分区综合改正:服务于北斗分米级星基增强系统的差分改正模型

针对分米级星基增强服务的需求，提出一种满足用户基于相位观测值进行单站定位的分区综合改正模型。该模型利用参考站网的观测数据，实时计算参考站对每颗卫星伪距和相位观测值的综合改正数，并将综合改正数按照分区的方式编排到广播电文并广播给用户使用。本文介绍了模型的原理，并分析了参数播发频度、用户站与分区中心距离等因素对用户定位的影响。建立基于分区综合改正数的星基增强数据处理系统，采用分布于中国不同区域的北斗观测站数据对系统性能进行评估。结果表明，双频用户动态定位平均10 min内收敛至误差小于1 m，平均平面精度能达到15 cm，高程精度达到20 cm。

Zone Correction:A SBAS Differential Correction Model for BDS Decimeter-level Positioning

To support the requirement of decimeter-level BDS SBAS service,a type of differential correction,the "zone correction",it is developed. It represents the remaining un-modeled errors of pseudo-range and carrier phase observations,and could be encoded into the current broadcast messages.The zone correction is derived using observations of reference stations,where their coordinates are precisely known. Users receiving the broadcast zone corrections covering its region,use them to correct the observations,thus the observation modeling errors are reduced and positioning accuracy can be improved.It is analyzed that the impact of parameter updating rates and the distance between users and the zone center on the user positioning accuracy. Data of the BDS tracking network in the China continent is used to validate the proposed model.Results show that mean positioning accuracy reaches 15 cm and 20 cm for horizontal and height components,respectively.