A grid-based tropospheric product for China using a GNSS network
A grid-based tropospheric product for China using a GNSS network
复制标题
使用 GNSS 网络为中国提供基于网格的对流层产品
DOI：
10.1007/s00190-017-1093-z
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发表时间：
2018
影响因子：
4.4
通讯作者：
Ou Jikun
中科院分区：
文献类型：
--
作者：
Zhang Hongxing;Yuan Yunbin;Li Wei;Zhang Baocheng;Ou Jikun
对流层延迟是全球导航卫星系统误差的一个来源。为了更好地表征对流层延迟的时空特性，促进GNSS在中国的安全使用，提出了一种基于对流层经验模型的GNSS网络生成网格化对流层产品（GTP）的方法。原型系统生成的GTP在后处理和实时模式，是基于非差分和非组合精密单点定位（UU-PPP）技术。在中国大陆上建立了时间分辨率为5 min的经纬度网格地形。实时GTP消息以自定义的RTCM 3格式进行编码，并使用NTRIP（通过互联网协议进行RTCM的网络传输）广播给用户，从而实现向实时用户的高效和安全传输。我们的GTP生成方法包括三个连续的步骤。在第一步中，使用UU-PPP估计GNSS站点网络的GNSS导出的天顶对流层延迟（ZTD）。在第二步中，对GNSS导出的ZTD进行垂直调整，以解决GNSS台站和网格点之间的高度差。ZTD高度校正由IGGtrop模型提供。最后，使用逆距离加权方法将来自周围GNSS站的GNSS导出的ZTD内插到网格点的位置。利用中国地壳运动观测网络中的210个全球定位系统（GPS）台站，采用后处理和实时两种方式生成全球定位点。在12个测试GPS站，分别与ERA中期衍生的ZTD和GPS衍生的ZTD的GTP的精度进行了评估。结果表明，后处理和实时GTP可以提供ZTD的精度为1.4和1.8厘米，分别。将该方法应用于实时动态GPS PPP中，结果表明，PPP解的收敛时间缩短。这些结果证实，全球定位系统可以作为一个有效的信息源，以增强全球导航卫星系统定位在中国。
Tropospheric delay accounts for one source of error in global navigation satellite systems (GNSS). To better characterize the tropospheric delays in the temporal and spatial domain and facilitate the safety-critical use of GNSS across China, a method is proposed to generate a grid-based tropospheric product (GTP) using the GNSS network with an empirical tropospheric model, known as IGGtrop. The prototype system generates the GTPs in post-processing and real-time modes and is based on the undifferenced and uncombined precise point positioning (UU-PPP) technique. GTPs are constructed for a grid form (latitude–longitude) over China with a time resolution of 5 min. The real-time GTP messages are encoded in a self-defined RTCM3 format and broadcast to users using NTRIP (networked transport of RTCM via internet protocol), which enables efficient and safe transmission to real-time users. Our approach for GTP generation consists of three sequential steps. In the first step, GNSS-derived zenith tropospheric delays (ZTDs) for a network of GNSS stations are estimated using UU-PPP. In the second step, vertical adjustments for the GNSS-derived ZTDs are applied to address the height differences between the GNSS stations and grid points. The ZTD height corrections are provided by the IGGtrop model. Finally, an inverse distance weighting method is used to interpolate the GNSS-derived ZTDs from the surrounding GNSS stations to the location of the grid point. A total of 210 global positioning system (GPS) stations from the crustal movement observation network of China are used to generate the GTPs in both post-processing and real-time modes. The accuracies of the GTPs are assessed against with ERA-Interim-derived ZTDs and the GPS-derived ZTDs at 12 test GPS stations, respectively. The results show that the post-processing and real-time GTPs can provide the ZTDs with accuracies of 1.4 and 1.8 cm, respectively. We also apply the GTPs in real-time kinematic GPS PPP, and the results show that the convergence time of the PPP solutions is shortened. These results confirm that the GTPs can act as an efficient information source to augment GNSS positioning over China.