Satellite tracking with a portable telescope and star camera
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
H04B-010/118
H04B-010/61
G01S-003/786
출원번호
US-0625288
(2017-06-16)
등록번호
US-9991958
(2018-06-05)
발명자
/ 주소
Riesing, Kathleen Michelle
Yoon, Hyosang
Cahoy, Kerri Lynn
출원인 / 주소
Massachusetts Institute of Technology
대리인 / 주소
Cooley LLP
인용정보
피인용 횟수 :
0인용 특허 :
5
초록▼
A portable optical ground station can track a satellite with an amateur telescope mounted on a two-axis gimbal. The telescope is aligned with respect to an inertial, Earth-fixed frame using a wide field of view star camera. Star cameras are accurate to the arcsecond level and have the advantage of p
A portable optical ground station can track a satellite with an amateur telescope mounted on a two-axis gimbal. The telescope is aligned with respect to an inertial, Earth-fixed frame using a wide field of view star camera. Star cameras are accurate to the arcsecond level and have the advantage of providing orientation with a single measurement. Using multiple star sensor measurements at different gimbal angles, it is possible to calculate the alignment of the gimbals in the Earth-fixed frame and the alignment of the star sensor in the gimbal frame. Once the alignment is obtained, satellite tracking can be achieved with a known orbit and precise Earth rotation model, such as the International Earth Rotation and Reference System Service (IERS). This alignment procedure can be carried out in less than one hour, making it practical to move and deploy the portable ground station.
대표청구항▼
1. A method of pointing a telescope mounted on a gimbal at a satellite, the method comprising: acquiring a plurality of star camera images with a star camera affixed to the telescope at respective gimbal positions in a plurality of gimbal positions, each star camera image in the plurality of star ca
1. A method of pointing a telescope mounted on a gimbal at a satellite, the method comprising: acquiring a plurality of star camera images with a star camera affixed to the telescope at respective gimbal positions in a plurality of gimbal positions, each star camera image in the plurality of star camera images being at a different gimbal position in the plurality of gimbal positions;determining an alignment of the gimbal to an Earth-centered reference frame and an alignment of the star camera to the gimbal based on the plurality of star camera images and the plurality of gimbal positions; andpointing the telescope at the satellite based on the alignment of the gimbal to the Earth-centered reference frame, the alignment of the star camera to the gimbal, and an alignment of the telescope to the star camera. 2. The method of claim 1, wherein acquiring the plurality of star camera images comprises rotating the telescope and the star camera to a plurality of azimuth angles and a plurality of altitude angles with the gimbal. 3. The method of claim 1, wherein acquiring the plurality of star camera images occurs within one hour. 4. The method of claim 1, wherein determining the alignment of the gimbal to the Earth-centered reference frame and the alignment of the star camera to the gimbal comprises: determining an alignment of the telescope to the gimbal based on the plurality of gimbal positions. 5. The method of claim 1, further comprising: determining the alignment of the telescope to the star camera. 6. The method of claim 5, where determining the alignment of the telescope to the star camera comprises: acquiring an image with an image sensor in optical communication with an eyepiece of the telescope; andcorrelating the image to at least one star camera image in the plurality of star camera images. 7. The method of claim 1, wherein pointing the telescope at the satellite is at a root-mean-square error of less than 180 arcseconds. 8. The method of claim 1, wherein the star camera has a wider field of view than the telescope. 9. The method of claim 1, further comprising: tracking the satellite with the telescope. 10. The method of claim 9, wherein tracking the satellite with the telescope comprises: estimating a change in azimuth angle and/or altitude angle of the satellite based in part on the alignment of the gimbal to the Earth-centered reference frame and the alignment of the star camera to the gimbal. 11. A ground station for communicating with a satellite, the ground station comprising: a telescope to receive an optical signal from the satellite;a gimbal, supporting the telescope, to rotate the telescope through a plurality of gimbal positions;a star camera, attached to the telescope, to capture a plurality of star camera images, each star camera image in the plurality of star camera image being at a different gimbal position in the plurality of gimbal positions; anda processor, operably coupled to the imager and the star camera, to determine an alignment of the gimbal to an Earth-centered reference frame and an alignment of the star camera to the gimbal based on the plurality of star camera images and the plurality of gimbal positions and to command the gimbal to point the telescope at the satellite based on the alignment of the gimbal to the Earth-centered reference frame, the alignment of the star camera to the gimbal, and an alignment of the telescope to the star camera. 12. The ground station of claim 11, wherein the ground station weighs less than about 50 kilograms. 13. The ground station of claim 11, wherein the telescope has a lens aperture of less than about 1 meter. 14. The ground station of claim 11, wherein the gimbal is a two-axis gimbal. 15. The ground station of claim 11, further comprising: an image sensor, in optical communication with an eyepiece of the telescope, to acquire a plurality of telescope images at respective gimbal positions in the plurality of gimbal positions, each telescope image in the plurality of telescope images being at a different gimbal position in the plurality of gimbal positions. 16. The ground station of claim 15, wherein the processor is configured to compensate for error in pointing the telescope at the satellite based on images from at least one of the star camera or the image sensor. 17. The ground station of claim 15, wherein the star camera has a field of view wider than that of the image sensor. 18. The ground station of claim 11, further comprising: a photodetector, in optical communication with an eyepiece of the telescope, to sense the optical signal from the satellite via the telescope. 19. The ground station of claim 11, further comprising: an encoder, operably coupled to the gimbal, to measure a change in angle of the gimbal about at least one axis.
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이 특허에 인용된 특허 (5)
Massie Norbert A. (San Ramon CA) Oster Yale (Danville CA), High resolution telescope.
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