Resumen de Application of differential synthetic aperture radar interferometry (dinsar) to the monitoring of ground and structure movements
During the last decades, satellite-based Synthetic Aperture Radar (SAR) technology has been fully developed in the academic world with the implementation of the algorithms and methodologies that allow the exploitation of satellite-based radar information. However, in some applications, such as the monitoring of ground civil structures, the transition between the academic and the professional work is far from being complete. The lack of a clear standardization of the potential and limits of the technique along with the limited amount of ground truth data from actual constructions work have slowed down the common operational use of satellite-based SAR sensors in the monitoring of construction works. This thesis aims at shedding light to this matter.
An innovative approach is proposed to exploit the long data archives with data from more than 25 years from different sensors generating historical deformation maps. This scenario also provides the opportunity of carrying out a benchmarking analysis pointing out the characteristics of the main frequency bands and the outcomes of different algorithms. This can provide an end user with valuable information to select the best combination of sensor and processing algorithm.
A concise validation effort of the application of satellite-based Persistent Scatterer Interferometry (PSI) to the monitoring of tunneling works is carried out. The construction works of the M-30, which implied the underground of up to 50 km of roads, represent the validation scenario. The estimated PSI deformations have been compared against the data from actual instruments used during the construction period. This validation work proves that high accuracies of a few millimeters can be achieved with the state of the art PSI algorithms. In addition, the limitations of the technique, such as the latency of the estimations update, and the limited availability of coherence points in decorrelated areas are detailed. As a result of this analysis, an optimal monitoring process is proposed based on the integration of satellite-based and a reduced amount of on-ground instruments for the assets that require high frequent estimation updates.
The applicability of the PSI technique to the most challenging urban scenario, a city center, is assessed. These areas have higher decorrelation statistics than other urban areas due to the characteristics of the facades and rooftops and the crowded streets that prevent from obtaining coherent points in transit areas. The tunneling works of the railway between Atocha and Chamart\'in and the enlargement of the waiting areas of the Sol metro stations are the scenarios used. The availability limitations of the technique are clearly seen in this scenario since some of the building affected by the construction works are not covered by coherent points. Nevertheless, it has been shown that PSI can complement conventional instruments providing deformation estimations over large areas.
Finally, the city center scenario is also used for the definition and validation of a set of classification indexes that allow an objective interpretation of the PSI results and reduce the dependency of the results on the algorithm and sensor used in the processing.
