BDS多路径误差特性研究

发布时间：2018-07-07 22:36

本文选题：多路径误差 + BDS　；参考：《中国矿业大学》2017年硕士论文

【摘要】：近年来,我国自主研发设计的北斗卫星导航定位系统(BDS)得到了迅猛发展,并已具备了在亚太地区向用户提供实时高精度的定位、导航、授时服务的能力。随着BDS系统的不断完善及研究的不断深入,BDS已经具备了高精度定位的能力,并已成功应用于高精度的变形监测中。在大型建筑物、桥梁、大坝等复杂环境下的变形监测中,BDS定位结果易受到各种误差的影响,通常在站间、星间求双差可消除对流层误差、电离层误差、接收机钟差等误差的影响。而由测站环境引起的信号干涉形成的多路径误差成为了影响定位结果的重要误差源。因此如何减弱该误差对定位结果的影响,成为BDS高精度变形监测中不可忽视的重要问题。论文针对BDS多路径误差问题,对多路径误差数学模型、BDS多路径误差特性、滤波方法及多路径误差建模及改正措施等,进行了广泛研究。本文的主要工作和成果可归纳如下:1、研究了多路径误差数学模型,分析了多路径误差的周期、频率等特征。重点研究了影响多路径误差大小的相关因素,并详细给出了反射系数、反射体到接收机天线的水平距离及反射信号的入射角等,对多路径误差影响。2、为获取BDS多路径误差特性,研究总结了BDS不同星座结构卫星的轨道运行特性,通过对实测数据处理,发现了不同星座结构卫星具有不同的轨道运行重复周期,如GEO、IGSO卫星的轨道重复周期约为1个恒星日,MEO卫星对应的轨道重复周期约为7个恒星日。且各个卫星对应的轨道重复周期在不同时刻具有不同的时间提前量。为此,在论文中引入了单差残差法,通过分析各个卫星对应的载波相位观测值单差残差在相邻两天间的相关性,发现了在互相关系数取得最大值的位置信息,与该卫星对应轨道重复周期的时间提前量相符合。验证了采用基于载波相位观测值单差残差提取多路径误差并进行改正的可行性。3、介绍了多路径误差建模中常用的滤波方法。通过模拟信号,总结了最佳小波基函数及对应最佳分解层数确定的方法,确定了sym6小波及最佳分解层数。并对比了EMD分解的滤波性能。最后将两种方法用于实测BDS数据的多路径误差建模及改正。验证了sym6小波用于减弱BDS多路径误差,提高定位结果精度的优越性。
[Abstract]:In recent years, the Beidou Satellite Navigation and Positioning system (BDS), which has been developed and designed independently in China, has been developed rapidly and has the ability to provide real-time and high-precision positioning, navigation and time service to users in the Asia-Pacific region. With the continuous improvement of BDS system and the deepening of research, BDS has the ability of high-precision positioning, and has been successfully applied in high-precision deformation monitoring. In the deformation monitoring of large buildings, bridges, dams and other complex environments, the results of BDS positioning are easily affected by various errors. In general, the error of troposphere and ionosphere can be eliminated by calculating the double difference between satellites. The influence of receiver clock error. The multipath error caused by the signal interference is an important error source. Therefore, how to reduce the influence of this error on the positioning results has become an important problem in BDS high precision deformation monitoring. Aiming at the problem of multipath error of BDS, the characteristics of multipath error, filtering method, modeling and correcting measures of multipath error are studied extensively in this paper. The main work and results of this paper can be summarized as follows: 1. The mathematical model of multipath error is studied, and the characteristics of period and frequency of multipath error are analyzed. The factors influencing the multipath error are studied in detail. The reflection coefficient, the horizontal distance from the reflector to the receiver antenna and the incident angle of the reflected signal are given in detail. The orbit characteristics of BDS satellites with different constellation structures are summarized. By processing the measured data, it is found that different constellation satellites have different orbit repeat periods. For example, the orbit repetition period of GEOOGSO satellite is about 1 star day and the corresponding orbit repeat period of MEO satellite is about 7 star days. And the orbit repeat period of each satellite has different time advance at different time. For this reason, the single difference residual method is introduced in this paper. By analyzing the correlation between the carrier phase observation values of each satellite and the adjacent two days, the position information of the maximum value in the number of mutual relations is found. It coincides with the time advance of the satellite's corresponding orbit repetition period. The feasibility of extracting and correcting multipath errors based on carrier phase observations is verified. The filtering methods commonly used in multipath error modeling are introduced. The method of determining the optimal wavelet basis function and the corresponding optimal decomposition layer number is summarized through the analog signal, and the sym6 wavelet and the optimal decomposition layer number are determined. The filtering performance of EMD decomposition is compared. Finally, two methods are used to model and correct the multipath error of BDS data. The superiority of sym6 wavelet to reduce the multipath error and improve the accuracy of location results is verified.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN967.1

【参考文献】