【作者】 杨玲； 李博峰； 沈云中；

【Author】 YANG Ling~1,Li Bofeng~2,SHEN Yunzhong~(1,3) 1 Dept.of Surveying and Geo-informatics Engineering,Tongji University,Shanghai 200092,China2 2 GNSS Research Centre,Department of Spatial Science,Curtin University of Technology,Perth WA 6845,Australia

【机构】 同济大学测量与国土信息工程系； GNSS研究中心空间信息系科廷科技大学； 现代工程测量国家测绘局重点实验室；

【摘要】 网络RTK的关键是参考站间模糊度快速、可靠地固定。影响模糊度固定的因素非常复杂,且随实际观测环境的变化而变化,因此很难从理论上严格分析。已有研究大多集中在分析大气误差对模糊度固定的影响,本文将分析截止卫星高度角、基线长度、以及特定时间等因素对模糊度固定速度及成功率的影响。首先采用相位和伪距观测值构成的MW组合固定宽巷模糊度,然后,采用宽巷模糊度固定的无电离层组合观测值按Kalman滤波算法求解相对天顶对流层延迟参数和窄巷模糊度参数,并利用一定准则搜索固定部分窄巷模糊度参数。实验采用上海和美国CORS网的GPS实测数据分析,结果表明,经对流层基本模型改正后的相对湿对流层延迟数值上并不随基线增长而显著增加,但变化比较复杂,对于低高度角观测值的影响显著;且截止高度角过高会对RZTD参数解算产生不利影响;双差电离层延迟在每天地方时2PM后迅速增大,这也制约着长距离网络RTK模糊度求解和RZTD参数的解算。更多还原

【Abstract】 Fast and reliable ambiguity resolution is the key to Network RTK.The factors impacting the resolution of integer ambiguities are very complicated and vary with the change of real environment,so it is difficult to analyze them theoretically.Previous study focuses on the influence of atmospheric errors on ambiguity fixing.Whereas,in this paper,we analyze the relationship between the efficiency as well as success rate of ambiguity resolution and several factors,such as the different length of baseline,the changes of satellite cut-off elevation angle,as well as certain time strip.We first use the MW combinations formed by phase and pseudo-range DD observables to fix the wide-lane ambiguities.Afterwards,accurate residual Relative Zenith Tropospheric Delay(RZTD) as well as the float Narrow-lane(NL) ambiguities are estimated using the Ionosphere-free(IF) observables which are corrected by the fixed WL ambiguities via a Kalman filter.When the estimated float NL ambiguity meets certain criteria,this ambiguity will then be fixed.The test data comes from Shanghai CORS network and American NGS-CORS network.Test results demonstrate that RZTD does not increase remarkably as the lengthening of baseline,while the variation is complicated,which results in a significant effect to the low elevation satellites.Besides,higher cut-off elevation angle makes an adverse effect on the estimation of RZTD.Moreover,DD ionospheric delay fluctuates dramatically after the local time 2PM,which also impacts the estimation precision of ambiguity resolution and RZTD parameters.更多还原