IMU辅助X射线脉冲星的深空探测器精确定姿方法及仿真

为满足深空探测器的精确定姿需求,提出了一种惯性测量单元(IMU)辅助的X射线脉冲星定姿方法。该方法用IMU的速率陀螺来估计航天器短时姿态,观测两颗或多颗脉冲星的X射线辐射信号,将拟合得到的观测矢量作为滤波器信息输入,利用这两种测姿手段在时间和空间上的互补特性,提供一种全天候、抗干扰性强的定姿方法。仿真结果表明,相比于EKF,基于UKF的俯仰、横滚和偏航三姿态角的测量精度可提高21.9%、21.1%和31.7%;与仅使用脉冲星或IMU的定姿方法相比,组合定姿方法的俯仰角估计精度分别提高了32.5%和77.6%。

Precision Attitude Determination for Deep-Space Mission

An attitude determination method for a deep-space mission spacecraft is derived and its performance is analyzed.The attitude determination system is composed of inertial measurement units(IMU),an X-ray Pulsar scanner,onboard computers and electronic devices.IMU data is processed to maintain real-time knowledge of spacecraft attitude relative to an inertial reference frame.X-ray pulsar scanner data is processed using unscented Kalman filter(UKF) to estimate and correct the attitude determination errors and the gyro drift compensation errors.The results of two X-ray pulsars availability analysis for deep-space attitude determination mission are presented.Linear covariance analysis techniques are used to evaluate nominal attitude determination performance,the effects of sensor measurement accuracy variations,and the effects of gyros misalignment errors.A semi-physical simulation scheme is devised to verify the integrated attitude determination algorithm based on the data from NASA HEASARC.Results of a nonlinear simulation analysis of attitude determination performance are also shown.Compared to only using pulsars or IMU,the attitude determination accuracy of integrated algorithm is higher,and the performance of processing nonlinear state functions for UKF is superior to EKF.It can satisfy the system requirements of high precision and stabilization.