Return pulse shape analysis for falling edge object discrimination of aerosol LIDAR
First Claim
1. A remote sensing system for obtaining range information about an object in a predetermined direction, the system comprising:
- a pulsed signal source for emitting at least one pulsed signal;
a transceiver for directing the at least one pulsed signal in the predetermined direction and for receiving at least one return signal associated with the at least one pulsed signal from along the predetermined direction;
at least one detector, each for gathering the at least one return signal from the transceiver; and
a signal processor for;
correlating at least one falling edge of the at least one return signal gathered by each of the at least one detectors, with a falling edge of the at least one pulsed signal and determining therefrom a range from the system to a reflecting entity in the predetermined direction;
comparing a feature of one of the at least one falling edge of the at least one return signal against at least one threshold to characterize the reflecting entity as being from the object or from an obscuring aerosol cloud; and
discarding the range associated with the at least one falling edge of the at least one return signal if the reflecting entity is characterized as being from the aerosol cloud.
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Accused Products
Abstract
A LIDAR optical remote sensing system and method analyzes the falling edge profile of a return LIDAR signal that may be indicative of an object or an aerosol cloud, which is generally more diffuse. Using the falling edge profile permits burnthrough to an object that may be obscured by the aerosol cloud. The profile is compared against at least one threshold that may correspond, in various embodiments, to a negative slope of the falling edge, an integrated power under the falling edge, or a range estimate error for varying transmitted power values, varying transmitted pulse lengths and/or varying receiver detector field of view values.
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Citations
36 Claims
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1. A remote sensing system for obtaining range information about an object in a predetermined direction, the system comprising:
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a pulsed signal source for emitting at least one pulsed signal; a transceiver for directing the at least one pulsed signal in the predetermined direction and for receiving at least one return signal associated with the at least one pulsed signal from along the predetermined direction; at least one detector, each for gathering the at least one return signal from the transceiver; and a signal processor for; correlating at least one falling edge of the at least one return signal gathered by each of the at least one detectors, with a falling edge of the at least one pulsed signal and determining therefrom a range from the system to a reflecting entity in the predetermined direction; comparing a feature of one of the at least one falling edge of the at least one return signal against at least one threshold to characterize the reflecting entity as being from the object or from an obscuring aerosol cloud; and discarding the range associated with the at least one falling edge of the at least one return signal if the reflecting entity is characterized as being from the aerosol cloud. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for obtaining range information about an object in a predetermined direction, the method comprising steps of:
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emitting at least one pulsed signal in the predetermined direction; receiving at least one return signal associated with the at least one pulsed signal from along the predetermined direction; gathering the at least one return signal at at least one detector; correlating at least one falling edge of the at least one return signal gathered by each of the at least one detectors, with a falling edge of the at least one pulsed signal and determining therefrom a range from the system to a reflecting entity in the predetermined direction; comparing a feature of one of the at least one falling edge of the at least one return signal against at least one threshold to characterize the reflecting entity as being from the object or from an obscuring aerosol cloud; discarding the range associated with the at least one falling edge of the at least one return signal if the reflecting entity is characterized as being from the aerosol cloud; and returning either the range associated with the object or the absence of an object for a predetermined distance in the predetermined direction. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A signal processor operatively coupled to a remote sensing system for obtaining range information about an object in a predetermined direction, comprising:
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a correlator for determining, from a falling edge of at least one pulsed signal emitted in the predetermined direction and at least one falling edge of at least one return signal from a reflecting entity associated with the at least one pulsed signal gathered by at least one detector from along the predetermined direction, a range from the system to the reflecting entity in the predetermined direction; and a comparator for comparing a feature of each of one of the at least one falling edge of the at least one return signal against at least one threshold to characterize the reflecting entity as being from the object or from an obscuring aerosol cloud, whereupon the range characterized as being from the aerosol cloud is discarded.
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36. A non-transitory computer-readable medium in a processor operatively coupled to a remote sensing system for obtaining range information about an object in a predetermined direction, the medium having stored thereon, computer-readable and computer-executable instructions which, when executed by the processor, cause the processor to perform acts comprising:
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determining, from a falling edge of at least one pulsed signal emitted in the predetermined direction and at least one falling edge of at least one return signal from a reflecting entity associated with the at least one pulsed signal gathered by at least one detector from along the predetermined direction, a range from the system to the reflecting entity in the predetermined direction; comparing a feature of each of one of the at least one falling edge of the at least one return signal against at least one threshold to characterize the reflecting entity as being from the object or from an obscuring aerosol cloud; and discarding the range if the reflecting entity is characterized as being from the aerosol cloud.
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Specification