【摘要】 目前,全球卫星导航系统(GNSS)已进入以GPS、GLONASS、BDS、Galileo四系统为代表的多系统并存的时代,多系统多频率观测值的综合应用极大地提升了GNSS的服务能力.GNSS自身的数据质量是取得高精度结果的先决条件之一,也是多系统精密定位随机模型构建的关键.为避免码分多址和频分多址机制不同的影响,本文采用几何无关和M-W组合方法,基于科廷大学实测零基线数据对四系统的载波相位单差残差序列对比分析,并利用高度角随机模型中的正弦模型和指数模型对载波相位观测值精度随高度角变化建模,获得适用于不同系统不同频率观测值的随机模型.实验分析表明,单差残差序列随高度角变化情况在不同系统不同频率表现出不同特性;Galileo系统L1、L2观测值精度相当,均在0.9mm左右,其他系统则表现出L2精度比L1精度更差的性质.高度角加权模型拟合结果表明,正弦模型和指数模型对GPS和Galileo系统的L1、L2精度序列拟合一致性较好,而BDS系统使用正弦模型拟合效果略差,GLONASS系统则不适合采用正弦模型评估L2观测值精度.更多还原

【Abstract】 Besides GPS and GLONASS,Galileo and BDS are developing fast,a multiGlobal Navigation Satellite System(multi-GNSS)age is emerging,which brings a great opportunity to improve the quality of Positioning,Navigation and timing(PNT)by combining multi-GNSS and multi-frequency data.The data quality of GNSS itself is one of the preconditions for achieving high-precision results,and it is also the key to construction of stochastic model in multi-GNSS precise positioning.In order to avoid the negative effects of Code Division Multiple Access(CDMA)and Frequency Division Multiple Access(FDMA)mechanism for different GNSS systems,this paper used Geometry-free and M-W combination method to compare and analyze carrier phase single-difference(SD)residual time series for four systems where data of a zero baseline measured in Curtin University are adopted.Meanwhile,elevation-dependent stochastic models are obtained for each GNSS system based on the sinusoidal model and the exponential model.The experimental results show that the SD residual series perform different characteristics in different frequencies and systems.The precision of L1 and L2 observations in Galileo system is quite similar and about 0.9 mm;however,precision of L2 observations in other systems is even worse than that of L1.The fitting results of elevation-dependent model show that the sinusoidal model and exponential model have a good consistency with precision of L1 and L2 observations of GPS and Galileo,while the sinusoidal model has a slightly worse fitness in BDS system,and using sinusoidal model to evaluate the accuracy of L2 observations in GLONASS system is inappropriate.更多还原