基于SOFA的ITRS与ICRS相互转换方法研究

基础天文标准库(SOFA)是国际地球自转服务(IERS)协议提供的关于地球姿态、时间尺度和历法的一系列程序集;国际地球参考系(ITRS)与国际天球参考系(ICRS)是描述自然天体或人造天体在空间的方向或位置,地面站或运动物体在地球上的位置和运动速度的基础参考系统。本文主要介绍了ITRS与ICRS的发展以及基于SOFA的ITRS与ICRS之间不同的转换方法的实现。     

Bangladeshi American Response to the 1998 Status of Forces Agreement (SOFA): An Assessment*

Following the devastating flood in 1998, the U.S. government proposed a Status of Forces Agreement (SOFA) to the Bangladesh government. Accepting the 1998 SOFA would have allowed entry of U.S. troops in Bangladesh without passports or visas and without requiring declaration of military hardware. This would have facilitated American forces support for relief operations and rehabilitation of disaster victims in the shortest possible time. Unfortunately, the Bangladesh government rejected the U.S. terms outlined in the 1998 proposal. A sample survey was conducted among Bangladeshi Americans to examine their opinions regarding the 1998 SOFA. Survey data reveals that slightly over 58 percent of the respondents supported signing the SOFA. Reasons for their support or opposition to the U.S. proposal are also presented. Statistical analyses suggest that whether respondents have studied or are currently studying in the United States emerged as the most significant factor associated with approval or disapproval of the 1998 SOFA. Implications of the study findings are also discussed.     

天体视位置计算研究

利用美国海军天文台提供的矢量程序包和国际天文协会提供的基础天文标准库,研究了在地球和月球上精度可以达到毫角秒的恒星和行星视位置计算,分析了恒星视位置计算中的各种改正影响。     

基于 SOFA 的 GCRS 与 ITRS 间坐标转换

协议天球坐标系GCRS是一个准惯性坐标系,在研究卫星运动状态一般都是在这个坐标系下进行。国际地球参考系ITRS是我们常用的坐标系,一般性测量涉及的坐标都是这个坐标系。为了更方便地研究卫星问题,经常需要在这两个坐标系下进行转换。 IAU的标准基本天文程序库SOFA给出基本天文运算的库函数,利用这些库函数,可以方便地实现这两个坐标系的转换。基于SOFA的这些特点,利用C＋＋对GCRS与ITRS的坐标转换进行了研究。     

基于GCRS-ITRS变换的星下点求解研究

借鉴数值分析的思想,在大地椭球模型的基础上采用IERS2010规范,结合成熟的基本天文标准(SOFA)程序库,在C⁺⁺环境下设计一种基于GCRS-ITRS变换关系的星下点计算方法,以满足其实时性及精确度的要求。