초록 ▼

A method for inertially aligning a spacecraft along an axis, comprising the steps of using quaternion feedback control to reorient the spacecraft, and during the step of reorienting, using rate integrating gyroscopes in a pulse rebalance loop. The method operates to orient the spacecraft along an in

A method for inertially aligning a spacecraft along an axis, comprising the steps of using quaternion feedback control to reorient the spacecraft, and during the step of reorienting, using rate integrating gyroscopes in a pulse rebalance loop. The method operates to orient the spacecraft along an inertial direction of interest by the steps of operating a sensor to provide an initial fix on the inertial direction of interest; repetitively determining a difference between a commanded quaternion and a quaternion estimated based on sensed angular rates; and selectively applying torques to the spacecraft so as to drive the difference towards zero such that a spacecraft vector is aligned with the inertia direction of interest, thereby orienting the spacecraft. One mode of operation maintains the spacecraft fixed in orientation, while another mode of operation rotates the spacecraft about the direction of interest by using a bias-rate blind quaternion propagation technique.

대표청구항 ▼

[ What is claimed is:] [1.] A method for aligning a spacecraft about an axis, comprising the steps of:obtaining a single two-axis inertial reference;obtaining a desired quaternion which represents the desired attitude of the spacecraft;determining an attitude error quaternion representing a differen

[ What is claimed is:] [1.] A method for aligning a spacecraft about an axis, comprising the steps of:obtaining a single two-axis inertial reference;obtaining a desired quaternion which represents the desired attitude of the spacecraft;determining an attitude error quaternion representing a difference between the desired attitude of the spacecraft and a currently estimated attitude of the spacecraft; andrepetitively computing and applying closed loop torques so as to drive the error quaternion towards zero, in conjunction with any non-zero spacecraft body rates, so as to orient the spacecraft in accordance with the single two-axis inertial reference.