Heritage site deformation monitoring method based on distributed scatterer temporal interferometric SAR technology

Abstract

The invention discloses a heritage site deformation monitoring method based on the distributed scatterer temporal interferometric SAR technology. The method comprises the following steps: firstly determining monitoring areas of a heritage site and collecting relevant information; performing mutual registration, radiation correction and image cutting preprocessing on collected SAR images then, and extracting permanent scatterer objects and distributed scatterer objects; removing topography and flat ground phases of the distributed scatterer objects, and optimizing phase estimation through adoption of maximum likelihood estimation and the LBFGS technology; fusing the permanent scatterer objects at initial phases and distributed objects at optimized phases then, setting short time / space baseline thresholds so as to generate small baseline set interference pairs, performing phase upwrapping on the small baseline set interference pairs, and removing errors caused by topographical and atmospheric delays; and finally solving an average annual deformation rate and a deformation history change value. Deformations of heritage sites can be monitored through the method, the problem that suburbs have rare extractable points is overcome, the method is suitable for multi-scale stable monitoring from a single historic building to a whole heritage site, and the method is in favor of assessing of heritage site influence factors.

Description

technical field [0001] The invention relates to the field of heritage site monitoring, in particular to a heritage site deformation monitoring method based on distributed scatterer time series interferometric SAR technology. Background technique [0002] Heritage sites, such as cultural relics and natural wonders, are irreplaceable wealth of great significance and great value in human history. More than 5,000 years of historical civilization and vast territory have made China a major heritage country. As of July 2015, 48 items have been included in the "World Heritage List", ranking second in the world, second only to Italy. Unfortunately, heritage sites are becoming increasingly unstable due to natural disasters and human activities. Natural hazards include landslides, earthquakes, floods, severe weather, and sudden changes in climate. Human activities include wars, overexploitation of resources, urbanization and uncontrolled tourism. These external factors put many heri...

AI Technical Summary

Problems solved by technology

Traditional deformation measurement methods such as leveling, GPS or geophysical technology have the following disadvantages: 1) low efficiency, high cost, and need to consume a lot of manpower and material resources, which are severely limited by the field work environment; Area deformation field, it is difficult to obtain long-term sequence deformation in the time dimension, and it is difficult to display the law of space-time changes

[0005] However, there are still some problems that need to be solved urgently in the existing technology in heritage site monitoring: 1) The requirements for the number of SAR images are relatively high (usually more than 25 scenes, such as PSInSAR and SqueeSAR); The coherence phenomenon is serious, the permanent scatterers (Persistent Scatterers, PS) are rare, and the number of points that can be used for parameter inversion is insufficient, which affects the accuracy of phase unwrapping and deformation estimation

However, distributed scatterers have poor coherence and low signal-to-noise ratio, requiring complex and special filtering processing

[0007] It can be seen that the existing MTInSAR technology still has defects in the monitoring of heritage terrain deformation. How to create a more applicable monitoring method of heritage terrain deformation based on distributed scatterer time-series interferometric SAR technology has become the goal pursued by the industry

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