摘要 |
Concurrent determinations of errors for application of corrections to sensor data signals from an orbiting space vehicle to reduce or to eliminate the three components of boresight error. To locate more accurately the geographical position of targets detected by the sensors of an orbiting satellite, the pitch, roll, and yaw boresight errors caused by distortions or misalignments in the focal plane of the sensors are compensated for by comparing known position coordinates of an object (such as a star) to the observed position coordinates. The known position coordinates are converted to sensor coordinates by a series of intermediate coordinate conversions, essentially from the celestial frame of reference to an earth-centered frame of reference to a satellite attitude frame of reference to the satellite frame of reference to the sensor frame of reference. The corrections are applied frequently enough to take into account the change of the satellite's position relative to the sun to compensate for the thermal effects, inter alia, causing the boresight error. An optimal estimator increases the accuracy of the results.
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