Apparatus and method for measuring visibility and present weather
First Claim
1. An apparatus for measuring visibility and present weather, said apparatus comprising:
- a light source for transmitting a light ray toward a space to be measured;
a first light detector for measurement of light of the light ray which is forward scattered from elements in said space;
first computing means, connected to said first light detector, for generating a signal representing the detected forward scattered light;
a second light detector for detecting a portion of the light ray retro-reflected directly backward toward said light source due to atmospheric elements, and for generating a signal representing the detected retro-reflected portion of the light ray; and
second computing means for receiving the signal from said second light detector and computing the propagation delay between the transmitted light ray and the retro-reflected portion of the light ray in order to determine a distance to the atmospheric elements, said apparatus measuring the present weather based upon said signal generated by said first computing means and the propagation delay computed by said second computing means.
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Accused Products
Abstract
The invention relates to an apparatus and method for measuring visibility and present weather. The apparatus includes a light source (1) for directing a light ray toward the object (9) to be measured, a detector (3) for measurement of light which is forward scattered from the object (9), and computing elements (12-15) adapted to differentiate the signal representing the forward scattered light from signals representing stray or ambient light. The apparatus may include a pulsed light source, a receiver (19) for receiving directly backward reflected/scattered light pulses, and computing elements (11) for computing the propagation delays of the different backward reflected components in the received pulse-shaped optical signal.
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Citations
20 Claims
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1. An apparatus for measuring visibility and present weather, said apparatus comprising:
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a light source for transmitting a light ray toward a space to be measured; a first light detector for measurement of light of the light ray which is forward scattered from elements in said space; first computing means, connected to said first light detector, for generating a signal representing the detected forward scattered light; a second light detector for detecting a portion of the light ray retro-reflected directly backward toward said light source due to atmospheric elements, and for generating a signal representing the detected retro-reflected portion of the light ray; and second computing means for receiving the signal from said second light detector and computing the propagation delay between the transmitted light ray and the retro-reflected portion of the light ray in order to determine a distance to the atmospheric elements, said apparatus measuring the present weather based upon said signal generated by said first computing means and the propagation delay computed by said second computing means. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of measuring present weather, said method comprising the steps of:
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generating light pulses; impinging the light pulses on a space to be measured; receiving and measuring light of the light pulses which is forward-scattered from elements in the space to be measured; receiving backward directed portions of the light pulses which are directed backward due to atmospheric elements, and generating a signal representing the detected backward directed portions; computing the backward propagation delays of the backward directed portions of the pulsed light based upon the signal; and
determining present weather based upon the measured light of the light pulses which is forward-scattered, and the signal representing the detected backward directed portions of the light pulses. - View Dependent Claims (8, 9, 10, 11)
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12. An apparatus for measuring visibility and present weather, said apparatus comprising:
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a light source for generating a light beam, the light beam being directed along a light path toward the open atmosphere; a first light detector for detecting light from the light beam which is retro-reflected along the light path due to atmospheric elements in the open atmosphere, and for producing a first detection signal; a second light detector for detecting light from the light beam which is forward scattered due to objects which are in the open atmosphere and within the light path, and for producing a second detection signal; and computing means for measuring visibility and present weather based upon the first and second detection signals, wherein said computing means computes a propagation delay between the generated light beam and the retro-reflected light detected by said first light detector, the propagation delay being used by said computing means to measure the present weather. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification