Method for detecting a distant target and measuring the target distance using inelastically scattered light
AssigneeAlakai Defense Systems, Inc.
InventorsKenneth R. Pohl, Christopher Neglia
Life of this patent
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Abstract
The present invention comprises a novel approach for determining range to a target using the inelastic scattering of light from the target and/or inelastic scattering of light from molecules between the light emitting source and the target. This is a useful approach in that the range measurement is independent of the retroreflectivity or absorptivity of the target. Using this methodology allows optical detection and rangefinding of targets which by intention or otherwise cannot be detected using conventional LIDAR rangefinding.
Claims23
A method of measuring the distance from a sensor to a target comprising:
- a. detecting inelastically scattered light from the target and/or from an intermediate medium such as air;
- and
- b. determining the distance based on the time-dependence of the intensity of the detected light.
An apparatus for estimating range comprising:
- a. a pulsed monochromatic source,
- b. an optical transmitter subsystem to direct light from the source towards a target,
- c. an optical receiver subsystem which has wavelength selective components which allow inelastic scattered light from the air to be detected and distinguished from inelastic scattered light from the target and from elastically scattered light,
- d. a detector which generates a time-dependent signal or multiplicity of signals proportional to the wavelength-selected time-dependent inelastic scattered light, and
- e. a signal processor subsystem which produces an estimated distance to the target based on the time-dependent signal.
A system for determining range comprising:
- a. a pulsed monochromatic source,
- b. an optical transmitter subsystem to direct light from the source towards a target,
- c. an optical receiver subsystem which has wavelength selective components which allow inelastic scattered light from the air to be detected and distinguished from inelastic scattered light from the target and from elastically scattered light and time-selective components which pass light to a detector only during selected periods of time,
- d. a detector which generates a signal or multiplicity of signal proportional to the total light falling on the detector during a period of time,
- e. a control subsystem which varies the delay in timing of the time-selective component after the pulsed source over a multiplicity of delay times, and
- f. a signal processing system which produces an estimated distance to the target based on the measured signals for each of the multiplicity of delay times.
Dependencies are inferred from the claim text.