US3856402A — Clear air turbulence detector

Claim 1

Independent Claim 262 words

A clear air turbulence detector comprising: laser light generating means for providing as an output a narrow beam of light energy of a predetermined frequency; pulse generating means for providing a train of electrical pulses at a preselected rate and of a preselected width; modulation means responsive to said laser light generating means and said pulse generating means for providing pulses of said beam of light energy corresponding in time to the pulse output of said pulse generating means; optical transmission means responsive to the output of said modulation means for transmitting pulses of narrow beam light in a selected direction and for receiving reflected returns of said pulses of said light; detection means responsive to an output of said optical transmission means Of reflected returns of light for providing as an output, discrete electrical signals of a frequency proportional to the velocity of aerosols from which the light returns are reflected; filter means responsive to the output of said detection means for providing a plurality of outputs, each output being selectively responsive to signal frequencies within a selected discrete band of frequencies within a selected overall range of frequencies of the detector; gating means coupled to said filter means for passing a selected sequence of outputs of said filter means as a set of outputs for each of a plurality of selected ranges from the clear air turbulence detector of aerosols providing reflected returns of light; and indicating means responsive to said filter means for indicating the velocities of aerosols providing returns and the distance of said aerosols from said detector.

Claim 2

Dependent Claim 262 words

A clear air turbulence detector comprising: laser light generating means for providing as an output a narrow beam of light energy of a predetermined frequency; pulse generating means for providing a train of electrical pulses at a preselected rate and of a preselected width; modulation means responsive to said laser light generating means and said pulse generating means for providing pulses of said beam of light energy corresponding in time to the pulse output of said pulse generating means; optical transmission means responsive to the output of said modulation means for transmitting pulses of narrow beam light in a selected direction and for receiving reflected returns of said pulses of said light; detection means responsive to an output of said optical transmission means Of reflected returns of light for providing as an output, discrete electrical signals of a frequency proportional to the velocity of aerosols from which the light returns are reflected; filter means responsive to the output of said detection means for providing a plurality of outputs, each output being selectively responsive to signal frequencies within a selected discrete band of frequencies within a selected overall range of frequencies of the detector; gating means coupled to said filter means for passing a selected sequence of outputs of said filter means as a set of outputs for each of a plurality of selected ranges from the clear air turbulence detector of aerosols providing reflected returns of light; and indicating means responsive to said filter means for indicating the velocities of aerosols providing returns and the distance of said aerosols from said detector.

Claim 3

Dependent Claim 126 words

A clear air turbulence detector as set forth in claim 1 wherein: said modulation means is connected to said laser light generating means and modulates the output of said laser light generating means to provide said pulses of said beam of light energy to said light amplifier; said optical transmission means includes a light amplifier; and said pulse generating means includes means for providing pulse operating power to said light amplifier during pulse intervals in which said laser light generating means is providing pulsed light inputs to said light amplifier; whereby said light amplifier is turned on during periods when it is receiving input pulses of light and is turned off for at least most of the interval between pulses of input light to said amplifier.

Claim 4

Dependent Claim 52 words

A clear air turbulence detector as set forth in claim 2 wherein said light amplifier comprises a plurality of tubes, arranged serially, wherein light is directed from end-to-end through the tubes and said tubes are filled with a gas adapted to provide tuned light amplification at the output frequency of said laser.

Claim 5

Dependent Claim 58 words

A clear air turbulence detector as set forth in claim 3 wherein said light amplifier includes at least two said tubes positioned side-by-side and at least two adjacent ends of said tubes each includes right-angle mirrors for coupling the light output from the end of one tube to a light input at the end of the other tube.

Claim 6

Dependent Claim 30 words

A clear air turbulence detector as set forth in claim 4 further comprising means supporting said mirrors for adjustably positioning said mirrors with respect to the ends of said tubes.

Claim 7

Dependent Claim 86 words

A clear air turbulence detector as set forth in claim 1 wherein said filter means comprises a plurality of sets of bandpass filters, each set comprising a plurality of bandpass filters with each bandpass filter of a given set having substantially the same selected bandpass, the bandpass filters of a given set together covering said selected range of frequencies, and wherein the bandpass filters of different sets differ in bandwidth and number of filters to provide, selectively, as between sets of filters, degrees of velocity selectivity.

Claim 8

Dependent Claim 160 words

A clear air turbulence detector as set forth in claim 6 wherein: said pulse generating means comprises means for providing a like plurality of different pulse widths to that of the number of sets of bandpass filters; said gating means includes gating signal generating means responsive to and synchronized with said pulse generating means for generating a selected discrete number of signals between said pulses; said gating means is further responsive to said gating signal generating means for passing, sequentially, in a progressive sequence varying directly with the output frequency of said detection means, the outputs of a selected said set of of bandpass filters a plurality of times between said pulses whereby a plurality of velocities at a plurality of ranges are discretely provided as outputs; and switching means connected to said pulse generating means for selecting a said pulse width and connected to said gating means For selecting a particular said set of bandpass filters to be gated.

Claim 9

Dependent Claim 249 words

A clear air turbulence detector as set forth in claim 1 wherein: said filter means comprises: a plurality of bandpass filters, together, covering, in equal range increments, said selected range of frequencies; a like plurality of frequency converters to that of said bandpass filters, each converter being responsive to one of said bandpass filters for converting the frequencies passed to the same band of frequencies produced by the other said converters, each band, however, remaining representative of a different velocity range; and first, second and third sets of narrow bandpass filters of progressively greater bandwidth, respectively, fed from the output of each said converter and wherein the number of narrow bandpass filters times the bandwidth of one of these filters of a given set equals the output bandwidth of a said converter; said pulse generating means includes means for generating first, second and third said pulses of progressively greater width, respectively; mode switching control means for selectively controlling said pulse generating means for providing said first, second or third pulses and for controlling said gating means for selectively causing said first set of bandpass filters to be progressively gated between the generating of successive said first pulse width pulses, said second set of bandpass filters to be progressively gated between the generation of successive said second pulse width pulses and said third set of bandpass filters to be progressively gated between the generation of successive said third pulse width pulses; whereby selected degrees of velocity signal selectivity is obtained.

Claim 10

Dependent Claim 193 words

A clear air turbulence detector as set forth in claim 8 wherein: said gating means includes gating signal generating means responsive to and synchronized with said pulse generating means for selectively generating a first discrete set and number of signals between said first pulses, a second discrete set and number of signals between said second pulses, and a third discrete set and number of signals between said third pulses; and said gating means includes means responsive to said first set of signals for sequentially gating a first plurality of times the bandpass filters of said first set of narrow bandpass filters, said gating means is responsive to said second set of signals for gating a second plurality of times the bandpass filters of said second set of narrow bandpass filters, and said gating means is responsive to said third set of signals for gating a third plurality of times the bandpass filters of said third set of narrow bandpass filters; whereby said first, second and third sets of narrow bandpass filters are selectively gated for the selective indication of signals representative of different turbulence velocities occurring in different distance ranges from said detector.

Claim 11

Dependent Claim 173 words

A clear air turbulence detector as set forth in claim 9 wherein said indicating means comprises a cathode ray tube display including a controlled electron beam and further including: first sweep signal generating means responsive to said pulse generating means for moving said electron beam along one axis of said cathode ray tubes display for each generation of a said pulse to provide a beam position on said cathode ray tube indicative of range of a reflection from an aerosol received by said detector; second sweep signal generating means responsive to each said signal from said gating signal generating means for moving said electron beam along an opposite axis to said one axis, thus providing a selected number of sweeps between said pulses; and electron beam gating means responsive to said reflected returns of said pulses of light for concurrently gating ''''on'''' said electron beam; whereby the range of a given reflected light return is measured along said one axis and the velocity of a said return is measured along said second axis.

Claim 12

Dependent Claim 177 words

A clear air turbulence detector as set forth in claim 10 wherein: said first pulses are each of a duration of 8 microseconds, said second pulses are each of a duration of 4 microseconds and said third pulses are each of a duration of 2 microseconds; said selected range of frequencies is between 5 and 15 MHz; there are five each of said bandpass filters and converters, each covering 2 MHz increments; there are 80-125 KHz said first narrow bandpass filters, 40-250 KHz said second narrow bandpass filters and 20-500 KHz said third narrow bandpass filters; the pulse repetition rate of said pulse generating means is 200 pulses per second; and there are 4,000 said first signals between succeeding said first pulses to provide 25 velocity indications at 4,000 foot range increments outward from said detector, there are 8,000 said second signals between succeeding second pulses to provide 50 velocity indications at 2,000 foot range increments, and there are 16,000 of said third signals between succeeding third pulses to provide velocity indications at 1,000 foot range increments.

Claim 13

Dependent Claim 69 words

A clear air turbulence detector as set forth in claim 1 wherein said detection means includes mixer means and means responsive to the speed of movement of the turbulence detector for converting said discrete electrical signals provided by said detection means into a said selected overall range of frequencies as the output of said detection means which is compensated for the said speed of movement of the turbulence detector.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1977-12-23	1978-06-24	1978-12-24	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1981-12-23	1982-06-24	1982-12-24	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1985-12-23	1986-06-24	1986-12-24	$7700.00	Window Closed / Lapsed

Clear air turbulence detector

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