Strobe light and laser beam detection for laser receiver

A method for distinguishing between illumination of photodetectors by a moving, relatively thin beam of laser light, and illumination of photodetectors by an omnidirectional pulse of light, comprising the steps of:

• positioning a plurality of photodetector elements in a generally vertical row, said elements being connected into a plurality of arrays and each photodetector element providing an electrical output when illuminated,
• for each array providing a portion of the electrical output of each photodetector element in the array as a first reference signal, and providing a portion of the electrical output of each photodetector element in the array as a second reference signal,
• determining the sum of the first and second reference signals from said photodetector arrays,
• determining the difference between the largest of the first and second reference signals from said photodetector arrays and the smallest of the first and second reference signals from said photodetector arrays,
• dividing said sum of the first and second reference signals from said photodetector arrays by said difference between the largest and smallest of the first and second reference signals to provide a quotient, and
• when said quotient is less than a predetermined level, interpreting the quotient as indicating illumination of said photodetectors by a moving, relatively thin beam of laser light.

A method for distinguishing between illumination of photodetectors by a moving, relatively thin beam of laser light, and illumination of photodetectors by an omnidirectional pulse of light, comprising the steps of:

• positioning a plurality of photodetector elements in a generally vertical row, said elements being connected into a plurality of arrays and each photodetector element providing an electrical output when illuminated,
• for each array providing a portion of the electrical output of each photodetector element in the array as a first reference signal, and providing a portion of the electrical output of each photodetector element in the array as a second reference signal,
• determining the sum of the first and second reference signals from said photodetector arrays,
• determining the difference between the largest of the first and second reference signals from said photodetector arrays and the smallest of the first and second reference signals from said photodetector arrays,
• dividing said sum of the first and second reference signals from said photodetector arrays by said difference between the largest and smallest of the first and second reference signals to provide a quotient, and
• when said quotient is greater than a predetermined level, interpreting the quotient as indicating illumination of said photodetectors by an omnidirectional pulse of light.

A device for detecting a moving, relatively thin beam of laser light, and distinguishing between illumination of photodetectors by such a moving, relatively thin beam of laser light, and illumination of photodetectors by an omnidirectional pulse of light, comprising:

• a plurality of photodetector arrays arranged in a generally vertical row, each array including a plurality of photodetector elements arranged in a generally vertical array row, such that the photodetector elements in said arrays are arranged in a generally vertically oriented, extended row, each of said photodetector elements providing an electrical output when illuminated,
• a plurality of weighting circuits, each weighting circuit associated with a respective one of said plurality of photodetector arrays, each weighting circuit providing a portion of the electrical output of each photodetector element in the associated array as a first reference signal related to the spacing of the photodetector element from a first end of said array row, and providing a portion of the electrical output of each photodetector element in the associated array as a second reference signal related to the spacing of the photodetector element from the second end of said array row, the weighting circuit associated with each array row being connected to the weighting circuits associated with adjacent array rows, and
• circuitry, associated with and responsive to the reference signals from connected weighting circuits, for determining the ratio of sum of the reference signals to the difference between the largest and smallest of the reference signals, and interpreting this ratio as indicating illumination of said photodetectors by a moving, relatively thin beam of laser light when said ratio is less than a predetermined level, and interpreting the ratio as indicating illumination of said photodetectors by an omnidirectional pulse of light when said ratio is greater than said predetermined level.

A method for distinguishing between illumination of photodetectors by a moving, relatively thin beam of laser light, and illumination of photodetectors by an omnidirectional pulse of light, comprising the steps of:

• positioning a plurality of photodetector elements, said elements being connected into a plurality of arrays and each photodetector element providing an electrical output when illuminated,
• for each array providing a first reference signal, and a second reference signal, the difference between the reference signals indicating the position of photodetector elements in the array being illuminated,
• determining the sum of the first and second reference signals from said photodetector arrays,
• determining the difference between the largest of the first and second reference signals from said photodetector arrays and the smallest of the first and second reference signals from said photodetector arrays,
• dividing said sum of the first and second reference signals from said photodetector arrays by said difference between the largest and smallest of the first and second reference signals to provide a quotient, and
• when said quotient is greater than a predetermined level, interpreting the quotient as indicating illumination of said photodetectors by an omnidirectional pulse of light.

A method for distinguishing between illumination of photodetectors by a moving, relatively thin beam of laser light, and illumination of photodetectors by an omnidirectional pulse of light, comprising the steps of:

• positioning a plurality of photodetector elements, said elements being connected into a plurality of arrays and each photodetector element providing an electrical output when illuminated,
• for each array providing a first reference signal, and a second reference signal, the difference between the reference signals indicating the position of photodetector elements in the array being illuminated,
• determining the sum of the first and second reference signals from said photodetector arrays,
• determining the difference between the largest of the first and second reference signals from said photodetector arrays and the smallest of the first and second reference signals from said photodetector arrays,
• dividing said difference between the largest and smallest of the first and second reference signals by said sum of the first and second reference signals from said photodetector arrays to provide a quotient, and
• when said quotient is less than a predetermined level, interpreting the quotient as indicating illumination of said photodetectors by an omnidirectional pulse of light.