Surface Change Detection Using InSAR Technology

With the needs of rapid population growth and economic development, surface changes which include surface deformation and surface use changes become increasingly intensified. As a result, it highlights the importance of the real-time and effective monitoring of the surface changes. InSAR technology has all- weather, high-precision, high-resolution and other characteristics in surface deformation monitoring. It is one of the important methods to monitoring the ground deformation and revealing the development law of the spatial and temporal surface changes. Based on its phase coherence, InSAR technology is usually applied to detect surface deformation with a high accuracy. However, when surface d eformation magnitude is too large or ground cover is severely broken, the SAR interferometry images will have a loss of coherent phenomena, which makes it impossible to get any information of the surface changes. Therefore, this paper attempts to make use of the amplitude information and decorrelation information to detect the surface changes. The identify of mine subsidence and the detection of urban land use changes are two typical application examples of surface changes detection in this paper and the following conclusions can be achieved:1. This paper presents a new idea that we can use radar interferometry decorrelation information to detect the significant surface deformation occurred in the coal mine area. Verified by some examples, the results coinc ide with the actual location of the coal mine, indicating that the radar interferometry decorrelation information can provide an effective basis for recognition of large scale subsidence areas.2. Through comparative analysis of time series coherence map, this article speculates that the relevant law between mining surface subsidence and coal mining activities. After verification, the result of speculation corresponds with the actual situation of corresponding coal mining. It proves that the time series coherence map information can effectively detect the trend and scope of the mining working face and the subsidence area, which is very significant to the prediction and prevention of disasters and the reasonable exploitation of coal mine.3. Under certain radar system and environment variables conditions, different objects have different radar echo intensity and temporal coherence properties. This paper summarizes and analyzes their variation in time and space, making the theoretical foundation for urban change detection.4. In this paper, it proposed a method of monitoring urban land use changes by using radar interferometry coherent information and intensity information. Making Xi’an Q ujiang New District as an example, this article carries on a test on urban land use changes detection and the results are very consistent with the actual situation. Due to the detection by SAR intensity information is susceptible to speckle and the coherence-based change detection is affected by scattering properties, the result also exists miscalculation. Based on this, the paper attempts to combine these two methods and the results show that the identification accuracy of the combined method can be further improved.