Star tracker with steerable field-of-view baffle coupled to wide field-of-view camera
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
G01C-021/02
H04N-005/225
B64G-001/36
출원번호
US-0893987
(2013-05-14)
등록번호
US-9544488
(2017-01-10)
발명자
/ 주소
Dawson, Robin Mark Adrian
Laine, Juha Pekka
Chaparala, Murali
출원인 / 주소
The Charles Stark Draper Laboratory, Inc.
대리인 / 주소
Sunstein Kann Murphy & Timbers LLP
인용정보
피인용 횟수 :
0인용 특허 :
3
초록▼
A star tracker has an electronically steerable point of view, without requiring a precision aiming mechanism. The star tracker can be strapped down, thereby avoiding problems associated with precision aiming of mechanical devices. The star tracker images selectable narrow portions of a scene, such a
A star tracker has an electronically steerable point of view, without requiring a precision aiming mechanism. The star tracker can be strapped down, thereby avoiding problems associated with precision aiming of mechanical devices. The star tracker images selectable narrow portions of a scene, such as the sky. Each stellar sighting can image a different portion of the sky, depending on which navigational star or group of navigational stars is of interest. The selectability of the portion of the sky imaged enables the star tracker to avoid unwanted light, such as from the sun.
대표청구항▼
1. A star tracker, comprising: a camera having a field of view; andan electronically adjustable baffle assembly disposed relative to the camera and configured to expose a selectable portion, less than all, of the camera field of view to a scene, wherein direction of the selectable portion of the fie
1. A star tracker, comprising: a camera having a field of view; andan electronically adjustable baffle assembly disposed relative to the camera and configured to expose a selectable portion, less than all, of the camera field of view to a scene, wherein direction of the selectable portion of the field of view, relative to the star tracker, is electronically selectable in both azimuth and elevation, and wherein the baffle assembly comprises at least a portion of a dome, the dome defining an aperture configured to expose the selectable portion of the camera field of view to the scene, the baffle assembly being rotatable about an optical axis of the camera. 2. A star tracker according to claim 1, wherein the selectable portion of the camera field of view is circular. 3. A star tracker according to claim 1, wherein the camera field of view is greater than 10°. 4. A star tracker according to claim 1, wherein the selectable portion of the camera field of view comprises less than 30% of the camera field of view. 5. A star tracker according to claim 1, wherein the dome defines an aperture configured to define the selectable portion of the camera field of view exposed to the scene. 6. A star tracker according to claim 1, wherein the aperture is positionable along an arc that intersects, and is coplanar with, the optical axis of the camera. 7. A star tracker according to claim 1, wherein the aperture is positionable within the camera field of view. 8. A star tracker according to claim 6, wherein the baffle assembly comprises a baffle having an axis that coincides with an optical axis of the selectable portion of the camera field of view. 9. A star tracker according to claim 1, wherein the selectable portion of the field of view of the camera comprises at least two discontiguous regions of the field of view of the camera. 10. A star tracker according to claim 1, wherein size of the selectable portion of the field of view of the camera is electronically adjustable. 11. A star tracker according to claim 1, wherein the camera comprises a monocentric objective lens. 12. A star tracker according to claim 11, wherein the camera comprises a plurality of pixelated image sensor arrays and a plurality of optical fibers optically coupling each pixelated image sensor array of the plurality of pixelated image sensor arrays to the monocentric objective lens. 13. A star tracker according to claim 1, further comprising: a first rate sensor having a first sensory axis and being mechanically coupled to the camera;a second rate sensor having a second sensory axis perpendicular to the first sensory axis and being mechanically coupled to the camera; anda controller coupled to the camera, the baffle, the first rate sensor and the second rate sensor and configured to: measure vibration of the camera, based on input signals from the first rate sensor and the second rate sensor; andprocess an image captured by the camera, based on the vibration. 14. A star tracker according to claim 1, further comprising a controller coupled to the camera and the baffle assembly and configured to: cause the camera to capture a first image; thenadjust the baffle assembly, such that a different portion of the camera field of view is exposed to the scene; and thencause the camera to capture a second image. 15. A star tracker according to claim 14, wherein the controller is configured to determine a location of the camera, based at least in part on an analysis of at least a portion of the first image and at least a portion of the second image. 16. A star tracker according to claim 1, further comprising a controller coupled to the camera and the baffle assembly and configured to: adjust the baffle assembly, such that the selectable portion of the camera field of view includes a portion of the scene expected to include a space object having a predictable location;cause the camera to capture an image; anddetermine a location of the camera, based at least in part on information about the space object and an analysis of at least a portion of the image. 17. A star tracker according to claim 16, wherein the space object comprises an astronomical object. 18. A star tracker according to claim 16, wherein the space object comprises an artificial satellite. 19. A star tracker according to claim 16, wherein the controller is configured to determine the location of the camera based at least in part on dispersion of light from the space object through earth's atmospheric limb. 20. A star tracker according to claim 16, wherein the controller is configured to determine the location of the camera based at least in part on refraction of light from the space object through earth's atmospheric limb. 21. A star tracker according to claim 1, further comprising a controller coupled to the camera and the baffle assembly and configured to: cause the camera to capture an image; andanalyze a portion, less than all, of the image, the portion of the image corresponding to the portion of the camera field of view exposed to the scene. 22. A star tracker according to claim 1, wherein: the camera comprises a plurality of image sensor arrays, each image sensor array of the plurality of image sensor arrays comprising a plurality of pixels; and further comprising:a controller coupled to the camera and the baffle assembly and configured to read a subset, less than all, of the pixels of the plurality of image sensor arrays, the subset corresponding to the selectable portion of the camera field of view exposed to the scene. 23. A method for exposing a selectable portion, less than all, of a field of view of a camera in a star tracker to a scene, the method comprising: disposing a baffle assembly adjacent the camera, such that the camera is aimed toward an interior of the baffle assembly, the baffle assembly being configured to define an aperture whose position on the baffle assembly is electronically adjustable, in both azimuth and elevation, and such that the aperture defines the selectable portion, less than all, of the field of view of the camera exposed to the scene, and wherein the baffle assembly comprises at least a portion of a dome, the dome defining an aperture configured to expose the selectable portion of the camera field of view to the scene, the baffle assembly being rotatable about an optical axis of the camera; andunder control of a processor, adjusting the position of the aperture on the baffle assembly, such that the aperture is oriented toward the scene. 24. A method according to claim 23, wherein: the baffle assembly comprises a dome that defines an elongated opening extending along a longitude of the dome; the method further comprising:disposing a curtain within the opening, the curtain being movable along the longitude of the dome, the curtain obscuring the opening from the camera field of view, except the curtain defining the aperture; wherein adjusting the position of the aperture comprises: under control of a processor, rotating the dome about an axis of symmetry of the dome, such that the opening in the dome is oriented toward the scene; andunder control of a processor, moving the curtain along the longitude of the dome, such that the aperture is oriented toward the scene. 25. A method according to claim 23, further comprising: under control of a processor, measuring vibration of the camera, based on input signals from a first rate sensor and a second rate sensor; andprocessing an image captured by the camera, based on the vibration. 26. A method according to claim 23, further comprising: after adjusting the position of the aperture, under control of a processor, capturing a first image by the camera; thenadjusting the position of the aperture on the baffle assembly, such that a different portion of the camera field of view is exposed to the scene; and thenunder control of the processor, capturing a second image by the camera. 27. A method according to claim 26, further comprising determining a location of the camera, based at least in part on an analysis of at least a portion of the first image and at least a portion of the second image. 28. A method according to claim 23, wherein: adjusting the position of the aperture comprises automatically adjusting the position of the aperture such that the selectable portion of the camera field of view includes a portion of the scene expected to include a space object having a predictable location;causing the camera to capture an image; andautomatically determining a location of the camera, based at least in part on information about the space object and an analysis of at least a portion of the image. 29. A method according to claim 28, wherein the space object comprises an astronomical object. 30. A method according to claim 28, wherein the space object comprises an artificial satellite. 31. A method according to claim 28, wherein determining the location of the camera comprises determining the location of the camera based at least in part on dispersion of light from the space object through earth's atmospheric limb. 32. A method according to claim 28, wherein determining the location of the camera comprises determining the location of the camera based at least in part on refraction of light from the space object through earth's atmospheric limb. 33. A method according to claim 23, further comprising: automatically causing the camera to capture an image; andautomatically analyzing a portion, less than all, of the image, the portion of the image corresponding to the portion of the camera field of view exposed to the scene. 34. A method according to claim 23, wherein: the camera comprises a plurality of image sensor arrays, each image sensor array of the plurality of image sensor arrays comprising a plurality of pixels; the method further comprising:reading a subset, less than all, of the pixels of the plurality of image sensor arrays, the subset corresponding to the selectable portion of the camera field of view exposed to the scene. 35. A computer program product for exposing a selectable portion, less than all, of a field of view of a camera in a star tracker to a scene, wherein a baffle assembly is disposed adjacent the camera, such that the camera is aimed toward an interior of the baffle assembly, the baffle assembly being configured to define an aperture whose position on the baffle assembly is electronically adjustable, both in azimuth and elevation, and such that the aperture defines the selectable portion, less than all, of the field of view of the camera exposed to the scene, and wherein the baffle assembly comprises at least a portion of a dome, the dome defining an aperture configured to expose the selectable portion of the camera field of view to the scene, the baffle assembly being rotatable about an optical axis of the camera, the computer program product comprising a non-transitory computer-readable medium having computer readable program code stored thereon, the computer readable program code being configured to cause the processor to perform operations including: adjusting the position of the aperture on the baffle assembly, such that the aperture is oriented toward the scene. 36. A computer program product according to claim 35, wherein the baffle assembly comprises a dome that defines an elongated opening extending along a longitude of the dome, a curtain is disposed within the opening, the curtain being movable along the longitude of the dome, the curtain obscuring the opening from the camera field of view, except the curtain defining the aperture and the computer readable program code is configured to adjust the position of the aperture by causing the processor to perform operations including: rotating the dome about an axis of symmetry of the dome, such that the opening in the dome is oriented toward the scene; andmoving the curtain along the longitude of the dome, such that the aperture is oriented toward the scene. 37. A star tracker according to claim 2, wherein size of the selectable portion of the field of view of the camera is electronically adjustable. 38. A star tracker, comprising: a camera having a field of view; andan electronically adjustable baffle assembly disposed relative to the camera and configured to expose a selectable portion, less than all, of the camera field of view to a scene, wherein direction of the selectable portion of the field of view, relative to the star tracker, is electronically selectable in both azimuth and elevation, wherein the baffle assembly comprises a plurality of elements, wherein transparency of each element of the plurality of elements is electronically controllable, such that the selectable portion of the field of view of the camera is exposed to the scene through at least one transparent element of the plurality of elements and a remaining portion of the field of view of the camera is obscured from the scene by at least one non-transparent element of the plurality of the elements. 39. A star tracker according to claim 38, wherein the selectable portion of the camera field of view is circular. 40. A star tracker according to claim 38, wherein the camera field of view is greater than 10°. 41. A star tracker according to claim 38, wherein the selectable portion of the camera field of view comprises less than 30% of the camera field of view. 42. A star tracker according to claim 38, wherein the baffle defines an aperture configured to define the selectable portion of the camera field of view exposed to the scene. 43. A star tracker according to claim 38, wherein the aperture is positionable along an arc that intersects, and is coplanar with, the optical axis of the camera. 44. A star tracker according to claim 38, wherein the aperture is positionable within the camera field of view. 45. A star tracker according to claim 38, wherein the selectable portion of the field of view of the camera comprises at least two discontiguous regions of the field of view of the camera. 46. A star tracker according to claim 38, wherein size of the selectable portion of the field of view of the camera is electronically adjustable. 47. A star tracker according to claim 38, wherein the camera comprises a monocentric objective lens. 48. A star tracker according to claim 47, wherein the camera comprises a plurality of pixelated image sensor arrays and a plurality of optical fibers optically coupling each pixelated image sensor array of the plurality of pixelated image sensor arrays to the monocentric objective lens. 49. A star tracker according to claim 38, further comprising: a first rate sensor having a first sensory axis and being mechanically coupled to the camera;a second rate sensor having a second sensory axis perpendicular to the first sensory axis and being mechanically coupled to the camera; anda controller coupled to the camera, the baffle, the first rate sensor and the second rate sensor and configured to: measure vibration of the camera, based on input signals from the first rate sensor and the second rate sensor; andprocess an image captured by the camera, based on the vibration. 50. A star tracker according to claim 38, further comprising a controller coupled to the camera and the baffle assembly and configured to: cause the camera to capture a first image; thenadjust the baffle assembly, such that a different portion of the camera field of view is exposed to the scene; and thencause the camera to capture a second image. 51. A star tracker according to claim 50, wherein the controller is configured to determine a location of the camera, based at least in part on an analysis of at least a portion of the first image and at least a portion of the second image. 52. A star tracker according to claim 38, further comprising a controller coupled to the camera and the baffle assembly and configured to: adjust the baffle assembly, such that the selectable portion of the camera field of view includes a portion of the scene expected to include a space object having a predictable location;cause the camera to capture an image; anddetermine a location of the camera, based at least in part on information about the space object and an analysis of at least a portion of the image. 53. A star tracker according to claim 52, wherein the space object comprises an astronomical object. 54. A star tracker according to claim 52, wherein the space object comprises an artificial satellite. 55. A star tracker according to claim 52, wherein the controller is configured to determine the location of the camera based at least in part on dispersion of light from the space object through earth's atmospheric limb. 56. A star tracker according to claim 52, wherein the controller is configured to determine the location of the camera based at least in part on refraction of light from the space object through earth's atmospheric limb. 57. A star tracker according to claim 38, further comprising a controller coupled to the camera and the baffle assembly and configured to: cause the camera to capture an image; andanalyze a portion, less than all, of the image, the portion of the image corresponding to the portion of the camera field of view exposed to the scene. 58. A star tracker according to claim 38, wherein: the camera comprises a plurality of image sensor arrays, each image sensor array of the plurality of image sensor arrays comprising a plurality of pixels; and further comprising:a controller coupled to the camera and the baffle assembly and configured to read a subset, less than all, of the pixels of the plurality of image sensor arrays, the subset corresponding to the selectable portion of the camera field of view exposed to the scene. 59. A method for exposing a selectable portion, less than all, of a field of view of a camera in a star tracker to a scene, the method comprising: disposing a baffle assembly adjacent the camera, such that the camera is aimed toward an interior of the baffle assembly, the baffle assembly being configured to define an aperture whose position on the baffle assembly is electronically adjustable, in both azimuth and elevation, and such that the aperture defines the selectable portion, less than all, of the field of view of the camera exposed to the scene, and the baffle assembly comprises a plurality of elements, wherein transparency of each element of the plurality of elements is electronically controllable; andunder control of a processor, adjusting the position of the aperture on the baffle assembly, such that the aperture is oriented toward the scene, including, under control of a processor, setting transparency of at least one selected element of the plurality of elements, such that the selectable portion of the field of view of the camera is exposed to the scene through at least one transparent element of the plurality of elements and a remaining portion of the field of view of the camera is obscured from the scene by at least one non-transparent element of the plurality of the elements. 60. A method according to claim 59, wherein adjusting the position of the aperture on the baffle assembly comprises, under control of the processor, setting transparency of the at least one selected element of the plurality of elements to adjust size of the aperture. 61. A method according to claim 59, further comprising: under control of a processor, measuring vibration of the camera, based on input signals from a first rate sensor and a second rate sensor; andprocessing an image captured by the camera, based on the vibration. 62. A method according to claim 59, further comprising: after adjusting the position of the aperture, under control of a processor, capturing a first image by the camera; thenadjusting the position of the aperture on the baffle assembly, such that a different portion of the camera field of view is exposed to the scene; and thenunder control of the processor, capturing a second image by the camera. 63. A method according to claim 62, further comprising determining a location of the camera, based at least in part on an analysis of at least a portion of the first image and at least a portion of the second image. 64. A method according to claim 59, wherein: adjusting the position of the aperture comprises automatically adjusting the position of the aperture such that the selectable portion of the camera field of view includes a portion of the scene expected to include a space object having a predictable location;causing the camera to capture an image; andautomatically determining a location of the camera, based at least in part on information about the space object and an analysis of at least a portion of the image. 65. A method according to claim 64, wherein the space object comprises an astronomical object. 66. A method according to claim 64, wherein the space object comprises an artificial satellite. 67. A method according to claim 64, wherein determining the location of the camera comprises determining the location of the camera based at least in part on dispersion of light from the space object through earth's atmospheric limb. 68. A method according to claim 64, wherein determining the location of the camera comprises determining the location of the camera based at least in part on refraction of light from the space object through earth's atmospheric limb. 69. A method according to claim 59, further comprising: automatically causing the camera to capture an image; andautomatically analyzing a portion, less than all, of the image, the portion of the image corresponding to the portion of the camera field of view exposed to the scene. 70. A method according to claim 59, wherein: the camera comprises a plurality of image sensor arrays, each image sensor array of the plurality of image sensor arrays comprising a plurality of pixels; the method further comprising:reading a subset, less than all, of the pixels of the plurality of image sensor arrays, the subset corresponding to the selectable portion of the camera field of view exposed to the scene. 71. A computer program product for exposing a selectable portion, less than all, of a field of view of a camera in a star tracker to a scene, wherein a baffle assembly is disposed adjacent the camera, such that the camera is aimed toward an interior of the baffle assembly, the baffle assembly being configured to define an aperture whose position on the baffle assembly is electronically adjustable, both in azimuth and elevation, and such that the aperture defines the selectable portion, less than all, of the field of view of the camera exposed to the scene, and wherein the baffle assembly comprises a plurality of elements, wherein transparency of each element of the plurality of elements is electronically controllable, the computer program product comprising a non-transitory computer-readable medium having computer readable program code stored thereon, the computer readable program code being configured to cause the processor to perform operations including: adjusting the position of the aperture on the baffle assembly, such that the aperture is oriented toward the scene, by setting transparency of at least one selected element of the plurality of elements, such that the selectable portion of the field of view of the camera is exposed to the scene through at least one transparent element of the plurality of elements and a remaining portion of the field of view of the camera is obscured.
연구과제 타임라인
LOADING...
LOADING...
LOADING...
LOADING...
LOADING...
이 특허에 인용된 특허 (3)
Shafer David R. (Fairfield CT), Monocentric optical systems.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.