箭载GPS定位临近地面卫星对流层延迟改正模型  

Tropospheric delay correction model of near ground satellite position using on-board GPS

作　　者：饶爱水[1] 李清梅[1] 胡健[1] 吴关鹏[1] 

机构地区：[1]中国卫星海上测控部,江阴214431

出　　处：《中国惯性技术学报》2015年第5期670-673,共4页Journal of Chinese Inertial Technology

摘　　要：针对经典对流层延迟改正模型无法处理负仰角卫星误差修正的问题,在传统球对称标准大气模型的基础上,采用射线描迹法建立了GPS信号穿透对流层的数学模型,推导了根据对流层折射最低点海拔高度计算对流层延迟改正的计算公式;为求解对流层折射最低点海拔高度,采用最小二乘法求得GPS信号穿透对流层时地心张角与最低点海拔高度之间的线性方程,提出了根据卫星和火箭之间的夹角与地心张角之间的关系进行迭代计算,进而求得最低点海拔高度的方法;最后引入了模型误差因子,评估对流层延迟改正模型的效果。采用火箭飞行试验数据对模型进行验证,结果表明,该模型提供的方法能够消除负仰角卫星大部分对流层延迟,消除的最大延迟可达135 m,消除对流层延迟后的临近地面卫星参与定位计算使最终定位精度提高25 m,计算迭代次数平均10次,尤其适合箭载GPS实时定位。In view that classical tropospheric delay correction model cannot deal with deviation correction of negative elevation angel satellite,the phenomenon when GPS signal penetrate troposphere using radar ray tracing was modeled based on traditional spherical symmetry standard atmosphere model,and the formulas for computing the correction of tropospheric delay was deduced based on the lowest altitude of troposphere reflection. To calculate the lowest altitude of tropospheric refraction,the liner equation between geocentric angel and the lowest altitude when GPS signal penetrate troposphere was obtained by using least square method. Then a method for calculating the lowest altitude was proposed based on iterative computation using the relationship between the angle of satellite-to-rocket and the geocentric angel. Finally the efficiency of tropospheric delay correction model was evaluated by introducing the model＇s error factor. The test data of rocket flight were used to validate the model,and the result proves that the proposed method can eliminate most of the tropospheric delay of up to 135 m,and improve the precision of the near ground satellite position of up to 25 m. This method is especially appropriate to real-time positioning of on-board GPS.

关 键 词：折射指数 折射率 地心张角 射线描迹 大气折射 

分 类 号：V19[航空宇航科学与技术—人机与环境工程]