GBAS中相位平滑伪距差分修正改进算法

针对卫星导航精度问题,提出一种载波相位平滑伪距差分修正算法的改进方案.通过无码载偏离平滑滤波技术来解决电离层对伪距和载波相位观测值带来的不一致性导致的电离层误差加剧问题.利用信号传播中误差模型预测值、载波信号和码伪距确定滤波器的衰减因子,把接收到的双频载波信号相位值和伪距值线性组合,输入滤波器滤波.同时用卫星修正信息对平滑伪距值中钟差进行修正.仿真结果表明通过该算法能够减少滤波后的信号残差,提高载波相位平滑伪距差分修正值标准差的可用性,减少电离层误差对星基导航精密进近阶段定位精度的影响.

Phase Smoothing Pseudorange Differential Correction Improved Algorithm in GBAS

Aiming at improving the accuracy of satellite navigation， a carrier phase smoothing pseudorange correction algorithm was put forward as an improved scheme. Divergence free smoothing filtering technology was used to solve ionospheric error problem. By using the error model predictive value in signal propagation， the carrier signal and the pseudorange， the attenuation factor was determined. The dual frequency carrier signal phase value and pseudorange value were linearly combined， which was then put into the filter. At the same time， the satellite information was used to correct clock offset on smoothing pseudorange. The simulation results show that the algorithm can reduce the residual of the signal after filtering and improve carrier phase smoothing pseudorange correction value availability of standard deviation， as well as reduce the impact of ionospheric error on the positioning accuracy in the satellite based navigation precision approach stage.