Source location in an urban setting using time reversal with small sensor arrays

2005 ◽  
Vol 118 (3) ◽  
pp. 1966-1966
Author(s):  
Mark E. Todaro
Keyword(s):  
Time Reversal ◽  
Sensor Arrays ◽  
Source Location ◽  
Urban Setting

Time reversal enabled elastic wave data communications using sensor arrays

2013 ◽  
Vol 134 (5) ◽  
pp. 3980-3980 ◽  
Author(s):  
Yuanwei Jin ◽  
Yujie Ying ◽  
Deshuang Zhao
Keyword(s):  
Elastic Wave ◽  
Time Reversal ◽  
Sensor Arrays ◽  
Data Communications ◽  
Wave Data

Development of the Source Reconstruction System by Combining Sound Source Localization and Time Reversal Method

2016 ◽  
Vol 34 (1) ◽  
pp. 35-40
Author(s):  
S.-C. Lin ◽  
G.-P. Too ◽  
C.-W. Tu
Keyword(s):  
Impulse Response ◽  
Response Function ◽  
Source Localization ◽  
Sound Source ◽  
Time Reversal ◽  
Impulse Response Function ◽  
Source Location ◽  
Sound Source Localization ◽  
Target Sound ◽  
Reconstructed Signal

AbstractThis study explored the target sound source location at unknown situation and processed the received signal to determine the location of the target, including the reconstructed signal of source immediately. In this paper, it used triangulation sound sources localization and time reversal method (TRM) to reconstruct the source signals. The purpose is to use a sound source localization method with a simple device to quickly locate the position of the sound source. This method uses the microphone array to measure signal from the target sound source. Then, the sound source location is calculated and is indicated by Cartesian coordinates. The sound source location is then used to evaluate free field impulse response function which can replace the impulse response function used in time-reversal method. This process reduces the computation time greatly which makes possible for a real time source localization and source signal separation.

Estimation of hydro‐fracture source location with time reversal mirrors

2008 ◽  
Author(s):  
Weiping Cao ◽  
Tong W. Fei ◽  
Yi Luo ◽  
Mohammed N. Alfaraj ◽  
Gerard T. Schuster ◽  
...  
Keyword(s):  
Time Reversal ◽  
Source Location

Time reversal processing for source location in an urban environment

2005 ◽  
Vol 118 (2) ◽  
pp. 616-619 ◽  
Author(s):  
Donald G. Albert ◽  
Lanbo Liu ◽  
Mark L. Moran
Keyword(s):  
Urban Environment ◽  
Time Reversal ◽  
Source Location

A SCENARIO STUDY FOR IMPROVING COST-EFFECTIVENESS IN ACOUSTIC TIME-REVERSAL SOURCE RELOCATION IN AN URBAN ENVIRONMENT

2012 ◽  
Vol 20 (02) ◽  
pp. 1240003 ◽  
Author(s):  
LANBO LIU ◽  
HAO XIE ◽  
DONALD G. ALBERT ◽  
PAUL R. ELLER ◽  
JING-RU C. CHENG
Keyword(s):  
Cost Effectiveness ◽  
Urban Environment ◽  
Time Reversal ◽  
Sensor Array ◽  
Cost Effective ◽  
Urban Setting ◽  
Minimum Number ◽  
Single Sensor ◽  
Processor Unit ◽  
Single Receiver

Through finite difference time domain (FDTD) numerical simulation, we have studied the possible observation settings to improve the cost effectiveness in time-reversal (TR) source relocation in a two-dimensional (2D) urban setting under a number of typical scenarios. All scenario studies were based on the FDTD computation of the acoustic wave field resulted from an impulse source, propagated through an artificial village composed of 15 buildings and a set of sources and receivers, a typical urban setting has been extensively analyzed in previous studies. The FDTD numerical modeling code can be executed on an off-the-shelf graphic processor unit (GPU) that increases the speed of the time-reversal calculations by a factor of 200. With this approach the computational results lead to some significant conclusions. In general, using only one non-line-of-sight (NLOS) single receiver is not enough to do a quality work to re-locate the source via time-reversal. This is particularly true when there are more than one path between the source and this receiver with similar wave energy travel time. However, when the single sensor is located in an acoustic channel, reverberation inside the waveguide may increase the effective aperture of the single receiver enough to give a good location. It is equivalent to say that the waveguide and the single receiver form a "virtual array". It appears that a sensor array with a minimum number of three receivers might be the most cost-effective way to carry out TR source relocation in an urban environment. The most optimal geometry of a sensor array with a minimum number of three receivers could be an equal side-length triangle. Simple analysis showed that by this setup it is possible to catch sound sources from almost all possible azimuths. Effective source relocation essentially depends on the geometry, relativity to the scatters, etc. of the sensing array. Generally, adding another single sensor relatively far away from the main array will not improve the results. It is practically useful and achievable to have a sensor array mounted on the outside of a single building, and in these cases successful source relocations were obtained. As stated by the fundamental TR theory, increasing the number of scatters, here, increasing the number of buildings will definitely be helpful to increase the effectiveness of TR source relocation.

Seismic velocity estimation using time-reversal focusing

Geophysics ◽  
2018 ◽  
Vol 83 (4) ◽  
pp. U43-U50 ◽  
Author(s):  
Ariel Lellouch ◽  
Evgeny Landa
Keyword(s):  
Wave Equation ◽  
Time Reversal ◽  
Seismic Velocity ◽  
Signal To Noise Ratio ◽  
Onset Time ◽  
Velocity Model ◽  
Source Location ◽  
Velocity Estimation ◽  
Adequate Model ◽  
Traveltime Tomography

Seismic velocity estimation is a challenging task, especially when no initial model is present. In most cases, a traveltime tomography approach is used as a significant part of the workflow. However, it requires noise-sensitive, time-consuming picking and uses a ray approximation of the wave equation. Time reversal (TR) is a fundamental physical concept, based on the wave equation’s invariance under TR operation. If the recorded wavefield is reversed and back-propagated into the medium, it will focus at its original source location regardless of the complexity of the medium. We use this property for seismic velocity analysis, formulated as an inversion problem with focusing at the known source location and onset time as the objective function. It is globally solved using competitive particle swarm optimization and an adequate model parameterization. This approach has the advantages of using the wave equation, being picking-free, handling low signal-to-noise ratio and requiring neither information on the source wavelet nor an initial velocity model. Although the method is discussed in the framework of direct source-receiver path acquisition, the foundations for its use with conventional reflection data are laid. We have determined the method’s usefulness and limitations using synthetic and field crosshole acquisition examples. In both cases, inversion results are compared with a standard traveltime tomography approach and illustrate the advantages of using TR focusing.

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