초록 ▼

A method of sun search and acquisition is disclosed for a spacecraft (18) which is stabilized in three axes. The method utilizes three axes gyro rate and integrated rate sensing together with three simple slit type sensors (10, 20, 30, 40). The method starts from an arbitrary attitude and from body

A method of sun search and acquisition is disclosed for a spacecraft (18) which is stabilized in three axes. The method utilizes three axes gyro rate and integrated rate sensing together with three simple slit type sensors (10, 20, 30, 40). The method starts from an arbitrary attitude and from body rates up to the limits of the gyro rate sensors and is comprised of a rate nulling step followed by two consecutive simple search procedures. One search procedure is about the pitch axis until alignment of the sun with the roll/pitch plane and the other search procedure is about the yaw axis until alignment of the sun with the roll axis. The sun acquisition culminates in pointing the roll axis of the spacecraft (18) toward the sun. By using slit type sun sensors (10, 20, 30, 40) versus a wide field of view sensor it is easier to find a mounting location on a spacecraft (18) which is free from spurious reflections off other parts of the spacecraft.

대표청구항 ▼

A spacecraft stabilized in three mutually orthogonel x, y and z axes comprising: a spacecraft body; sensing means for detecting sunlight having a pair of sensing planes, a first sensing plane of said pair lying in the xz plane of the spacecraft and a second sensing plane of said pair lying in the xy

A spacecraft stabilized in three mutually orthogonel x, y and z axes comprising: a spacecraft body; sensing means for detecting sunlight having a pair of sensing planes, a first sensing plane of said pair lying in the xz plane of the spacecraft and a second sensing plane of said pair lying in the xy plane of the spacecraft, said sensing planes intersecting at the x axis; control means for controlling the orientation of the spacecraft to orient the x axis toward the sun, said control means including means for rotating said spacecraft about the y axis in one direction at a predetermined scan rate while maintaining rotation about the x and z axes at substantially zero, means for initializing a y axis angular position of a spacecraft relative to the sun line of sight when the sun line of sight is aligned with said second sensing plane, means for porpagating the spacecraft y axis angular position in time relative to the initialized y axis angular position by calculation from a y axis rate measurement means for rotating said spacecraft in the opposite direction about said y axis to return said spacecraft to a position with the sun line of sight aligned with the second sensing plane and for stopping rotation of the spacecraft about the y axis, means for rotating said spacecraft about said z axis in one direction at a predetermined scan rate, means for initializing a z axis angular position of the spacecraft relative to the sun line of sight once the sun line of sight is aligned with said first sensing plane, means for propagating the spacecraft z axis angular position in time relative to the initialized z axis angular position by calculation from a z axis rate measurement, means for rotating the spacecraft in the opposite direction about the z axis to return the spacecraft to a position with the sun line of sight aligned with the first sensing plane and to stop rotation of the spacecraft about the z axis.