Boisits Janina, Glaner Marcus, Weber Robert
Research Division Higher Geodesy, Department of Geodesy and Geoinformation, TU Wien, Vienna 1040, Austria.
Sensors (Basel). 2020 May 16;20(10):2845. doi: 10.3390/s20102845.
Propagation delays of GNSS signals caused by the ionosphere can range up to several meters in zenith direction and need to be corrected. Geodetic receivers observing at two or more frequencies allow the mitigation of the ionospheric effects by forming linear combinations. However, single frequency users depend on external information. The ionosphere delay model Regiomontan developed at TU Wien is a regional ionospheric delay model providing high accuracy information with a latency of only a few hours. The model is based on dual-frequency phase observations of a regional network operated by EPOSA (Echtzeit Positionierung Austria) and partners. The corrections cover a geographical extent for receiver positions within Austria and are provided in the standardized IONEX format. The performance of Regiomontan as well as its application in Precise Point Positioning (PPP) were tested with our in-house PPP software raPPPid using the so-called uncombined model with ionospheric constraint. Various tests, e.g., analyzing the coordinate convergence behavior or the difference between estimated and modeled ionospheric delay, proving the high level of accuracy provided with Regiomontan. We conclude that Regiomontan performs at a similar level of accuracy as IGS final TEC maps, but with explicitly reduced latency.
电离层引起的全球导航卫星系统（GNSS）信号传播延迟在天顶方向可达数米，需要进行校正。在两个或更多频率上进行观测的大地测量接收机可以通过形成线性组合来减轻电离层的影响。然而，单频用户则依赖外部信息。维也纳工业大学开发的电离层延迟模型Regiomontan是一种区域电离层延迟模型，能以仅几小时的延迟提供高精度信息。该模型基于由奥地利实时定位（EPOSA）及其合作伙伴运营的区域网络的双频相位观测数据。这些校正覆盖奥地利境内接收机位置的地理范围，并以标准化的IONEX格式提供。我们使用内部的PPP软件raPPPid，采用带有电离层约束的所谓非组合模型，对Regiomontan的性能及其在精密单点定位（PPP）中的应用进行了测试。各种测试，例如分析坐标收敛行为或估计电离层延迟与模型电离层延迟之间的差异，都证明了Regiomontan所提供的高精度水平。我们得出结论，Regiomontan的精度水平与国际GNSS服务（IGS）最终电离层总电子含量（TEC）地图相当，但延迟明显降低。
