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Full-Text Articles in Physical Sciences and Mathematics

Nonlinear Least Squares 3-D Geolocation Solutions Using Time Differences Of Arrival, Michael V. Bredemann Apr 2020

Nonlinear Least Squares 3-D Geolocation Solutions Using Time Differences Of Arrival, Michael V. Bredemann

Mathematics & Statistics ETDs

This thesis uses a geometric approach to derive and solve nonlinear least squares minimization problems to geolocate a signal source in three dimensions using time differences of arrival at multiple sensor locations. There is no restriction on the maximum number of sensors used. Residual errors reach the numerical limits of machine precision. Symmetric sensor orientations are found that prevent closed form solutions of source locations lying within the null space. Maximum uncertainties in relative sensor positions and time difference of arrivals, required to locate a source within a maximum specified error, are found from these results. Examples illustrate potential requirements …


Satellite Observation Of Ch4 And Co Anomalies Associated With The Wenchuan Ms 8.0 And Lushan Ms 7.0 Earthquakes In China, Y. Cui, Dimitar Ouzounov, N. Hatzopoulos, K. Sun, Z. Zou, J. Du Jun 2017

Satellite Observation Of Ch4 And Co Anomalies Associated With The Wenchuan Ms 8.0 And Lushan Ms 7.0 Earthquakes In China, Y. Cui, Dimitar Ouzounov, N. Hatzopoulos, K. Sun, Z. Zou, J. Du

Mathematics, Physics, and Computer Science Faculty Articles and Research

Spatial and temporal variations of total column of CH4 and CO (TotCH4 and TotCO) associated with the 12 May 2008 Wenchuan and 20 April 2013 Lushan earthquakes in western Sichuan, China were investigated using satellite data from AQUA AIRS in order to understand the lithospheric and atmospheric interactions during the seismic activity. The Wenchuan MS 8.0 and Lushan MS7.0 earthquakes occurred in the Longmenshan fault zone. It was observed that large amounts of gases emitted from the earth's crust into the atmosphere before, during and after the earthquakes. The anomalies of TotCH4 and TotCO occurred along the …