positive semi-definiteness meaning in English

半正定性

In order to improve the performance of ekf and ukf , the square soot unscented kalman filter ( sr - ukf ) with multiplicative noise is firstly investigated . considering the satellite nonlinear model , the sr - ukf attitude estimator is derived for gyroless satellite attitude estimation to render the state covariance with positive semi - definiteness and exceptional estimation accuracy
对于姿态估计,采用了rao - blackwellization技术将卫星模型状态向量中的线性状态部分(陀螺偏差)和非线性状态部分(卫星姿态)分开处理,线性部分状态可以由卡尔曼滤波( kf )估计得到,非线性部