顾及非线性高程归算的中国西北区域对流层天顶延迟模型

对流层延迟是影响高精度导航定位的关键因素,同时也是进行GNSS水汽反演的重要数据。中国西北区域地形起伏较大,目前中国西北地区对流层天顶延迟模型在高程方面顾及不足,无法满足实时高精度定位需求,因此建立高精度中国西北地区对流层延迟模型成为迫切需求。针对当前中国西北地区ZTD模型未同时顾及非线性高程归算以及季节变化等问题,本文将利用2015-2017年欧洲中期天气预报中心(ECMWF)的ERA5资料建立顾及非线性高程归算的中国西北地区对流层天顶延迟模型(MZTD模型)。联合未参与建模的2018年ERA5资料和中国西北陆态网84个GNSS测站数据,验证MZTD模型的精度和适用性,并与目前使用广泛的GPT3模型进行精度对比。结果表明：以2018年ERA5资料和中国西北陆态网测站数据为参考值,MZTD模型的均方根误差(RMS)分别为3.14cm和2.81cm,相对于GPT3模型精度分别提高了约16.3%和21.7%,同时MZTD减少模型参数,提升了模型计算效率。因此,顾及非线性高程归算的MZTD模型在中国西北区域体现了更好的精度和适用性,可以为中国西北地区进行实时GNSS水汽探测和导航定位提供重要参考。

ZenithSTroposphericSDelaySModelSinSNorthwestSChinaSConsideringSNonlinearSElevationSReduction

Atmospheric delay is a critical factor affecting high-precision navigation and GNSS water vapor inversion. The terrain in northwest China is highly variable, and the current zenith total delay (ZTD) model in this region does not adequately consider elevation, which cannot meet the real-time high-precision positioning needs. Therefore, it is urgently necessary to establish a high-precision ZTD model for northwest China. In this paper, the ERA5 data from the European Centre for Medium-Range Weather Forecasts (ECMWF) for 2015-2017 will be used to establish a ZTD model (MZTD model) for northwest China that considers non-linear elevation correction. This model addresses the problems of current ZTD models in northwest China, such as neglecting non-linear elevation correction and seasonal variations. The 2018 ERA5 data not involved in the modeling and the 84 GNSS stations data from the Northwest China land state network were jointly used to verify the accuracy and applicability of the MZTD model and to compare the accuracy with the GPT3 model, which is widely used today. We also compare the MZTD models accuracy with the widely used GPT3 model. The results show that, with 2018 ERA5 data and northwest China land network station data as reference values, the root mean square error (RMS) of the MZTD model is 3.14 cm and 2.81 cm, respectively, which is about 16.3% and 21.7% higher in accuracy than the GPT3 model. Moreover, the MZTD model has fewer model parameters, improving computational efficiency. Therefore, the MZTD model that considers non-linear elevation correction demonstrates better accuracy and applicability in the northwest China region, providing important references for real-time GNSS water vapor detection and navigation positioning in this area.