论文部分内容阅读
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。
Aiming at the problem that the classical tropospheric delay correction model can not handle the satellite elevation error correction, based on the traditional spherical symmetry standard atmospheric model, the mathematical model of GPS signal penetrating troposphere is established by using ray tracing method. According to the problem that the tropospheric refraction lowest point In order to solve the tropospheric refraction lowest point altitude, the least squares method is used to find the linear equation between the geocenter angular angle and the lowest altitude when the GPS signal penetrates the troposphere. Based on the satellite equation And the relationship between the angle between the rocket and the angle of the center of the earth to iteratively calculate, and then find the lowest altitude method; Finally, the model error factor is introduced to assess the effectiveness of the tropospheric delay correction model. The experimental results show that the proposed model can eliminate most tropospheric delay of negative-elevation satellites, and the maximum delay can be up to 135 m. After eliminating the tropospheric delay, the adjacent terrestrial satellites are involved in the final location calculation so that the final Positioning accuracy increased 25 m, the average number of iterations calculated 10 times, especially for GPS navigation with GPS real-time positioning.