Research On The Theory And Method Of Environment Correction And Data Processing Of GB-SAR

Deformation monitoring is the important supporting of monitoring projects, such as landslide, subsidence, earthquakes and so on. It has great significance in disaster forecasting and project construction that using the technology acquisition target deformation information, then researching and analyzing of the monitoring results to grasp deformation of the target. At present, the common appearance of monitoring tools (such as GPS, Total Station, etc.) need to laid observation pier on slope surface. Affecting the cost and construction and other factors, the number of monitoring sites is sparser, as well as gets a small amount of monitoring data acquisition. When the observation pier damaged, for losing data acquisition, the data processing becomes much too difficult. In addition the monitoring tools belong to contact measurement, when the deformation of the surface cannot be laid monitoring points, the method be invalid. Three-dimensional laser scanning technology, without the target surface laid monitoring point, as a non-contact measurement can acquire the three-dimensional model of target point cloud data in different time to build the target, by the difference between the models calculate the overall anti-deformation target. However there are some limitations in engineering applications using this technology by measuring accuracy and distance limitations. In addition photogrammetric techniques cannot be continuous observation during day and night, as well as the photo-quality construction is poor affected seriously by a complex environment. Therefore this technology in engineering applications is difficult to be valid.In recent decades,the InSAR (Interferometric synthetic aperture radar) technology as a kind of active microwave remote sensing technology, with all-weather, all-day, high precision measurement of advantage, in terms of surface subsidence, DEM generation has been widely used; However, the technology cannot meet the target of a small scale deformation monitoringby some factors, such as the fixed satellite orbit, long satellite return cycle and low spatial resolution. In recent years, the ground-based synthetic aperture radar (GB-SAR)overcomes the drawback of deformation monitoring using the space-borne SAR in the target small area. The domestic and foreign scholars carry on research ofdeformation monitoring using the GB-SAR technology in small scale target, including error analysis, landslides, dam deformation the feasibility study of deformation monitoring. The research has shown that GB-SAR can get the deformation information of the target with the advantages of non-contact, high precision and fast. However, the technology is currently not applied to the complex environment of target deformation monitoring and deformation monitoring of the target periodically, according to the key technologies such as the environmental impact of GB-SAR interferometry, PS selection method and data processing theory and methodshave not yet systematic research according to the characteristics of the GB-SAR measurement mode, so the technology has certain limitation in the application of deformation monitoring. Aiming at these problems, through in-depth study the key technology of GB-SAR interferometry, it hasgreat significance and application value to designs a set of perfect data processing method for the deformation monitoring using GB-SAR, which make GB-SARto be applied to the different needs of the deformation monitoring.For the practical application of GB-SAR in the complex environmental target deformation monitoring and periodic deformation monitoring, the main key technologies to solve have effective environmental correction method selection, PS and PS analysis method. Therefore, this paper mainly through the in-depth study of the three key technologies, improving the GB-SAR technology for target deformation monitoring data processing method, makes the technology can be applied to different monitoring mode of target in deformation monitoring. The main research contents are as follows:1) It is introducedthe basic theory ofSAR, such as system components, electromagnetic characteristics, the geometry of observation and observation model and radar target imaging relations, analyzing of GB-SAR with different space-borne SAR in the aspect of basic theory. At the same time, it is introduced the key technologies of the GB-SAR such as step frequency continuous wave technique, synthetic aperture radar technology, the interference measuring technology in detail,then comparesthe technical characteristics between GB-SAR and traditional measurement methods, to sum up the advantages and disadvantages of GB-SAR technology.2) It is researched that the characteristic of interferometric phase in small area and a wide range areas affected by the environment. A multipoint environment correction methodconsidering to the azimuth of GB-SAR is offered based on the goal and the stability of the point of the spatial relationship in small ovservation scene.Meanwhile A environment correction according to the observation scenarios bearing to partition is put forward, then using theheight information for each environment area to correct theinterferometric phase in a wide range areas. Finally, it is verified theenvironment correction method proposed in this paperusing experimental data.3) It is researched the characteristics of PS in GB-SAR image, proposed PS selection methods aiming at the control points and the target point in the area,using multi-threshold through analyzingthe PS selection methods of space-borne SAR and according to feature of GB-SAR image. Finally, it is verified the PS selection method proposed in this paperusing experimental data.4) It is proposed the data processing method for long and short time baseline data of GB-SAR.separately, according to the characteristics of the GB-SAR imageunder different observation model.Then it is compared and analyzed between the data processing method proposed in this paper and the traditional method, to verify the proposed data processing method.5) It is researched the application using GB-SAR technology on different targets such as landslides, dams, bridges. According to different observation targets and monitoring environment,it is designed different monitoring programsand data processing method to put GB-SAR technique intodifferent target deformation monitoring scheme, meanwhileit is verified that the technology canbe used to monitor deformation of different target feasibility.