Fu Naifeng, Jiang Mingbo, Li Fenghui, Guo Peng, Hou Chunping, Wu Mengjie, Wu Jianming, Wang Zhipeng, Kan Liang
School of Marine Science and Technology, Tianjin University, Tianjin 300072, China.
Beijing Institute of Applied Meteorology, Beijing 100029, China.
Sensors (Basel). 2022 Jul 12;22(14):5209. doi: 10.3390/s22145209.
Global Navigation Satellite System (GNSS) signals generate slant tropospheric delays when they pass through the atmosphere, which is recognized as the main source of error in many spatial geodetic applications. The zenith tropospheric delay (ZTD) derived from radio occultation data is of great significance to atmospheric research and meteorology and needs to be assessed in the use of precision positioning. Based on the atmPrf, sonPrf, and echPrf data from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) Data Analysis and Archiving Center (CDAAC) from 1 January to 31 December 2008 and 2012, we obtained the ZTDs of the radio occultation data (occZTD) and the corresponding radiosonde (sonZTD) and ECWMF data (echZTD). The ZTDs derived from ground-based global positioning system (GPS) observations from the International GNSS Service (IGS) were corrected to the lowest tangent point height of the matched radio occultation profile by the barometric height formula (gnsZTD). The statistical results show that the absolute values of the bias between occZTD and echZTD, sonZTD, or gnsZTD are less than 5 mm, and the standard deviations are approximately 20 mm or less, indicating that occZTD had significant accuracy in the GNSS positioning model even when the local spherical symmetry assumption error was introduced when the Abel inversion algorithm was used to obtain the refractive index profile of atmPrf. The effects of the horizontal/vertical matching resolution and the variation in the station height/latitude on the biases of occZTD and gnsZTD were analyzed. The results can be used to quantify the performance of radio occultation data for tropospheric delay error correction in dynamic high-precision positioning.
全球导航卫星系统（GNSS）信号穿过大气层时会产生对流层斜延迟，这在许多空间大地测量应用中被认为是主要误差源。由无线电掩星数据推导得到的天顶对流层延迟（ZTD）对大气研究和气象学具有重要意义，在精密定位应用中需要对其进行评估。基于气象、电离层和气候星座观测系统（COSMIC）数据分析与存档中心（CDAAC）提供的2008年1月1日至12月31日以及2012年的atmPrf、sonPrf和echPrf数据，我们获取了无线电掩星数据的ZTD（occZTD）以及相应的探空仪数据（sonZTD）和欧洲中期天气预报中心（ECWMF）数据（echZTD）。通过气压高度公式将国际GNSS服务（IGS）基于地面全球定位系统（GPS）观测得到的ZTD校正到匹配无线电掩星剖面的最低切点高度（gnsZTD）。统计结果表明，occZTD与echZTD、sonZTD或gnsZTD之间偏差的绝对值小于5毫米，标准差约为20毫米或更小，这表明即使在使用阿贝尔反演算法获取atmPrf折射率剖面时引入了局部球对称假设误差，occZTD在GNSS定位模型中仍具有较高精度。分析了水平/垂直匹配分辨率以及测站高度/纬度变化对occZTD和gnsZTD偏差的影响。这些结果可用于量化无线电掩星数据在动态高精度定位中对流层延迟误差校正的性能。
