation phase by add wrapped phase values got from D-InSAR and integer ambiguities got from Offset-tracking,thus time-series Offset-tracking method based on phase fusing is proposed.Then we use small baseline subsets method to calculate time-series result,thus minimize errors brought from space-time baseline.(4)Based on the subsidence value,we extracted subsidence basin data such as some angular values as well as major influence radius,besides,probability integral parameters are calculated using empirical formulas.At last,mining subsidence parameter inversion and subsidence prediction are made by combining traditional mining subsidence theory with mathematical method.By these steps,the real-time prediction method and it's accuracy are guaranteed.