Influence of differential code bias on QZSS single point positioning
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摘要: 为探究差分码偏差(DCB)对准天顶卫星系统(QZSS)伪距单点定位(SPP)的影响,推导了QZSS伪距单点定位时间群延迟(TGD)和DCB改正模型,并选取6个MGEX (Multi-GNSS Experiment) 测站连续7 d的观测数据按照两种不同方案进行实验. 结果表明:DCB产品月稳定度较好,无明显波动,各颗卫星月稳定度优于0.2 ns,与TGD互差值优于2.5 ns;TGD/DCB改正对SPP精度影响为米级,经TGD/DCB改正后水平方定位精度可从4~9 m提升至3~6 m,高程方向可从7~9 m提升至5~7 m,提升率为10%~46%. 可见DCB改正对单点定位精度影响较大,在定位解算中不可忽略.
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关键词:
- 准天顶卫星系统(QZSS) /
- 时间群延迟(TGD) /
- 差分码偏差(DCB) /
- 伪距单点定位(SPP) /
- 定位精度
Abstract: To investigate the effect of differential code bias on Quasi-Zenith Satellite System(QZSS) pseudorange single-point positioning, this paper derives a differential code bias(DCB) and timing group delay(TGD) correction model for QZSS pseudorange single-point positioning, and selects 6 Multi-GNSS Experiment(MGEX) stations for 7 day of continuous observation data to conduct experiments according to two different schemes. The results show that the monthly stability of DCB products is good without obvious fluctuations, and the monthly stability of each satellite is better than 0.2 ns, and the mutual difference value with TGD is better than 2.5 ns. The impact of TGD/DCB correction on SPP accuracy is of meter level, and the horizontal positioning accuracy can be improved from 4–9 m to 3–6 m after TGD/DCB correction, and the elevation direction can be improved from 7–9 m to 5–7 m, and the improvement rate is about 10%–46%, which shows that DCB has a large impact on the single-point positioning accuracy and cannot be ignored in the positioning solution. -
表 1 QZSS服务时段内的可见星数及PDOP
测站 可见星数/颗 PDOP CCJ2 4 15.3 CKSV 4 15.7 CUSV 4 15.9 MCHL 4 16.4 MCIL 4 15.2 NCKU 4 15.6 均值 4 15.6 表 2 SPP TGD/DCB改正前后定位精度
策略 L1频点 L2频点 L1/L2频点 E N U E N U E N U 无改正/m 7.36 4.33 7.69 8.28 5.45 8.62 5.63 3.11 5.94 TGD改正/m 4.34 3.78 5.46 5.26 4.86 6.39 - - - DCB改正/m 4.00 3.10 5.07 4.43 3.96 5.97 - - - TGD提升率/% 41.06 12.57 28.98 36.46 10.82 25.92 - - - DCB提升率/% 45.58 28.37 34.05 46.54 27.29 30.80 - - - -
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