低成本GNSS对流层水汽变化监测  

Tropospheric water vapor variation monitoring based on low-cost GNSS

作　　者：徐冬宇 陈雯[1] 张成龙 鹿然 XU Dongyu;CHEN Wen;ZHANG Chenglong;LU Ran(School of Geographical Sciences,East China Normal University,Shanghai 200241,China;National Engineering Center for Satellite Positioning System,Wuhan University,Wuhan 430072,China)

机构地区：[1]华东师范大学地理科学学院,上海200241 [2]武汉大学国家卫星定位系统工程技术研究中心,武汉430072

出　　处：《全球定位系统》2024年第6期95-103,共9页Gnss World of China

基　　金：国家自然科学基金项目(41771475)。

摘　　要：当前,利用GNSS反演大气可降水量(precipitable water vapor,PWV)主要依赖于地面观测站,考虑到成本限制,无法实现密集部署.低成本双频接收机的出现使得利用GNSS密集监测对流层水汽变化成为可能,为了进一步提高低成本设备探测PWV的精度,本文基于精密单点定位(precisepointpositioning, PPP)技术,对比了低成本双频接收机u-blox单系统GPS与GPS+BDS+GLONASS+Galileo 4个系统融合下估计天顶对流层延迟(zenith tropospheric delay,ZTD)的精度,通过第五代全球气候再分析数据集(ERA5)验证低成本设备的GNSS PWV精度,并分析降雨前后PWV的变化过程.实验结果显示,低成本的u-blox模块在估计ZTD方面能够达到与天宝大地测量型接收机相当的质量水平,多系统融合相比单系统获取到的ZTD序列更加稳定、准确,ZTD精度在平均绝对误差(mean absolute error,MAE)和均方根误差(root mean square error,RMSE)上分别提升28%和30%.与ERA5数据计算得到的PWV相比,低成本设备的MAE和RMSE分别为2.81 mm和3.72 mm,而天宝接收机的相应值分别为2.31 mm和3.04 mm,低成本设备的PWV反演精度略低于天宝接收机.尽管如此,在降雨期间,低成本设备仍能有效地反映PWV与实际降雨量之间的变化关系,满足天气预报等气象应用的需求.以上分析结果表明,低成本消费级GNSS接收机在规模化密集监测对流层水汽变化方面具有巨大的应用潜力.Current methodologies for calculating precipitable water vapor(PWV)from global navigation satellite system(GNSS)predominantly rely on ground-based observatories,which cannot be densely deployed considering the cost constraints.The emergence of low-cost dual-frequency receivers has made it possible to intensively monitor tropospheric water vapor changes,and in order to further improve the accuracy of detecting PWV by low-cost devices,in this paper,we employ the precise point positioning(PPP)method to compare the accuracy of the zenith tropospheric delay(ZTD)in single-system(GPS)and multi-system modes(GPS+BDS+GLONASS+Galileo)via an economical dual-frequency receiver u-blox,authenticate the PWV data accuracy derived from budget-friendly equipment against the fifth major global reanalysis(ERA5),and analyze the change process of PWV before and after rainfall.The experimental outcomes illustrate that the economical u-blox module attains ZTD estimations on par with those from pricier geodetic receivers,the multi-system fusion is more stable and more accurate than a single-system,and the ZTD accuracy is improved in terms of mean absolute error(MAE)and root mean square error(RMSE)by 28%and 30%,respectively.Nonetheless,when contrasted with ERA5 PWV,the PWV values obtained from the cost-effective device was 2.81 mm and 3.72 mm at MAE and RMSE,respectively.In comparison,the equivalent metrics for the high-end receiver stand at 2.31 mm and 3.04 mm,indicating a marginally inferior accuracy of PWV inversion with the economical device relative to its high-end counterpart.Despite this,during periods of rainfall,the low-cost apparatus proficiently delineates the correlation between PWV and actual precipitation,adequately satisfying the exigencies of meteorological pursuits such as weather prediction.These insights show that low-cost consumer-grade GNSS receivers have huge application potential in large-scale and intensive monitoring of tropospheric water vapor variation.

关 键 词：GNSS 大气可降水量(PWV) 低成本 精密单点定位(PPP) 对流层延迟 

分 类 号：P228.4[天文地球—大地测量学与测量工程]