差分码偏差(Differential Code Bias,DCB)是高精度定位和电离层建模的主要影响因素之一.为探讨Gali-leo系统卫星端DCB改正对双频单点定位的影响,本文推导了Galileo 4 种不同频点无电离层组合卫星端DCB改正公式.选取 4 个MGEX(Multi-GNSS Experiment)测站连续 7d的观测数据进行标准单点定位(Standard Point Positioning,SPP)和精密单点定位(Precise Point Positioning,PPP)实验,分析改正与不改正DCB对Galileo定位性能的影响.结果表明:DCB改正对SPP定位精度和PPP收敛时间均有提升,但对PPP收敛后的定位精度几乎没有影响.其中,E1/E5b和E1/E5(a+b)组合提升较小,SPP精度提升为亚厘米至厘米级,PPP收敛速度提升率约为 2.0%和 5.2%;E1/E6 组合提升较大,SPP精度提升为米级,PPP收敛速度提升率约为 32.3%.E1/E5a、E1/E5b和E1/E5(a+b)组合SPP定位精度和PPP定位性能基本相当,优于E1/E6 组合.
Analysis of the Effect of Galileo Pseudorange Hardware Delay on Dual-Frequency Positioning
Differential code bias(DCB)is one of the main influencing factors for high-precision positioning and ionospheric modeling.In order to explore the effect of satellite DCB correction of Galileo system on dual-frequency positioning,this paper derives the DCB correction formulas for four different frequency ionospheric-free combinations of Galileo.Observations from four MGEX(Multi-GNSS Experiment)stations for seven consecutive days were selected for standard point positioning(SPP)and precise point positioning(PPP)experiments to analyze the effects of corrected and uncorrected DCB on Galileo's positioning performance.The results show that the DCB correction improves both SPP positioning accuracy and PPP convergence time but has almost no effect on the positioning accuracy after PPP convergence.Among them,the E1/E5b and E1/E5(a+b)combinations have smaller improvement,the SPP ac-curacy improvement is sub-centimeter to centimeter level,and the PPP convergence speed improvement rate is about 2.0%and 5.2%,the E1/E6 combination has larger improvement,the SPP accuracy improvement is meter level,and the PPP convergence speed improvement rate is about 32.3%,the E1/E5a,E1/E5b and E1/E5(a+b)combinations SPP positioning accuracy and PPP positioning performance are basically comparable and better than the E1/E6 combination.
Galileo Global Positioning Systempseudorange hardware delaydifferential code biasstandard point positioningpre-cise point positioning
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