实时高动态GNSS信号模拟器高精度伪距生成方法

针对伪距实时生成高动态GNSS信号模拟器的关键技术进行了研究,分析了现有真实距离计算方法的问题,提出一种改进的卫星-用户真实距离求解算法.该方法将航迹位置坐标作为用户位置输入,利用开普勒轨道根数计算卫星位置,实现GNSS信号模拟器的星座仿真与参量计算.在伪距计算过程中,为了精确计算真实距离,需要考虑在迭代过程中地固坐标系旋转造成的坐标值变化;在伪距生成过程中,提出一种基于三次样条函数的伪距三阶多项展开式系数的直接计算方法,避免了现存算法需要分别计算卫星、用户位置的高阶导数以及伪距误差的高阶导数等卫星-用户视向动态参数的问题,降低了计算的复杂度.同时也解决了现存算法无法精确计算视向动态参数造成伪距多项式系数计算不精确的问题,提高了伪距生成的精度.仿真结果表明,用该方法计算的伪距精度优于0.1mm.

Method of High Accuracy Pseudorange Generation for Real-time High Dynamic GNSS Signal Simulator

Increasing the accuracy of pseudorange (PR) generation is one of the key technologies in developing real-time high dynamic globol navigation satellite system(GNSS) signal simulator. In this work, the proposed method takes user trajectory coordinates as input, and uses Keplerian parameters to calculate satellite positions for constellation simulation and parameter generation. To achieve high accuracy true range, the coordinate differences due to ECEF rotation should be considered during iterative calculation of PR. For PR generation, a cubic spline based algorithm is proposed to calculate the 3rd order PR polynomial coefficients directly. Above measures avoid the complexity and inaccuracy in existing algorithms which need to calculate satellite-user line-of-sight dynamic parameters such as high order derivatives for PR errors, satellite positions and user position respectively. Simulation result shows that the fitting error of proposed method is below 0.1 mm.