The Application of Split Band Interferometry in Large-scale Bridge Monitoring

The bridge displacement responses can move from several centimeters to several meters induced by a combination of four major types of loading due to wind, temperature, highway, and railway. One of the main challenges of InSAR technique is phase unwrapping. One can take advantage of this wide band to split it into sub-bands and determine the phase-frequency gradient between the sub-band interferograms. This simulates a SAR system with a much longer carrier wavelength than the actual one, which makes it possible to monitor the meter-scale deformation. This paper presents the theory and method of split bandwidth interferometry in detail, and the effectiveness and advantage of split bandwidth interferometry was verified in feasibility of monitoring structural deformation of Tsingma Bridge under the influence of different factors.