一种优化的对流层天顶延迟融合模型FZTD

A optimized fusion zenith tropospheric delay model-FZTD

对流层延迟是影响全球卫星导航系统(GNSS)定位精度的主要误差源之一,模型修正法是目前削弱对流层延迟影响的主要方法.以简单易用的角度为切入点,综合UNB3模型的简易性和GPT2w模型的高精度特点,构建一种简易且精度较高的对流层天顶延迟融合模型(FZTD).并利用多年的国际GNSS服务(IGS)对流层天顶延迟(ZTD)数据对该模型精度进行了验证.结果表明FZTD模型的均方根(RMS)与平均偏差(bias)值分别为4.4 cm和-0.3 cm,均小于传统模型UNB3m(RMS:5.1 cm,bias:1.1 cm)和EGNOS(RMS:5.1 cm,bias:0.3 cm),定位精度提高了14%,而且在南半球提高尤为明显,特别在南极地区,精度提高了近3倍,弥补了传统模型在南北半球精度差异大的不足.新模型总气象参数仅为120个比GPT2w模型急剧减少,与传统模型相当,为GNSS实时导航定位终端的预定义对流层延迟改正提供了更优的选择.

Tropospheric delay is one of the main error sources that affect the accuracy of Global Navigation Satellite System(GNSS)navigation and positioning.One effective way to weaken the influence of tropospheric delay is the model correction method.This paper has proposed a simple and accurate fusion tropospheric delay model(FZTD)by combining the simplicity of the UNB3 model and the high-precision characteristics of the GPT2 w model.The accuracy of the purposed model was verified by using the International GNSS Service(IGS)troposphere zenith delay(ZTD)data over 2011—2015.The results show that root mean square(RMS)and bias values of the FZTD model are 4.4 cm and-0.3 cm,respectively,which are smaller than the traditional models UNB3 m(RMS:5.1 cm,bias:1.1 cm)and EGNOS(RMS:5.1 cm,bias:0.3 cm).Its global accuracy has increased by 14%,and the improvement is particularly obvious in the southern hemisphere,especially in the Antarctic region,the accuracy has increased by nearly 3 times.The FZTD model makes up for the shortcomings of the traditional models that there are large differences in accuracy between the northern and southern hemispheres.The total meteorological parameters of the new model are only 120,which are drastically reduced compared to the GPT2w model,which makes it possible to be hardwired in the GNSS receivers.