低成本GNSS对流层水汽变化监测OA

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.