北斗二代导航卫星系统地壳运动监测能力

Crustal Deformation Monitoring by BDS-2 Regional Navigation Satellite System

为了评估北斗卫星导航系统(BeiDou navigation satellite system,BDS)监测中国大陆地区地壳变形的技术能力,利用GAMIT/GLOBK软件处理了2017—2019年中国大陆构造环境监测网络23个基准站的全球定位系统(global positioning system,GPS)与BDS-2双模观测数据。结果显示,北斗二代的水平和垂向单日测站定位精度分别约为5~7 mm和13 mm,基线相对定位精度水平分量达到3~4 mm+(1~2)×10^(-8),水平位移速度测定精度约为0.6 mm/a。北斗二代的精密定位水平大致与20世纪90年代初GPS相当,可用于测定大尺度的板块运动及板内变形,但受卫星星座和定轨精度限制,不能准确反映季节性变动状态。作为对现有GPS监测的补充,可将基准站3年尺度的地壳运动监测精度最多提高20%。

Objectives:With the development of BeiDou navigation satellite system(BDS),many researchers focus on its high precision application,especially in crustal deformation and earthquake prediction.In order to assess the performance of BDS-2 as Chinese regional navigation satellite system in monitoring active deformation,we used GAMIT/GLOBK software to analyze the positioning time series of global positioning system(GPS)and BDS-2 at 23 stations in the crustal movement observation network of China(CMONOC).Methods:Firstly,we used general Gauss-Markov error model to regard the time series as the combination of white noise and color noise.Secondly,we calculated weighted root mean square(WRMS)of the residues to show the positioning errors under long-lasting observation.Finally,the principal component analysis method was applied to get the main components of commode errors.Results:The data processing results show that the root mean square deviation of BDS-2 daily solutions achieves 5-7 mm in horizontal component and 13 mm in vertical component.Based on the statistics of 22 independent baselines,we demonstrate the relative positioning precision of BDS-2 is 3-4 mm+(1-2)×10^(-8).Moreover,we find that 3-year continuous observations enable a typical velocity uncertainty of 0.6 mm/a for the plate motion.Conclusions:The accuracy of high-precision positioning of BDS-2 is comparable to that of GPS in the early 1990s.Due to imprecise orbit determination and imperfect constellation geometry,BDS-2 time series in vertical component do not provide sufficient information of seasonal variations in surface loading.The estimation of BDS-2 velocities can be used as a supplement to GPS and improve the monitoring accuracy by up to 20%for the CMONOC stations.