基于精密时间的星敏感器绝对姿态基准的建立

根据星敏感器外场试验的实际需要,提出一种用于建立星敏感器参考姿态基准的方法.介绍星敏感器参考姿态基准建立的基本原理;分别求取从赤道惯性坐标系i系到地球坐标系w系的转换矩阵Cw1（依靠原子钟精密计时）、从w系到地理坐标系t系的转换矩阵Ctw、从t系到平台坐标系p系的转换矩阵Cpt,从p系到星敏感器坐标系s系的转换矩阵Csp,从而得到i系到s系的转化矩阵Cs1;根据Csi求取星敏感器的姿态角,作为参考姿态基准;编制求解星敏感器参考姿态基准的电算化程序,并绘制星敏感器3个姿态角的误差曲线,最大误差小于0.25″.仿真结果表明,通过精密时间得到的姿态可以作为星敏感器外场试验的参考姿态基准.

Construction of Attitude Reference Benchmark of Star Sensor Based on Precise Timing

To satisfy the need of outfield tests of star sensors, a method is put forward to construct the ref erence attitude benchmark. Firstly, its basic principle is introduced. Then, all the separate conversion matrixes are deduced, which include the conversion matrix Cw responsible for the transformation from the earth centered inertial frame i to the earthcentered earthfixed frame w according to the time of an atomic clock, the conversion matrix Ctwfrom frame w to the geographic frame t, the conversion matrix Cp, from frame t to the platform frame p, and the matrix C~p from frame p to the star sensors frame s. As a result, the attitude matrix C~of the star sensor relative to the frame i can be obtained using all the three matrixes as the multiplicative factors. Next, the reference attitude angles for star sensor outfield tests can be calcu lated from the transformation matrix Ci from frame i to s. Finally, the computer program is given to solve the reference attitudes, and the error curves are drawn about the three axis attitude angles, whose abso lute maximum error is less than 0.25＂. The simulating results manifest that the method by precise timing to acquire the absolute reference attitude benchmark is feasible for star sensor outfield tests.