GPS/Galileo组合区域增强PPP算法与评估

Algorithm and assessment of GPS/Galileo combined regional augmented PPP

为了提高区域增强精密单点定位(PPP)系统参考站端非差模糊度的固定效率,设计了一种改进的GPS/Galileo组合区域增强PPP参考站和用户端的核心算法,提出了以消除接收机相关误差的固定单差模糊度作为约束,辅助非差模糊度固定的方法.研究了算法中基准与偏差项在参考站与用户间和不同参数间传递的过程,明确了大气延迟改正数中包含混合基准的具体成分.利用美国CORS站网的观测数据进行区域增强PPP模糊度固定解算实验,评估了GPS/Galileo组合系统可提供的解算效果及其相对于GPS单系统的增益.结果表明:相较于GPS单系统,当使用组合系统时用户PPP模糊度成功固定率提高4.5%,达到96.1%,可以在全天绝大多数时间提供正常服务,同时正确固定率提高2.9%;模糊度固定所需的时间节省了约13%.

In order to improve the efficiency of fixing the undifferenced ambiguities at the reference end in regional augmented precise point positioning(PPP)system,the modified algorithm for global positioning system(GPS)and Galileo satellite navigation system(Galileo)combined regional augmented PPP at both reference stations and users is designed.A method for fixing the undifferenced ambiguity by using the fixed single-differenced ambiguity eliminating the receiver-related biases as the constraint is presented.The transfer process of basis and biases terms between user and reference stations and between different parameters is studied.The specific components in the mixed basis of the atmospheric corrections are illustrated.The real observation data from the American CORS network are utilized to conduct the regional augmented PPP ambiguity resolution(AR)experiments.The solution performance of GPS/Galileo combined system and its gain relative to GPS single system are evaluated.The results show that when the combined system is used,compared with single GPS results,the success fix rate increases by 4.5%,reaching 96.1%,showing that the system can provide normal service at most of the time in a day.Meanwhile,the correct fix rate is improved by 2.9%.Thus,the time required to fix the ambiguity is shortened by about 13%.