scholarly journals GPS Derived Seismic Signals for Far Field Earthquake Epicenter Location Estimation

2021 ◽  
Vol 3 (1) ◽  
pp. 7-12
Author(s):  
Sha’ameri A.Z. ◽  
Wan Aris W.A. ◽  
Musa T.A.
Keyword(s):  
Estimation Method ◽  
Seismic Signal ◽  
The United States ◽  
Location Estimation ◽  
United States Geological Survey ◽  
Time Of Arrival ◽  
Far Field ◽  
Infrastructure Development ◽  
Time Frequency ◽  
Epicenter Location

A reliable epicenter estimation method is proposed for Global Positioning System (GPS) derived seismic signal for far-field regional earthquake. The main contribution is the use of time-frequency analysis to estimate the time of arrival (TOA) using multilateration technique. The data from the 2004 Sumatra Andaman earthquake captured from four GPS continuously operating reference stations (GPS CORS) were used in the analysis. To validate the accuracy of the proposed method, the estimated epicenter location was compared with the data released by the United States Geological Survey (USGS). The estimated location shows an error of about 0.0572 degrees in latitude and 0.2848 degrees in longitude. The proposed analysis method could complement existing seismometer measurements, improve in understanding of geo-seismic phenomena, and plan future infrastructure development.

Acoustic emission–based impact location estimation on composite structures

2019 ◽  
Vol 18 (5-6) ◽  
pp. 1652-1668
Author(s):  
Jingru Zhou ◽  
V John Mathews ◽  
Daniel O Adams
Keyword(s):  
Acoustic Emission ◽  
Composite Structures ◽  
Estimation Method ◽  
Estimation Algorithm ◽  
Location Estimation ◽  
Accurate Estimation ◽  
Attractive Alternative ◽  
Time Of Arrival ◽  
Impact Location ◽  
The Impact

In this article, an acoustic emission–based impact location estimation algorithm is presented for use with composite structures. The algorithm is formulated as a constrained optimization problem by utilizing sensor locations and times of arrival of impact signals at the sensors. The impact locations are estimated without any information about wave propagation velocity in the structure. A modification of the algorithm to overcome difficulties produced by waveform reflections enables accurate estimation of impact locations close to the structure’s boundaries. The capability of this algorithm to accurately estimate impact locations is demonstrated numerically and experimentally. Experiments performed at different temperatures showed that the algorithm is robust to temperature changes. An automatic time-of-arrival estimation method is also presented. The performance capabilities of the method and its computational simplicity make this approach an attractive alternative to other methods available in the literature for practical structural health monitoring applications.

scholarly journals Trend Analysis and Simulation of Human Vulnerability Based on Physical Factors of Riverbank Erosion Using RS and GIS

2021 ◽  
Author(s):  
Tayabur Rashid Chowdhury ◽  
Zia Ahmed ◽  
Sabina Islam ◽  
Shetu Akter ◽  
Shrinidhi Ambinakudige ◽  
...  
Keyword(s):  
Query Language ◽  
Satellite Image ◽  
The United States ◽  
Present Condition ◽  
Primary Data ◽  
United States Geological Survey ◽  
Physical Factors ◽  
Infrastructure Development ◽  
Landsat Images ◽  
Vulnerable Households

AbstractThis study aims to analyze the pattern of bank erosion and simulate the physical aspects of vulnerability in the lower Meghna River, Bangladesh using remote sensing (RS) and geographic information systems (GIS). The physical factors of vulnerability were analyzed using GIS-based Structured Query Language (SQL). A questionnaire survey, GPS survey and field observation survey were conducted for collecting the primary data in the study area. The secondary data were mainly satellite image collected from the United States Geological Survey (USGS) website. Using time series Landsat images (MSS, TM and OLI-TIRS), this study analyzed 36 years of erosion and accretion process in the Mehendiganj Upazila region from 1980 to 2016. The result indicates that an enormous amount of land (4470.47 ha) was submerged by the river and average land loss rate was 124.18 ha/year. The study quantifies the number of vulnerable households beneath the present condition and how much it will be altered after a positive/negative change with the factors of vulnerability related to the households. Simulation data reveals that under the present physical condition, 43.88% of households were identified as severely vulnerable. The output of this study can be used in the classification of vulnerable households and for the improvement of the physical infrastructure development process near the erosion prone areas, also helps to mitigate environmental disaster in the developing countries.

scholarly journals Source Geolocation in Urban Environments Using Multipath Fingerprinting

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Ram M. Narayanan ◽  
Brian R. Phelan ◽  
Erik H. Lenzing
Keyword(s):  
Mobile Communications ◽  
A Priori ◽  
Estimation Method ◽  
Location Estimation ◽  
Estimation Accuracy ◽  
Time Of Arrival ◽  
Angle Of Arrival ◽  
Feature Vectors ◽  
Area Of Interest ◽  
Estimation System

A method for determining the location of Global Systems for Mobile Communications (GSM) mobile transmitters is proposed. Our approach estimates the location of a source without the use of multilateration or Line-of-Sight (LOS) techniques. A Multipath Characteristic Database (MCD) containing the multipath feature vectors, for each possible transmitter location within an area of interest, is populated via ray-tracing software simulations. The multipath characteristics of interest are angle-of-arrival (AOA) (azimuth) and time-of-arrival (TOA). By minimizing the “distance” between estimated and simulated multipath feature vectors, an estimate for the actual source location can be obtained. The development of the estimation method is presented, followed by a detailed analysis of its estimation accuracy. Since the proposed method utilizes a simulated multipath signature database based upon the knowledge of the environment and the terrain, the need fora priorisoundings from the area of interest is eliminated, thus making this location estimation system suitable for application in denied territories. Location accuracies compare favorably with the requirements for the location of wireless 9-1-1 callers as recommended by the Federal Communications Commission (FCC).

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