US3714432A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Infrared horizon locator
Assignee: National Aeronautics and Space Administration
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Filing: 1971-05-26
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Granted: 1973-01-30
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Expires: 1991-05-26
Abstract
Abstract A precise method and apparatus for locating the earth''s infrared horizon from space that is independent of season and latitude. First and second integrations of the earth''s radiance profile are made from space to earth with the second delayed with respect to the first. The second integration is multiplied by a predetermined constant R and then compared with the first integration. When the two are equal the horizon is located.
Inventors
- 👤 A Jalink
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:51
CPC Classifications
G; G01; G01S; G01S3/00; G01S3/78; G01S3/782; G01S3/785; G01S3/786; G01S3/7868
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
168 words
A method for locating the earth''s horizon from a spacecraft comprising the steps of: providing a first integration of the IR radiance profile of the earth''s horizon from space to earth with the lower limit of said first integration being a point in space where the radiation is approximately zero and with the upper limit of said first integration being continuously changing from space to earth; providing simultaneously with said first integration, a second integration of the IR radiance profile of the earth''s horizon from space to earth, said second integration having the same lower limit as said first integration and having an upper limit that lags the upper limit of said first integration by a prechosen distance Delta h; multiplying said second integration by a predetermined constant R greater than 1; and comparing said first integration with said second integration multiplied by R whereby when the two compared values are equal the upper limit of said first integration is indicative of the location of the earth''s horizon.
Claim 2
Independent Claim
168 words
A method for locating the earth''s horizon from a spacecraft comprising the steps of: providing a first integration of the IR radiance profile of the earth''s horizon from space to earth with the lower limit of said first integration being a point in space where the radiation is approximately zero and with the upper limit of said first integration being continuously changing from space to earth; providing simultaneously with said first integration, a second integration of the IR radiance profile of the earth''s horizon from space to earth, said second integration having the same lower limit as said first integration and having an upper limit that lags the upper limit of said first integration by a prechosen distance Delta h; multiplying said second integration by a predetermined constant R greater than 1; and comparing said first integration with said second integration multiplied by R whereby when the two compared values are equal the upper limit of said first integration is indicative of the location of the earth''s horizon.
Claim 3
Independent Claim
168 words
A method for locating the earth''s horizon from a spacecraft comprising the steps of: providing a first integration of the IR radiance profile of the earth''s horizon from space to earth with the lower limit of said first integration being a point in space where the radiation is approximately zero and with the upper limit of said first integration being continuously changing from space to earth; providing simultaneously with said first integration, a second integration of the IR radiance profile of the earth''s horizon from space to earth, said second integration having the same lower limit as said first integration and having an upper limit that lags the upper limit of said first integration by a prechosen distance Delta h; multiplying said second integration by a predetermined constant R greater than 1; and comparing said first integration with said second integration multiplied by R whereby when the two compared values are equal the upper limit of said first integration is indicative of the location of the earth''s horizon.
Claim 4
Independent Claim
168 words
A method for locating the earth''s horizon from a spacecraft comprising the steps of: providing a first integration of the IR radiance profile of the earth''s horizon from space to earth with the lower limit of said first integration being a point in space where the radiation is approximately zero and with the upper limit of said first integration being continuously changing from space to earth; providing simultaneously with said first integration, a second integration of the IR radiance profile of the earth''s horizon from space to earth, said second integration having the same lower limit as said first integration and having an upper limit that lags the upper limit of said first integration by a prechosen distance Delta h; multiplying said second integration by a predetermined constant R greater than 1; and comparing said first integration with said second integration multiplied by R whereby when the two compared values are equal the upper limit of said first integration is indicative of the location of the earth''s horizon.
Claim 5
Independent Claim
199 words
A device for locating the earth''s IR horizon from space comprising: first integrating means located in space for integrating from space to earth the earth''s IR radiance profile with the lower limit of said first integration being a point in space where the radiation is approximately zero; second integrating means located in space adjacent said first integrating means for integrating from space to earth the earth''s IR radiance profile with the lower limit of said second integration being said point in space where the radiation is approximately zero; said first and second integrating means including means for making the integrations by the twO integrating means simultaneously with the upper limits of the two integrations continuously changing but with the upper limit of the integration by the second integrating means lagging the upper limit of the integration by the first integrating means a prechosen vertical distance Delta h; and means for determining at what point in the integration by said first integrating means that the output of said first integrating means is equal to the output of said second integrating means times a predetermined constant R greater than one whereby said point identifies the location of the earth''s IR horizon.
Claim 6
Independent Claim
199 words
A device for locating the earth''s IR horizon from space comprising: first integrating means located in space for integrating from space to earth the earth''s IR radiance profile with the lower limit of said first integration being a point in space where the radiation is approximately zero; second integrating means located in space adjacent said first integrating means for integrating from space to earth the earth''s IR radiance profile with the lower limit of said second integration being said point in space where the radiation is approximately zero; said first and second integrating means including means for making the integrations by the twO integrating means simultaneously with the upper limits of the two integrations continuously changing but with the upper limit of the integration by the second integrating means lagging the upper limit of the integration by the first integrating means a prechosen vertical distance Delta h; and means for determining at what point in the integration by said first integrating means that the output of said first integrating means is equal to the output of said second integrating means times a predetermined constant R greater than one whereby said point identifies the location of the earth''s IR horizon.
Claim 7
Dependent Claim
56 words
A device for locating the earth''s IR horizon from space according to claim 2 wherein said first and second integrating means includes an optical scanning means having at least two adjacent fields of view with the field of view associated with said first integrating means leading the fields of view associated with said second integrating means.
Claim 8
Dependent Claim
43 words
A device for locating the earth''s IR horizon from space according to claim 3 wherein the end of each scan by said scanning means is such that the trailing edges of all of said fields of view are viewing space at all times.
Claim 9
Dependent Claim
42 words
A device for locating the earth''s IR horizon from space according to claim 4 wherein said fields of view associated with said second integrating means consists of two equal fields of view located on opposite sides of said first field of view.
Claim 10
Dependent Claim
45 words
A device for locating the earth''s IR horizon from space according to claim 5 wherein each of said two equal fields of view located on opposite sides of said first field of view are 1/2 R times as wide as said first field of view.
Claim 11
Dependent Claim
38 words
A device for locating the earth''s IR horizon from space according to claim 6 wherein each of said fields of view includes an opening in a field stop through which radiance is projected by said optical scanning means.
Claim 12
Dependent Claim
48 words
A device for locating the earth''s IR horizon from space according to claim 7 wherein a thermistor flake, that changes resistance in accordance with the radiation that strikes it, is placed back of each of said openings such that it intercepts all radiation that passes through the opening.
Claim 13
Dependent Claim
103 words
A device for locating the earth''s IR horizon from space according to claim 8 wherein the two thermistor flakes located back of said openings corresponding to the fields of view associated with said second integrating means are connected in a bridge circuit opposite a battery having V volts and the thermistor flake located back of said opening corresponding to the field of view associated with said first integrating means is connected in said bridge circuit opposite a battery having RV volts whereby when said bridge becomes balanced the point in the first integration is indicative of the location of the earth''s IR horizon.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-30 | 1976-07-31 | 1977-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-30 | 1980-07-31 | 1981-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-30 | 1984-07-31 | 1985-01-30 | $7700.00 | Window Closed / Lapsed |