US3752993A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Spacecraft attitude sensor
Assignee: National Aeronautics and Space Administration
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Filing: 1971-02-02
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Granted: 1973-08-14
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Expires: 1991-02-02
Abstract
Abstract A system for sensing the attitude of a spacecraft includes a pair of optical scanners having a relatively narrow field of view rotating about the spacecraft x-y plane. The spacecraft rotates about its z axis at a relatively high angular velocity while one scanner rotates at low velocity, whereby a panoramic sweep of the entire celestial sphere is derived from the scanner. In the alternative, the scanner rotates at a relatively high angular velocity about the x-y plane while the spacecraft rotates at an extremely low rate or at zero angular velocity relative to its z axis to provide a rotating horizon scan. To avoid ambiguity while the spacecraft is spinning at an extremely low velocity or is stationary relative to its z axis, the scanners are successively activated during alternate scans. The positions of the scanners about the x-y plane are read out to assist in a determination of attitude. While the satellite is spinning at a relatively high angular velocity, the angular positions of the bodies detected by the scanners are determined relative to the sun by providing a sun detector having a field of view different from the scanners.
Inventors
- 👤 A Davidson
- 👤 M Mclean
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 02:16
CPC Classifications
G; G01; G01S; G01S3/00; G01S3/78; G01S3/782; G01S3/785; G01S3/786; G01S3/7861; G01S3/7862; B; B64; B64G; B64G1/00; B64G1/22; B64G1/24; B64G1/244; B64G1/34; B64G1/36
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
70 words
In an attitude sensing system for a spacecraft having a z axis about which the spacecraft is adapted to spin for stabilization, said z axis being at right angles to an x-y plane of the spacecraft, a first radiant energy detector means having a first relatively narrow field of view and first means for rotating the first field of view about a first axis contained in said spacecraft x-y plane.
Claim 2
Dependent Claim
70 words
In an attitude sensing system for a spacecraft having a z axis about which the spacecraft is adapted to spin for stabilization, said z axis being at right angles to an x-y plane of the spacecraft, a first radiant energy detector means having a first relatively narrow field of view and first means for rotating the first field of view about a first axis contained in said spacecraft x-y plane.
Claim 3
Dependent Claim
35 words
The system of claim 1 further including means responsive to the first detector means for inhibiting rotation of the field of view about the first axis while a target is detected by the detector means.
Claim 4
Dependent Claim
50 words
The system of claim 1 further including means for monitoring the angular position of the first field of view about the spacecraft x-y plane, and means for monitoring the angular position about the z axis of the first field of view when a target is detected by the detector means.
Claim 5
Dependent Claim
32 words
The system of claim 1 further including means for monitoring the angular position about the z axis of the first field of view when a target is detected by the detector means.
Claim 6
Dependent Claim
44 words
The system of claim 4 wherein said monitoring means includes a reference body detector fixedly mounted on the spacecraft, and means for measuring the time displacement between detection of a reference body by the reference body detector and target by the first detector means.
Claim 7
Dependent Claim
23 words
The system of claim 5 further including means for measuring the length Of time a target is detected by the first detector means.
Claim 8
Dependent Claim
43 words
The system of claim 5 further including means responsive to simultaneous detection of a reference body and a target for signalling the simultaneous detection, and means responsive to signalling of the simultaneous detection for altering the normal operation of the time measuring means.
Claim 9
Dependent Claim
35 words
The system of claim 7 wherein the first rotating means includes means for stepping the spacecraft about the x-y plane in response to detection of the reference body except when the simultaneous detection is signalled.
Claim 10
Dependent Claim
42 words
The system of claim 4 additionally comprising: a second radiant energy detector means having a relatively narrow field of view; and second means for rotating said second field of view about a second axis which is substantially parallel to said x-y plane.
Claim 11
Dependent Claim
19 words
The system of claim 4 wherein said first means for rotating, rotates said first field of view through 360*.
Claim 12
Dependent Claim
30 words
The system of claim 9 wherein said first and second means for rotating are responsive to additional means for causing alternate rotations of said first and second fields of view.
Claim 13
Dependent Claim
19 words
The system of claim 11 wherein said first and second fields of view are alternately rotated through 360 degrees.
Claim 14
Dependent Claim
43 words
The system of claim 10 further including means for substantially periodically deriving a spin reference pulse, and means for measuring the time interval between the occurrence time of the reference pulse and detection of a target by the first radiant energy detector means.
Claim 15
Dependent Claim
20 words
The system of claim 13 wherein the means for deriving the reference pulse includes a periodic time reference waveform source.
Claim 16
Dependent Claim
31 words
The system of claim 13 wherein the means for deriving the reference pulse includes a reference body detecting means having a field of view fixed relative to said axis and plane.
Claim 17
Dependent Claim
30 words
The system of claim 15 wherein the field of view of the reference body detecting means is different from the field of view of the first radiant energy detector means.
Claim 18
Dependent Claim
21 words
The system of claim 13 wherein the first field of view is rotated in steps in response to the reference pulse.
Claim 19
Dependent Claim
25 words
The system of claim 17 further including means for inhibiting rotation of the first field of view while a target is detected by the detector.
Claim 20
Dependent Claim
24 words
The system of claim 13 further including means for monitoring the angular position of the first field of view relative to the x-y plane.
Claim 21
Independent Claim
110 words
A method of scanning the celestial sphere with a detector having a relatively narrow field of view, said detector being located on a spacecraft having a z axis about which the spacecraft is adapted to spin for stabilization and an x-y plane at right angles to the z axis, said field of view being rotatable about a first axis substantially contained in the x-y plane, comprising the steps of rotating the spacecraft at a relatively high angular velocity about the z axis while rotating the field of view at a relatively low angular velocity about the first axis, whereby a spiral scan of the sphere is derived from the detector.
Claim 22
Independent Claim
110 words
A method of scanning the celestial sphere with a detector having a relatively narrow field of view, said detector being located on a spacecraft having a z axis about which the spacecraft is adapted to spin for stabilization and an x-y plane at right angles to the z axis, said field of view being rotatable about a first axis substantially contained in the x-y plane, comprising the steps of rotating the spacecraft at a relatively high angular velocity about the z axis while rotating the field of view at a relatively low angular velocity about the first axis, whereby a spiral scan of the sphere is derived from the detector.
Claim 23
Dependent Claim
39 words
The method of claim 20 wherein the field of view is rotated about the first axis through an arc substantially equal to the width of the field of view for each complete revolution of the spacecraft about the axis.
Claim 24
Dependent Claim
29 words
The method of claim 20 further including the step of inhibiting rotation of the field of view about the first axis while a target is detected by the detector.
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) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |