GGOS对流层延迟产品精度分析及在PPP中的应用

发布时间：2018-08-12 20:24

【摘要】：对流层延迟是卫星导航定位的主要误差源,GNSS广域增强需要高精度的对流层延迟产品进行误差修正。对流层延迟可通过GNSS进行实时估计,也可通过融合多源数据的数值气象预报模型获取。IGS发布的全球对流层天顶延迟产品由GNSS解算,其精度可达4mm,时间分辨率为5min,但其分布不均匀,在广袤的海洋区域无数据覆盖。GGOS Atmosphere基于ECMWF 40年再分析资料,可提供1979年以来时间分辨率为6h、空间分辨率为2.5°×2°的全球天顶对流层总延迟格网数据。本文通过2015年全球IGS测站的ZTD资料对GGOS的ZTD产品进行了评估,研究了GGOS Atmosphere对流层延迟产品与IGS发布ZTD资料之间的系统差,通过线性拟合估计出每个测站GGOS-ZTD与IGSZTD系统差系数(包括比例误差a和固定误差b),然后对比例误差a、固定误差b进行球谐展开,建立了两种ZTD数据源之间的系统差模型。选取IGS测站和陆态网测站,对附加系统偏差改正后的GGOSZTD产品对PPP的收敛速度的影响进行研究。本文研究结果表明:GGOS-ZTD与IGS-ZTD间存在系统偏差,其bias平均为-0.54cm;两者之间较差的RMS平均为1.31cm,说明GGOS-ZTD产品足以满足广大GNSS导航定位用户对对流层延迟改正的需要。将改正了系统差后的GGOS-ZTD产品用于ALBH、DEAR、ISPA测站、PALM测站、ADIS测站、YNMH测站、WUHN测站进行PPP试验,发现可明显提高定位收敛速度,尤其是在U方向上,收敛速度分别提高10.58%、31.68%、15.96%、43.89%、51.46%、14.69%、18.40%。
[Abstract]:Tropospheric delay is the main error source for satellite navigation and positioning. GNSS wide area enhancement requires high accuracy tropospheric delay products for error correction. The tropospheric delay can be estimated in real time by GNSS, and the global tropospheric zenith delay product released by GNSS can also be obtained by using the numerical weather forecast model with multi-source data, and the global tropospheric zenith delay product can be calculated by GNSS. Its accuracy can reach 4 mm, time resolution is 5 min, but its distribution is uneven. There is no data coverage. GGOS Atmosphere is based on ECMWF 40 years reanalysis data. The global zenith tropospheric total delay grid data with a temporal resolution of 6 h and a spatial resolution of 2.5 掳脳 2 掳since 1979 can be provided. Based on the ZTD data of global IGS station in 2015, this paper evaluates the ZTD products of GGOS, and studies the system difference between GGOS Atmosphere tropospheric delay products and ZTD data released by IGS. The differential coefficients of GGOS-ZTD and IGSZTD system (including proportional error a and fixed error b),) are estimated by linear fitting. Then the spherical harmonic expansion of proportional error a and fixed error b is carried out, and the system difference model between two kinds of ZTD data sources is established. IGS stations and land-based network stations are selected to study the effect of the GGOSZTD product after the correction of the additional system deviation on the convergence rate of the PPP. The results show that there is a systematic deviation between IGS-ZTD and GGOS-ZTD, the average bias is -0.54 cm, and the average RMS between the two is 1.31 cm, which indicates that the GGOS-ZTD product can meet the needs of GNSS navigation users for tropospheric delay correction. The GGOS-ZTD product, which has been corrected, is used in the PPP test of the pan station and the YNMH station. It is found that the convergence rate of the positioning can be improved obviously, especially in the U direction, and the convergence rate is increased by 10.58%, 31.68%, 43.89%, 51.46%, 14.69% and 18.40%, respectively, in the direction of U, and the following results are obtained: (1) in the direction of U, the speed of convergence is 10.58%, especially in the direction of U, the convergent speed is increased by 10.58% and 31.68%, respectively, and the speed of convergence is increased by 51.46% and 14.69%.
【作者单位】：武汉大学测绘学院;
【分类号】：P228.4

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