Systems and methods for the accurate tracking of orbital objects
View Patent ↗The present disclosure achieves accurate tracking of sunlit orbital objects, including small, dim orbital debris, using a ground-based telescope and detector which tracks the orbital object. The angular position of the orbital object relative to background celestial objects is accurately determined over a trajectory, allowing accurate determination of the orbit parameters.
1 . A system for tracking an orbital object, the system comprising:
a ground-based telescope coupled to a tracking gimbal;
a camera coupled to the telescope;
wherein the telescope and the camera are collectively operable for acquiring image frames of a solar illuminated orbital object tracked by the telescope and the camera; and
a memory and a processor coupled to the camera storing instructions executed to determine a location of the orbital object within the camera field vs. time;
wherein the memory and the processor further store instructions executed to compare an observed orientation of celestial background objects in the camera field while the solar illuminated orbital object is tracked by the telescope and the camera with an accurately registered database of true celestial background data;
wherein the memory and the processor further store instructions executed to use the comparison of the observed orientation of the celestial background objects with the true celestial background data to correct the orbital object's determined location vs. time; and
wherein the solar illuminated orbital object moves with respect to the celestial background objects in the camera field and the tracking gimbal of the telescope is locked onto the solar illuminated orbital object and moves with the solar illuminated orbital object in real time.
2 . The system of claim 1 , wherein the camera operates at high enough frame rate to ameliorate streaking of celestial background images.
3 . The system of claim 1 , wherein optical input to the camera is intensity modulated to break up celestial background streaks into a spatial pattern on the camera.
4 . The system of claim 1 , wherein the memory and the processor further store instructions executed to control the tracking gimbal to keep the solar illuminated orbital object in a field of view of the camera.
5 . The system of claim 1 , wherein the memory and the processor further store instructions executed to perform data reduction of orbital object track data by accumulation in time of the image frames, first shifting the image frames a predetermined amount for the orbital object motion and then summing in time.
6 . The system of claim 1 , wherein the memory and the processor further store instructions executed to perform data reduction of celestial background track data by accumulation in time of celestial background objects, first shifting the image frames a predetermined amount for background motion and then summing in time.
7 . The system of claim 1 , wherein the memory and the processor further store instructions executed to perform either or both of:
spatial correlation of the celestial background images with accurately registered database celestial image data via 2-D image correlation; and
extracting center locations of celestial objects, then correlating extracted celestial background object locations with accurately registered database celestial object locations via point cloud image correlation.
8 . The system of claim 1 , wherein the memory and the processor further store instructions executed to determine both offset and image rotation of the celestial objects with respect to an accurately registered celestial object database.
9 . The system of claim 1 , wherein the memory and the processor further store instructions executed to use geometrical inversion to convert the orbital object celestial locations vs. time into orbital parameters of the orbital object.
10 . The system of claim 1 , wherein the system further comprises a laser and detector to measure round-trip time-of-flight of a laser pulse to the orbital object, to determine range vs. time.
11 . The system of claim 10 , wherein the memory and the processor further store instructions executed to use geometrical inversion to convert the orbital object celestial locations and range vs. time into orbital parameters of the orbital object.
12 . A method for tracking an orbital object, the method comprising:
providing a ground-based telescope coupled to a tracking gimbal;
providing a camera coupled to the telescope;
wherein the telescope and the camera are collectively operable for acquiring image frames of a solar illuminated orbital object tracked by the telescope and the camera;
determining a location of the orbital object within a camera field vs. time;
comparing an observed orientation of celestial background objects in the camera field while the solar illuminated orbital object is tracked by the telescope and the camera with an accurately registered database of true celestial background data; and
using the comparison of the observed orientation of the celestial background objects with the true celestial background data to correct the orbital object's determined location vs. time;
wherein the solar illuminated orbital object moves with respect to the celestial background objects in the camera field and the tracking gimbal of the telescope is locked onto the solar illuminated orbital object and moves with the solar illuminated orbital object in real time.
13 . The method of claim 12 , wherein the camera operates at high enough frame rate to ameliorate streaking of the celestial background images.
14 . The method of claim 12 , wherein optical input to the camera is intensity modulated to break up celestial background streaks into a spatial pattern on the camera.
15 . The method of claim 12 , wherein camera data is used to control the tracking gimbal to keep the solar illuminated orbital object in a field of view of the camera.
16 . The method of claim 12 , further comprising performing data reduction of orbital object track data by accumulation in time of the image frames, first shifting the image frames a predetermined amount for the orbital object motion and then summing in time.
17 . The method of claim 12 , further comprising performing data reduction of celestial background track data by accumulation in time of celestial background objects, first shifting the image frames a predetermined amount for background motion and then summing in time.
18 . The method of claim 12 , further comprising performing either or both of:
spatial correlation of the celestial background images with accurately registered database celestial image data via 2-D image correlation; and
extracting center locations of celestial objects, then correlating extracted celestial background object locations with accurately registered database celestial object locations via point cloud image correlation.
19 . The method of claim 12 , further comprising determining both offset and image rotation of the celestial objects with respect to an accurately registered celestial object database.
20 . The method of claim 12 , further comprising using geometrical inversion to convert the orbital object celestial locations vs. time into orbital parameters of the orbital object.
21 . The method of claim 12 , further comprising providing a laser and detector to measure round-trip time-of-flight of a laser pulse to the orbital object, to determine range vs. time.
22 . The method of claim 21 , further comprising using geometrical inversion to convert the orbital object celestial locations and range vs . . . time into orbital parameters of the orbital object.
23 . A non-transitory computer-readable medium comprising instructions stored in a memory and executed by a processor to carry out steps for tracking an orbital object, the steps comprising:
acquiring image frames of a solar illuminated orbital object tracked with a ground-based telescope and a camera;
determining a location of the orbital object within a camera field vs. time;
comparing an observed orientation of celestial background objects in the camera field while the solar illuminated orbital object is tracked by the telescope and the camera with an accurately registered database of true celestial background data; and
using the comparison of the observed orientation of the celestial background objects with the true celestial background data to correct the orbital object's determined location vs. time;
wherein the solar illuminated orbital object moves with respect to the celestial background objects in the camera field and the tracking gimbal of the telescope is locked onto the solar illuminated orbital object and moves with the solar illuminated orbital object in real time.
24 . The non-transitory computer readable medium of claim 23 , the steps further comprising performing either or both of:
data reduction of orbital object track data by accumulation in time of the image frames, first shifting the image frames a predetermined amount for the orbital object motion and then summing in time; and
data reduction of celestial background track data by accumulation in time of celestial background objects, first shifting the image frames a predetermined amount for background motion and then summing in time.
25 . The non-transitory computer readable medium of claim 23 , the steps further comprising performing either or both of:
spatial correlation of the celestial background images with accurately registered database celestial image data via 2-D image correlation; and
extracting center locations of celestial objects, then correlating extracted celestial background object locations with accurately registered database celestial object locations via point cloud image correlation.
26 . The non-transitory computer readable medium of claim 23 , the steps further comprising performing determination of both offset and image rotation of the celestial objects with respect to an accurately registered celestial object database.
27 . The non-transitory computer readable medium of claim 23 , the steps further comprising performing geometrical inversion to convert the orbital object celestial locations vs. time into orbital parameters of the orbital object.
28 . The non-transitory computer readable medium of claim 23 , the steps further comprising determining a range to the orbital object by measuring round-trip time-of-flight of a laser pulse to the orbital object in range vs. time.
29 . The non-transitory computer readable medium of claim 28 , the steps further comprising performing geometrical inversion to convert the orbital object celestial locations and range vs. time into orbital parameters of the orbital object.