Detection system for lightning
First Claim
1. A direction finder for determining the direction relative to said direction finder of lightning discharges to ground characterized by one or more strokes having a substantially vertical portion extending from the ground and one or more branches above the substantially vertical portion, said substantially vertical portion and said branches each producing a field, said direction finder comprising:
- means for detecting the field produced by a stroke; and
means coupled to said detecting means and responsive only to the field generated by the substantially vertical portion of the stroke for generating an indication of the direction of said portion.
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Reexamination
Accused Products
Abstract
A lightning detection system utilizes a gated magnetic direction finder for determining the range and direction of lightning discharges to ground. Logic circuitry is provided for controlling gating circuits within the direction finder so that the direction measurement is made during the initial few microseconds of the return stroke waveform, thereby minimizing errors caused by nonvertical lightning channels to ground, branches and intracloud discharges. Distance measurements are made by analyzing the amplitude of the detected return stroke waveform, or by utilizing two or more geographically separated direction finders and triangulation techniques. The waveforms of the signals received by the direction finder are analyzed to determine whether the discharge is ground stroke or another type of discharge, or background noise. Further circuitry can be used to distinguish between various types of ground strokes, such as first strokes or subsequent strokes in a flash.
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Citations
82 Claims
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1. A direction finder for determining the direction relative to said direction finder of lightning discharges to ground characterized by one or more strokes having a substantially vertical portion extending from the ground and one or more branches above the substantially vertical portion, said substantially vertical portion and said branches each producing a field, said direction finder comprising:
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means for detecting the field produced by a stroke; and means coupled to said detecting means and responsive only to the field generated by the substantially vertical portion of the stroke for generating an indication of the direction of said portion. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 65, 66, 67)
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18. A direction finder for determining the direction relative to said direction finder of lightning discharges to ground having one or more component strokes comprising:
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means responsive to orthogonal components of the field produced by a lightning discharge for generating electrical signals having waveforms representative of the orthogonal components of the field produced by at least one of said component strokes; and means responsive only to the portions of the waveforms of said orthogonal components representative of the initial portion of one of said strokes for determining the direction of said discharge. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 68, 69, 70, 71, 72, 76)
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29. A lightning detection system comprising:
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means responsive to the field produced by a lightning discharge for generating an electrical signal having a waveform representative of said field; and means for analyzing the shape of said waveform and providing a signal indicative of a lightning discharge to ground only when the shape of said waveform has a predetermined characteristic, wherein said analyzing means includes; means responsive to said electrical signal for providing an enabling signal to said system when said waveform exceeds a predetermined level; means responsive to said electrical signal for detecting a peak of said waveform and providing a peak indicative signal in response thereto; and means operatively coupled to said enabling signal providing means and to said peak detecting means for providing a signal indicative of a lightning discharge to ground when said peak indicative signal occurs within a predetermined time interval following the generation of said enabling signal. - View Dependent Claims (30, 31, 32, 33, 34, 73, 74, 75)
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35. The method of determining, relative to a point of observation, the direction of a lightning discharge to ground characterized by one or more strokes having a substantially vertical portion extending from the ground and one or more branches above the substantially vertical portion, comprising the steps of:
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detecting at said point of observation the field produced by a lightning discharge to ground; and utilizing only the portion of the field produced by the substantially vertical portion of the discharge to obtain an indication of the direction to the lightning discharge. - View Dependent Claims (36)
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37. The method of measuring the direction, relative to a point of observation, of a lightning discharge to ground characterized by one or more strokes having a substantially vertical portion extending from the ground and one or more branches comprising the steps of:
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detecting at said point of observation orthogonal components of the field produced by a lightning discharge; generating electrical signals having waveforms representative of the orthogonal components of said field; and utilizing only the portions of the waveforms of the orthogonal components representative of the initial portion of one of said strokes for determining the direction of said discharge. - View Dependent Claims (38, 39, 40, 41, 42, 43, 44, 45, 46, 47)
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48. The method of classifying lightning discharges comprising the steps of:
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detecting the field produced by a lightning discharge; generating an electrical signal having a waveform representative of said field; and analyzing the shape of said waveform and providing an indication of a lightning discharge to ground when the shape of the waveform has a predetermined characteristic, wherein the step of analyzing the shape of said waveform includes the steps of; sensing the amplitude of said waveform, determining when the amplitude of said waveform exceeds a predetermined level, determining the peak of said waveform, and providing said indication of a lightning discharge to ground only if said waveform reaches its peak before the end of a predetermined time interval after the waveform exceeds said predetermined level. - View Dependent Claims (49, 50, 51, 52, 53, 77, 78, 79, 80)
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54. A lightning detection system comprising:
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means for detecting the field produced by a lightning discharge and for providing signals representative of the amplitude and direction of said field relative to said system; means for sampling portions of said signals and providing representations of said sampled portions means for utilizing said representations to generate an indication of the direction of said discharge relative to said system; means operatively coupled to said detecting means and to said sampling means for sensing the amplitude of said field and for rendering said sampling means operative to sample said portions of said signals only after the amplitude of said field exceeds a predetermined level, wherein said amplitude sensing means includes means for detecting the peak of said field and for rendering said sampling means operative to sample said signals upon the occurrence of said peak. - View Dependent Claims (55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 81, 82)
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Specification