摘要
针对现有基于地磁/加速度计的姿态估计算法存在状态误差协方差阵的奇异值和需要准确已知当地地磁矢量的问题,提出了一种新的姿态估计基本方法。该方法采用修正罗德里格参数(MRPs)表示系统动态,消除了采用四元数法导致的状态误差协方差阵的奇异值问题;根据地磁场缓变的特性,将地磁矢量作为平稳过程加入到状态变量中,使得姿态估计不再需要准确已知当地地磁矢量。针对大初始误差和有色噪声对基本方法的影响,通过引入模型误差预测(NPF)和无迹粒子滤波(UPF)方法对其进行改进,提出了基于模型预测无迹粒子滤波(NP-UPF)的地磁/加速度计的姿态估计新方法。仿真结果表明,NPUPF方法可在大初始误差和非高斯条件下实现高精度的姿态估计,提高了基于地磁/加速度计的姿态估计方法的可靠性和实用性。
Aiming at the problem of existing attitude estimation algorithms based on geomagnetic and accelerometer measurements,that there are shortages on covariance matrix＇s singularity and exactly known local geomagnetic vector,a new basic attitude estimation algorithm is proposed.This algorithm uses Modified Rodrigues Parameters（MRPs） to express the dynamics of system,so that the singularity of covariance matrix owing to quaternion＇s redundancy in expression of system＇s dynamics is eliminated,and the geomagnetic vector as a stationary process is put into the estate variables because of its slowly varying character,so that the problem of exactly known local geomagnetic vector is solved.In allusion to the performance degradation of attitude estimation method based on MRP and Unscented Particle Filter（UPF） when there are large model error and colored noise,an improved scheme for attitude estimation based on Nonlinear Predictive Unscented Particle Filter（NPUPF） is proposed.Simulation results verify that the method improves the robustness and environmental adaptability of attitude estimation algorithm under the condition of system with large model error and colored noise.
出处
《宇航学报》
EI
CAS
CSCD
北大核心
2011年第2期336-342,共7页
Journal of Astronautics
关键词
姿态估计
修正罗德里格参数
地磁
模型误差预测
无迹粒子滤波
模型预测无迹粒子滤波
Attitude estimation
Modified rodrigues parameters（MRPs）
Geomagnetic field
Nonlinear predictive filter（NPF）
Unscented particle filter（UPF）
Nonlinear predictive unscented particle filter（NPUPF）
