US3657549A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Two-color horizon sensor
Assignee: National Aeronautics and Space Administration
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Filing: 1970-05-21
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Granted: 1972-04-18
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Expires: 1990-05-21
Abstract
Abstract A radiant energy sensor which may be employed to detect discrete radiant energy wavelength bands from a selected portion of a radiating body such as the horizon. As radiant energy from various portions of the body is detected, the energy is analyzed according to its color characteristics by means of a double monochrometer. A combination lens-prism system is used to refract the radiant energy according to its wavelength. Photo detectors in the double monochrometer respond to two selected wavelength bands of the radiant energy and are connected to a difference amplifier to determine the null output of the two detectors. The null condition is adjusted to correspond with the discrete wavelength bands to be sensed.
Inventors
- 👤 Harold H Seward
- 👤 Mark Gorstein
- 👤 Ian G Mcwilliams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 06:08
CPC Classifications
G; G01; G01S; G01S3/00; G01S3/78; G01S3/782; G01S3/785; G01S3/786; G01S3/7868
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
66 words
Apparatus for sensing discrete radiant energies from a radiating body comprising: sampling means for capturing radiant energy from a selected portion of the radiating body; wavelength dispersive refracting means for separating the captured radiant energy in a detection plane according to the wavelength of the radiant energy; and detecting means at selected locations in the detection plane for sensing the radiation at two selected wavelength bands.
Claim 2
Dependent Claim
66 words
Apparatus for sensing discrete radiant energies from a radiating body comprising: sampling means for capturing radiant energy from a selected portion of the radiating body; wavelength dispersive refracting means for separating the captured radiant energy in a detection plane according to the wavelength of the radiant energy; and detecting means at selected locations in the detection plane for sensing the radiation at two selected wavelength bands.
Claim 3
Dependent Claim
44 words
Apparatus for sensing discrete radiant energies according to claim 1 wherein: the detecting means includes two sensors at separate locations in the detection plane and a differential comparator connected to the output of the sensors to process the difference signal in a signal channel.
Claim 4
Dependent Claim
35 words
Apparatus for sensing discrete radiant energies according to claim 2 wherein: the comparator has a null condition at a preselected ratio of the energies sensed by the sensors at the locations in the detection plane.
Claim 5
Dependent Claim
28 words
AppaRatus according to claim 1 for sensing discrete radiant energies from a body radiating light energy wherein: the sampling means includes an optical lens and an aperture plate.
Claim 6
Dependent Claim
49 words
Apparatus according to claim 4 wherein: the optical lens is an objective lens having a given image plane and optical axis; and the aperture plate is positioned in the image plane of the objective lens with an aperture in the plate centered on the optical axis of the lens.
Claim 7
Dependent Claim
44 words
Apparatus according to claim 1 for sensing discrete energies in the light spectrum wherein: the refracting means includes a dispersyn having a lens portion and a prism portion in a single optical element having the form of a peripheral portion of a convex lens.
Claim 8
Dependent Claim
43 words
Apparatus according to claim 6 wherein: the sampling means includes an optical aperture plate; and the refracting means includes a first dispersyn positioned with the focal plane of the convex lens at the aperture plate, thereby collimating the light beamed from the aperture.
Claim 9
Dependent Claim
33 words
Apparatus according to claim 7 wherein: the refracting means further includes a second dispersyn positioned in the collimated light beam from the first dispersyn and having a focal plane at the detection plane.
Claim 10
Dependent Claim
76 words
Apparatus for sensing a preselected altitude from atmospheric radiation near the horizon comprising: image forming means for generating an optical image of a portion of the horizon color profile in an image plane; wavelength dispersive refracting means for separating the optical image according to the wavelengths in the color profile portion at a detection plane; and detecting means in the detection plane for sensing the ratio of the color intensities at two bands of selected wavelengths.
Claim 11
Dependent Claim
76 words
Apparatus for sensing a preselected altitude from atmospheric radiation near the horizon comprising: image forming means for generating an optical image of a portion of the horizon color profile in an image plane; wavelength dispersive refracting means for separating the optical image according to the wavelengths in the color profile portion at a detection plane; and detecting means in the detection plane for sensing the ratio of the color intensities at two bands of selected wavelengths.
Claim 12
Dependent Claim
23 words
Apparatus according to claim 9 wherein: the detecting means includes photodetectors positioned at locations in the detection plane corresponding to the selected wavelengths.
Claim 13
Dependent Claim
31 words
Apparatus according to claim 10 wherein: two photodetectors are positioned in the detection plane; and the detecting means also includes a comparator having two signal inputs connected to the respective photodetectors.
Claim 14
Dependent Claim
37 words
Apparatus according to claim 10 wherein: the photodetectors are two silicon photodiodes and the one photodiode is positioned at a location in the detection plane corresponding to wavelengths in the band of 430 nanometers to 490 nanometers.
Claim 15
Dependent Claim
30 words
Apparatus according to claim 12 wherein: the other photodiode is positioned at a location in the detection plane corresponding to wavelengths in the band of 340 nanometers to 380 nanometers.
Claim 16
Dependent Claim
45 words
Apparatus according to claim 9 wherein: the refracting means includes two dispersyns, each dispersyn having a convex lens portion and a prism portion, the dispersyns being positioned between the image plane and the detection plane with the refraction angles of the prism portions being additive.
Claim 17
Dependent Claim
37 words
Apparatus according to claim 14 wherein: the dispersyns are positioned between the image plane and the detection plane with the focal planes of the respective lens portions located respectively in the image plane and the detection plane.
Claim 18
Independent Claim
63 words
A method of sensing the ratio of discrete wavelength bands in a portion of a colored field comprising: forming an optical image of the portion of the colored field; wavelength dispersive refracting the light from the optical image to form a refraction pattern of the colors in the field portion; and detecting the intensity of two refraction pattern at the discrete wavelength bands.
Claim 19
Independent Claim
63 words
A method of sensing the ratio of discrete wavelength bands in a portion of a colored field comprising: forming an optical image of the portion of the colored field; wavelength dispersive refracting the light from the optical image to form a refraction pattern of the colors in the field portion; and detecting the intensity of two refraction pattern at the discrete wavelength bands.
Claim 20
Dependent Claim
22 words
The method of sensing according to claim 16 including: comparing the intensities of the refraction pattern detected at the discrete wavelength bands.
Claim 21
Dependent Claim
25 words
The method of sensing according to claim 16 wherein: the step of refracting includes refracting the light from the optical image successively through two prisms.
Claim 22
Dependent Claim
23 words
The method of sensing according to claim 18 wherein: the step oF refracting additionally includes collimating the light passing between the two prisms.
Claim 23
Dependent Claim
27 words
The method of sensing according to claim 18 wherein: the step of refracting additionally includes focussing the light from the optical image after successively refracting the light.
Claim 24
Dependent Claim
28 words
The method of sensing according to claim 16 wherein: the step of forming a single image includes focussing an image of the earth horizon in an aperture plate.
Claim 25
Dependent Claim
32 words
The method of claim 21 for sensing the earth-horizon wherein: the step of detecting includes selecting two discrete wavelength bands from a known combination of wavelength bands in the earth-horizon color profile.
Claim 26
Dependent Claim
29 words
The method of claim 22 for sensing the earth-horizon including: referencing the ratio of the detected intensities with the known combination of the two wavelength bands in the earth-horizon.
Claim 27
Dependent Claim
27 words
The method of claim 22 wherein: the step of selecting includes selecting the known combination from a stable combination of wavelength bands in the earth-horizon color profile.
Claim 28
Dependent Claim
25 words
The method of claim 24 wherein: the step of selecting includes selecting the wavelength bands from the range extending from 340 nanometers to 490 nanometers.
References Cited (Backward Citations)
US986642A
Cited
US1687030A
Cited
US3174045A
Cited
US3229566A
Cited
US3381569A
Cited
US3316412A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-04-18 | 1975-10-18 | 1976-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-18 | 1979-10-18 | 1980-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-18 | 1983-10-18 | 1984-04-18 | $7700.00 | Window Closed / Lapsed |