초록 ▼

A system for achieving spacecraft camera (1, 2) image registration comprises a portion external to the spacecraft and an image motion compensation system (IMCS) portion onboard the spacecraft. Within the IMCS, a computer (38) calculates an image registration compensation signal (60) which is sent to

A system for achieving spacecraft camera (1, 2) image registration comprises a portion external to the spacecraft and an image motion compensation system (IMCS) portion onboard the spacecraft. Within the IMCS, a computer (38) calculates an image registration compensation signal (60) which is sent to the scan control loops (84, 88, 94, 98) of the onboard cameras (1, 2). At the location external to the spacecraft, the long-term orbital and attitude perturbations on the spacecraft are modeled. Coefficients (K, A) from this model are periodically sent to the onboard computer (38) by means of a command unit (39). The coefficients (K, A) take into account observations of stars and landmarks made by the spacecraft cameras (1, 2) themselves. The computer (38) takes as inputs the updated coefficients (K, A) plus synchronization information indicating the mirror position (AZ, EL) of each of the spacecraft cameras (1, 2), operating mode, and starting and stopping status of the scan lines generated by these cameras (1, 2), and generates in response thereto the image registration compensation signal (60). The sources of periodic thermal errors on the spacecraft are discussed. The system is checked by calculating “measurement residuals”, the difference between the landmark and star locations predicted at the external location and the landmark and star locations as measured by the spacecraft cameras (1, 2).

대표청구항 ▼

Apparatus for limiting the error, to within a preselected limit, in the angular separation of corresponding pixels (with resptect to each other) of repeated images of the same selected imaging area of a spacecraft camera, said apparatus comprising: on board the spacecraft, means for pointing the cam

Apparatus for limiting the error, to within a preselected limit, in the angular separation of corresponding pixels (with resptect to each other) of repeated images of the same selected imaging area of a spacecraft camera, said apparatus comprising: on board the spacecraft, means for pointing the camera towards a scene external to the spacecraft; at a location external to the spacecraft, means for determining long-term motion perturbations on the orbit and attitude of the spacecraft; and coupled to said determining means, means for periodically communicating to a computer on board the spacecraft a representation of said long-term motion perturbations; whereby the computer generates an image registration compensation signal in response to said representation, and sends said compensation signal to the pointing means.