HY2D星载北斗数据质量评估及事后精密定轨精度分析

HY2D Satellite Onboard BDS-3 Data Quality Evaluation and Post-precise Orbit Determination Accuracy Analysis

基于海洋二号D卫星(HY2D)2021年7月7-16日(年积日Day Of Year(DOY)188-197)的星载北斗观测数据,从测量数据有效性、可见卫星数量、位置精度因子及伪距多路径效应等角度分析了数据质量,并利用其进行事后精密定轨,从相位残差、重叠弧段、轨道互比和激光检核4种手段评估了定轨结果精度.结论如下:(1)HY2D卫星接收北斗三号卫星数在4颗及以上占比约为86.66%;B1C频点多路径误差RMS(Root mean square)约为0.37 m,B2a频点约为0.18 m.(2)载波相位拟合残差RMS在6-8 mm之间;相邻轨道重叠4 h的位置差异小于2 cm,与法国CNES(Centre National d‘Etudes Spatiales)DORIS(Doppler Orbitography and Radio-positioning Integrated by Satellite)轨道比较径向RMS优于1.9 cm.(3)用激光测距数据检核轨道精度,其星距残差的RMS约为3.24 cm.结果表明,国产星载双频北斗接收机可以完成海洋测高卫星的精密定轨指标.

Haiyang-2D(HY2D)satellite orbits with different arc lengths are determined based on BDS-3(BeiDou-3)data collected from the onboard GNSS(Global Navigation Satellite System)receivers between July 7th and 16th,2021(day of year 188-197).The data quality of space-borne BDS-3 for HY2D satellites is analyzed from the aspects of satellite visibility,DOP(Dilution Of Precision)value,multipath effects.Meanwhile,the post-precise orbit accuracy is assessed using a number of tests,which include analysis of observation residuals,arc overlaps,orbit external-comparisons,and satellite laser ranging(SLR)residuals.The results indicate that:(1)Over 86.66%epochs with 4 BDS-3 satellites available.The multipath error RMS(Root Mean Square)for B1C frequency is about 0.37 m,and for B2a frequency,it is around 0.18 m.(2)Carrier phase fitting residuals range from 6 to 8 mm.The POD(Precise Orbit Determination)precision with only BDS-3 data is evaluated by overlap comparison,showing good orbit consistency at 2 cm level(3D RMS).As for external orbit validation,the radialRMS compared with the CNES(Centre National d’Etudes Spatiales)DORIS(Doppler Orbitography and Radio-positioning Integrated by Satellite)orbit is better than 1.9 cm.(3)The mean of SLR validation residual RMS is 3.24 cm.These results demonstrate that domestically-produced dual-frequency BDS receivers can meet the satellite's centimeter-level radial orbit determination requirements for altimetry satellites.