无陀螺下基于修正罗德里格参数的星体姿态确定

Satellite Attitude Determination with Modified Rodrigues Parameters without Gyro

介绍了修正罗德里格参数(MRP),分析比较了姿态表示参数修正罗德里格参数和四元数的算法特点。通过仿真计算,比较了当卫星受一阶马尔柯夫干扰力矩作用和CCD星敏感器为唯一星载角运动传感器时,分别用修正罗德里格参数和四元数作为姿态表示参数,采用UKF(Unscented Kalman Filter)估计卫星航向、姿态及相应角速率的滤波效果。结果表明,用修正罗德里格参数法的姿态解算精度比用四元数法的姿态解算精度高,且计算效率明显优于四元数算法,计算量仅相当于四元数算法的一半,这是由于四元数的规范化条件(即模值为1),在姿态确定中会导致误差协方差阵奇异,而修正罗德里格参数虽然不是全局非奇异的,但是可以通过切换方法解决奇异性问题。

Analyzed and compared both MRP and quaternion algorithms characteristics by simulations. The satellite is equipped with CCD （Charge Coupled Devices） as the sole attitude sensor on board , and was disturbed by the first - order Markov force moment . Both MRP andquaternion algorithms were used to represent attitude, and UKF （Unscented Kalman Filter） was used to estimate the satellite＇s attitude and azimuth angles and angular rates. The computational burden of MRP is only half of currently used quaternion, while has better and less memory consumption, because the quaternion standardization leads to singularity problem, but the MRP singularity problem is addressed by MRP switching.