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US 10,379,223 B2Granted
Fourier analysis by spectral transformation (Fast) Photonic Doppler Velocimetry (PDV) with signal fade mitigation
AssigneeLawrence Livermore National Security, LLC
InventorsCorey V Bennett, Natalie B Kostinski
Life of this patent
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Abstract
A state-of-the-art class of photonic Doppler velocimetry (PDV) diagnostic and novel methods to stabilize any class of PDV signal has been developed. The former brings velocimetry to new extremes in maximum velocity and fast time resolution, while maintaining precision velocity resolution, long record length capability, and the ability to record multiple velocities simultaneously. The latter compensates for large changes in signal intensity common in many experiments.
Claims43
A method, comprising:
- directing a first frequency of light onto a surface at a first time to produce a first reflected signal, wherein said surface is not moving relative to a reference point during said first time;
- performing a Fourier transform of said first reflected signal to produce a first pulse in time;
- directing said first frequency of light onto said surface at a second time to produce a second reflected signal, wherein said surface is moving relative to said reference point during said second time, wherein said first frequency of light is Doppler shifted to a second frequency of light according to the velocity of said surface;
- performing a Fourier transform of said second reflected signal to produce a second pulse in time;
- measuring the time difference between said first puke in time and said second pulse in time;
- and
- determining the velocity of said surface from said time difference.
4 more elements
An apparatus, comprising:
- a source for providing a first frequency of light;
- means for (i) directing said first frequency of light onto a surface at a first time to produce a first reflected signal when said surface is not moving relative to a reference point during said first time and (ii) directing said first frequency of light onto said surface at a second time to produce a second reflected signal when said surface is moving relative to said reference point during said second time, wherein said first frequency of light is Doppler shifted to a second frequency of light according to the velocity of said surface;
- means for (i) performing a Fourier transform of said first reflected signal to produce a first pulse in time and (ii) performing a Fourier transform of said second reflected signal to produce a second pulse in time;
- means for measuring the time difference between said first pulse in time and said second pulse in time;
- and
- means for determining the velocity of said surface from said time difference.
3 more elements
An apparatus, comprising:
- means for directing a first frequency of light onto a surface at a first time to produce a first reflected signal when said surface is not moving relative to a reference point during said first time;
- means for performing a Fourier transform of said first reflected signal to produce a first pulse in time;
- means for directing said first frequency of light onto said surface at a second time to produce a second reflected signal when said surface is moving relative to said reference point during said second time, wherein said first frequency of light is Doppler shifted to a second frequency of light according to the velocity of said surface;
- means for performing a Fourier transform of said second reflected signal to produce a second pulse in time;
- means for measuring the time difference between said first pulse in time and said second puke in time;
- and
- means for determining the velocity of said surface from said time difference.
4 more elements
Dependencies are inferred from the claim text.