METHOD FOR DETERMINING TRIAXIAL SPACECRAFT ORIENTATION

摘要

The invention relates to the field of space technology. A method for determining a triaxial spacecraft orientation consists in that after angular rate bleedoff the half of the growth of the vector of infinitesimal rotation per cycle is calculated. Then it is determined the quaternion of rotation per cycle followed by determination of triaxial orientation of a spacecraft relative to the reference coordinate system in the form of a quaternion of orientation, which is calculated by quaternion multiplication of previous value of quaternion of orientation by quaternion of rotation per cycle. In this case the initial value of the quaternion of orientation of a spacecraft is determined by measurements of star trackers and further on even cycles an additional quaternion of rotation in two cycles is calculated. On these even cycles an additional quaternion of orientation is calculated by quaternion multiplication of the previous value of additional quaternion of orientation by additional quaternion of rotation in two cycles. At the same time as the initial value of additional quaternion of orientation the initial value of the quaternion of orientation is taken. Also on even cycles a correction quaternion is calculated as one third of difference quaternion between quaternion of orientation and appropriate additional quaternion of orientation. Then at the even cycles a new value of the quaternion of orientation is determined by adding to the quaternion of orientation a correction quaternion, and additional quaternion of orientation is assigned a new value of quaternion of orientation of a spacecraft. The technical result of the invention is to provide a high-precision determination of triaxial orientation of a spacecraft during a long flight without correction using measurements of star trackers.