| 主权项 |
1. A method for determining an attitude of a star sensor based on a rolling shutter imaging, comprising steps of:
providing a star sensor on a spacecraft, the star sensor including an image sensor, a processor, and memory; obtaining an image with the image sensor, the image having an exposure time tInt, a line readout time trd, an interline integral interval time tri and a frame processing time tFp; storing the image in the memory; S1: creating, with the processor, a line based rolling shutter model from the image, the line based rolling shutter model being an optimized relation among the exposure time tint, the line readout time trd, the interline integral interval time tri and the frame processing time tFp of the image; S2: predicting and extracting, with the processor, locations of M navigation stars comprised in a star map stored in the memory of the star sensor according to the optimized relation among the exposure time tInt, the line readout time trd , the interline integral interval time ri and the frame processing time tFp, in which the location of each navigation star of the M navigation stars is used to determine a line number of the each navigation star in the star sensor; and S3:
updating, with the processor, an attitude matrix and an angular velocity of the star sensor according to the locations of the navigation stars and based on a single star recursion attitude estimation of the rolling shutter imaging whenever a position of one navigation star of the M navigation stars is extracted;applying, with the processor, the attitude matrix of the star sensor to a calculation of the attitude matrix of a next navigation star of the M navigation stars by recursion to obtain a recurring attitude matrix of the star sensor;fusing, with the processor, the location of the next navigation star and the recurring attitude matrix of the star sensor to form an updated attitude matrix and an updated angular velocity of the star sensor; anddetermining, with the processor, a final attitude matrix and a final angular velocity of the spacecraft by transferring the updated the attitude matrix and the updated angular velocity of the star sensor sequentially. |
