Sensor shift for remote sensing
Techniques for improving the quality of images captured by a remote sensing overhead platform such as a satellite. Sensor shifting is employed in an open-loop fashion to compensate for relative motion of the remote sensing overhead platform to the Earth. Control signals are generated for the sensor shift mechanism by an orbital motion compensation calculation that uses the predicted ephemeris (including orbit dynamics) and image geometry (overhead platform to target). Optionally, the calculation may use attitude and rate errors that are determined from on-board sensors.
1. A remote sensing overhead platform for imaging an area below the platform, comprising:
a remote sensing overhead platform body;
an image sensor positioned on the remote sensing overhead platform body so that the image sensor can be moved relative to the remote sensing overhead platform body in response to control signals; and
a controller that provides the control signals to the image sensor for movement relative to the remote sensing overhead platform body, wherein the control signals are based on movement of the remote sensing overhead platform body relative to the area below to be imaged, wherein the control signals are calculated from a predicted orbit motion, and wherein the calculation of the control signals fails to utilize each of optical correlation and image analysis.
2. A remote sensing overhead platform as defined in claim 1 , wherein the remote sensing overhead platform is an orbital satellite.
3. A remote sensing overhead platform as defined in claim 1 , wherein the image sensor is movable in a first plane relative to the remote sensing overhead platform body.
4. A remote sensing overhead platform as defined in claim 1 , wherein the image sensor is an area array image sensor having a number of rows of pixels that is at least one-tenth of the number of pixels in each row of pixels.
5. A remote sensing overhead platform as defined in claim 1 , wherein the image sensor captures an image and wherein the control signals are based on the predicted orbital motion and the location of the image relative to the remote sensing overhead platform.
6. A remote sensing overhead platform as defined in claim 1 , wherein the image sensor is an area array image sensor having a number of rows of pixels that is at least one-tenth of the number of pixels in each row of pixels and wherein the image sensor is moved so as to compensate for motion of the remote sensing overhead platform for at least 15 ms.
7. An image sensor system carried by a remote sensing overhead platform for imaging an area below the platform, the image sensor system comprising:
an image sensor positioned on the remote sensing overhead platform body so that the image sensor can be moved relative to the remote sensing overhead platform body in response to control signals; and
a controller that provides the control signals to the image sensor for movement relative to the remote sensing overhead platform body, wherein the control signals are based on movement of the remote sensing overhead platform body relative to the area below to be imaged, wherein the control signals are calculated from a predicted orbit motion of the platform, and wherein the calculation of the control signals fails to utilize each of optical correlation and image analysis.
8. An image sensor system as defined in claim 7 , wherein the image sensor is movable in a first plane relative to the remote sensing overhead platform body.
9. An image sensor system as defined in claim 7 , wherein the image sensor is an area array image sensor having a number of rows of pixels that is at least one-tenth of the number of pixels in each row of pixels.
10. An image sensor system as defined in claim 7 , wherein the image sensor captures an image and wherein the control signals are based on the predicted orbital motion and the location of the image relative to the remote sensing overhead platform.
11. An image sensor system as defined in claim 7 , wherein the image sensor is an area array image sensor having a number of rows of pixels that is at least one-tenth of the number of pixels in each row of pixels and wherein the image sensor is moved so as to compensate for motion of the remote sensing overhead platform for at least 15 ms.
12. A remote sensing overhead platform for imaging an area below the platform, comprising:
a remote sensing overhead platform body;
an image sensor positioned on the remote sensing overhead platform body so that the image sensor can be moved relative to the remote sensing overhead platform body in response to control signals, wherein the image sensor is movable in a first plane relative to the remote sensing overhead platform body, wherein the image sensor is an area array image sensor having a number of rows of pixels that is at least one-tenth of the number of pixels in each row of pixels; and
a controller that provides the control signals to the image sensor for movement relative to the remote sensing overhead platform body, wherein the control signals are based on movement of the remote sensing overhead platform body relative to the area below to be imaged, wherein the control signals are entirely free of being based on each of image correlation and image analysis;
wherein the image sensor captures an image and wherein the control signals are based on predicted orbital motion and the location of the image relative to the remote sensing overhead platform.
13. A remote sensing overhead platform as defined in claim 12 , wherein the image sensor is moved so as to compensate for motion of the remote sensing overhead platform for at least 15 ms.