Kinematic approach to the group velocity of high-frequency space-time Love (sh) and Rayleigh (sv) waves

1991 ◽  
Vol 57 (3) ◽  
pp. 3183-3186
Author(s):  
Z. A. Yanson
Keyword(s):  
Group Velocity ◽  
High Frequency ◽  
Space Time ◽  
Frequency Space ◽  
Kinematic Approach

Adaptive Processing with Power Rectified Multi-frequency Space-time Data

2013 ◽  
Vol 34 (10) ◽  
pp. 2470-2474
Author(s):  
Wen-tao Du ◽  
Gui-sheng Liao ◽  
Zhi-wei Yang
Keyword(s):  
Space Time ◽  
Adaptive Processing ◽  
Time Data ◽  
Frequency Space

scholarly journals STAP for Airborne Radar Based on Dual-Frequency Space-Time Coprime Sampling Structure

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 138673-138681
Author(s):  
Mingxin Liu ◽  
Bin Tang ◽  
Xiaoxia Zheng ◽  
Qiang Wang ◽  
Siyuan Wang ◽  
...  
Keyword(s):  
Space Time ◽  
Airborne Radar ◽  
Dual Frequency ◽  
Frequency Space ◽  
Coprime Sampling ◽  
Sampling Structure

Ray equations in retarded Snell midpoint coordinates

Geophysics ◽  
1984 ◽  
Vol 49 (12) ◽  
pp. 2100-2108
Author(s):  
Alfonso González‐Serrano ◽  
Mathew J. Yedlin
Keyword(s):  
Wave Equation ◽  
Acoustic Wave ◽  
Group Velocity ◽  
High Frequency ◽  
Frame Of Reference ◽  
Velocity Analysis ◽  
Acoustic Wave Equation ◽  
Arbitrary Angle ◽  
Frequency Limit ◽  
Velocity Function

Group velocity (ray) equations describe the dynamic behavior of wave‐equation extrapolators in the high‐frequency limit. They are found in general from the dispersion relation of an arbitrary acoustic wave equation. Wave‐equation operators require a background extrapolation velocity. As an application of the group velocity equations, a sensitivity analysis to the background‐operator velocity illustrates the trade‐off between uncertainty in velocity and precision in imaging. Exact wave extrapolators are most useful when the exact velocity function is known. Wave‐equation imaging for velocity analysis in Snell midpoint coordinates requires velocity‐insensitive extrapolation operators. In this frame of reference, approximations of the exact acoustic wave equation are referenced to an arbitrary angle of propagation. Group velocity equations show that in Snell midpoint coordinates, using wide‐reference propagation angles, the fifteen‐degree wave equation gives satisfactory velocity‐independent images. The forty‐five degree wave equation does not appreciably improve the image.

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