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Application of Polarization Analysis to Direction-Finding in the Urban Environment

Session: Advances in Understanding Near-Field Ground Motions: Observation, Prediction and Application II

Type: Oral

Date: 4/22/2021

Presentation Time: 03:00 PM Pacific

Description: 

Polarization analysis is frequently used in both exploration geophysics and earthquake seismology. Although each of these areas covers the near-surface, the technique is also useful in the very near field in terms of perimeter security. Oftentimes the security applications are located in urban environments with a great deal of noise. The purpose of this research was to determine the applicability of polarization analysis to direction-finding in an urban environment. We present results of an experiment conducted in an urban environment where the majority of the noise came from two major roads with near constant traffic of tractor-trailers. We compare results of a basic azimuthal scanning method to a polarization technique based on the covariance matrix.

The results of the polarization techniques greatly depend on several user-defined parameters. These parameters include the type and bandwidth of filtering and the length of the window. Urban noise presents a significant challenge as the same inputs in terms of filtering and window length can result in different azimuthal outputs for the same source at different times. Though challenging, localization of repeated signals in the near-field is not impossible.

Permission to publish was granted by Director, Geotechnical & Structures Laboratory.

Presenting Author: Rebekah F. Lee

Student Presenter: No

Authors