海洋二号D卫星(HY-2D)是中国第4颗海洋动力环境卫星,为研究HY-2D卫星的多普勒无线电定轨定位系统DORIS(Doppler Orbitography and Radio-positioning Integrated by Satellite)的定轨精度,本文构建了卫星姿态模型,选择2021年6月5—17日D...海洋二号D卫星(HY-2D)是中国第4颗海洋动力环境卫星,为研究HY-2D卫星的多普勒无线电定轨定位系统DORIS(Doppler Orbitography and Radio-positioning Integrated by Satellite)的定轨精度,本文构建了卫星姿态模型,选择2021年6月5—17日DORIS相位测量数据,采用观测值历元间差分和动力学方法进行精密定轨,对定轨结果通过观测值拟合残差、重叠弧段、轨道相互比较和激光检核4种方法评估轨道精度,并对使用姿态模型或姿态数据的2种定轨结果之间差异进行讨论。结果表明:(1)13 d观测值残差RMS均值约为0.355 mm/s,轨道重叠弧段三维差异的RMS<2.0 cm;(2)与法国国家空间研究中心CNES(Centre National D’Etudes Spatiales)的精密轨道相比,使用姿态数据两者在径向R、切向T、法向N方向上差异的均方根误差RMS(Root Mean Square)分别为1.02 cm、2.92 cm和3.11 cm,使用姿态模型两者在径向R、切向T、法向N方向上差异的RMS分别为0.97 cm、2.77 cm和3.15 cm。2种结果接近,表明卫星姿态模型与实测姿态数据符合程度高;(3)用激光检核本文计算的轨道与CNES参考轨道的精度,测距残差的RMS分别为2.38 cm和2.24 cm,两种轨道精度相当。展开更多
The Grass Is Singing, the famous British female writer Doris Lessing’s maiden work, has drawn much critical attention since its publication in 1950. This novel has been studied from many perspectives at home and abro...The Grass Is Singing, the famous British female writer Doris Lessing’s maiden work, has drawn much critical attention since its publication in 1950. This novel has been studied from many perspectives at home and abroad, including feminism, psychoanalysis, postcolonialism, spatial criticism, etc. In recent years, more and more scholars have paid attention to the complicated and diverse narration of this novel, but few scholars have studied its polyphonic features. This paper tries to explore the polyphonic features of this novel from its diverse narration and the subjectivity of the female protagonist Mary Turner by applying Bakhtin’s polyphonic theory.展开更多
文摘The Grass Is Singing, the famous British female writer Doris Lessing’s maiden work, has drawn much critical attention since its publication in 1950. This novel has been studied from many perspectives at home and abroad, including feminism, psychoanalysis, postcolonialism, spatial criticism, etc. In recent years, more and more scholars have paid attention to the complicated and diverse narration of this novel, but few scholars have studied its polyphonic features. This paper tries to explore the polyphonic features of this novel from its diverse narration and the subjectivity of the female protagonist Mary Turner by applying Bakhtin’s polyphonic theory.
