Solar radiation sensor
First Claim
1. A sunlight sensor comprising at least two light sensitive detectors and a masking element having a pattern of translucent and opaque areas which are disposed to ensure that for any solar declination and any diurnal solar position at least one detector can be exposed to direct sunlight through a translucent area and at least one detector is shaded from direct sunlight by an opaque area wherein the masking element is such that in use the at least two detectors receive substantially equal amounts of diffuse sunlight.
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Abstract
A radiation sensor with particular application to detection of sunshine has at least two (but typically seven) light sensitive detectors and a masking element. The masking element has a pattern of translucent and opaque areas which are disposed to ensure that at any time at least one detector can be exposed to direct sunlight (if the sun is shining) through a translucent area and at least one detector is shaded from direct sunlight by an opaque area. Signal processing apparatus analyses signals from the detectors, such analysis including a comparison of the signal from the detector exposed to the most light and the signal from the detector exposed to the least light.
41 Citations
32 Claims
- 1. A sunlight sensor comprising at least two light sensitive detectors and a masking element having a pattern of translucent and opaque areas which are disposed to ensure that for any solar declination and any diurnal solar position at least one detector can be exposed to direct sunlight through a translucent area and at least one detector is shaded from direct sunlight by an opaque area wherein the masking element is such that in use the at least two detectors receive substantially equal amounts of diffuse sunlight.
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24. A meteorological monitoring instrument comprising:
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a sensor including at least two light sensitive detectors and a masking element having a pattern of translucent and opaque areas which are disposed to ensure that for any solar declination and any diurnal solar position at least one detector can be exposed to direct sunlight through a translucent area and at least one detector is shaded from direct sunlight by an opaque area, wherein the masking element is such that in use the at least two detectors receive substantially equal amounts of diffuse sunlight; and
a signal processing apparatus for processing signals derived from the detectors and for generating an output indicative of the incidence of sunlight upon the sensor.
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25. A method of distinguishing between sunshine and overcast weather conditions comprising:
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placing a sensor in a position where it is liable to be exposed to sunlight, the sensor including at least two light sensitive detectors and a masking element having a pattern of translucent and opaque areas which are disposed to ensure that for any solar declination and any diurnal solar position at least one detector can be exposed to direct sunlight through a translucent area and at least one detector is shaded from direct sunlight by an opaque area, wherein the masking element is such that in use the at least two detectors receive substantially equal amounts of diffuse sunlight;
assessing signals derived from each of the detectors; and
comparing the signals derived from the detector exposed to the greatest and to the least amount of light.
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26. A radiation sensor comprising at least two radiation sensitive detectors and a masking element having a pattern of areas at least one of which is opaque to the radiation and at least one of which is transparent to the radiation, which areas are disposed to ensure that at least one detector can be exposed to direct radiation through a non-opaque area and at least one detector is shaded from direct radiation by an opaque area irrespective of where a point source of radiation might be positioned within a detection field, and wherein in use the at least two detectors receive substantially equal amounts of indirect radiation.
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27. A sunlight sensor comprising at least two light sensitive detectors and a masking element having a pattern of translucent and opaque areas which are disposed to ensure that for any solar declination and any diurnal solar position at least one detector can be exposed to direct sunlight through a translucent area and at least one detector is shaded from direct sunlight by an opaque area wherein the masking element is such that in use all of the detectors of the sensor receive substantially equal amounts of diffuse sunlight.
- 28. A sunlight sensor comprising at least two light sensitive detectors and a masking element having a pattern of translucent and opaque areas which are disposed to ensure that for any solar declination and any diurnal solar position at least one detector can be exposed to direct sunlight through a translucent area and at least one detector is shaded from direct sunlight by an opaque area wherein the masking element is such that in use all of the detectors of the sensor receive light from substantially all parts of the sky away from the sun.
- 30. A sunlight sensor comprising at least two light sensitive detectors and a masking element having a pattern of translucent and opaque areas which are disposed to ensure that for all solar declinations and all diurnal solar positions at least one detector can be exposed to direct sunlight through a translucent area and at least one detector is shaded from direct sunlight by an opaque area wherein the masking element is such that in use the at least two detectors of the sensor receive substantially equal amounts of diffuse sunlight, wherein opaque areas of the masking element are constituted by an opaque pattern on an at least partly translucent cover of the sensor, said cover comprising a hemispherical dome, and wherein the pattern of translucent and opaque areas of the masking element includes a plurality of opaque areas, at least one of which extends between at least two separate locations at the periphery of the dome so as to partition the rest of the dome surface area outside of said at least one opaque area into at least two further areas, each of which includes a translucent area.
Specification