基于小波变换的北斗周跳修复方法

发布时间：2018-03-13 10:47

本文选题：北斗卫星导航系统　切入点：周跳探测　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：北斗导航系统是我国自主研发的导航定位系统,完全建成之后可为全球用户提供导航定位服务,是继美国的GPS和俄罗斯的GLONASS之后又一成熟的导航定位系统。北斗导航系统已经在国民生产生活的多个领域发挥巨大的作用,对社会的发展带来很大的效益。载波相位观测量是导航系统中的重要观测量,具有广泛应用,周跳问题又是载波相位应用技术中的特有问题。周跳的存在影响北斗导航定位的准确性,使用载波相位观测值进行高精度定位时必须保证观测值的"干净",因此进行周跳探测修复是载波相位观测值使用中一项至关重要的工作。论文首先介绍了北斗导航系统目前的发展状况,从载波相位观测值的使用入手,引入了载波观测值中存在的周跳问题。阐述了北斗导航系统的信号特征,基本观测量及其线性组合,导航定位中存在的误差及其误差处理方法。阐述关于周跳的基本理论,如定义和产生的原因,对定位精度的影响,探测周跳时检测量的构造等。对几种常用周跳检测量做了对比分析,总结了各自优缺点,并最终选择双差检测量作为本次论文实验的周跳检测量。其次,论文以GPS周跳探测与修复方法为基础,分析了小波变换法在周跳探测修复中的应用现状。小波变换常被用来进行周跳探测而非周跳修复,论文对小波变换法做了进一步的探讨研究,提出用小波变换法探测周跳后,直接进一步修复周跳的方法。其基本原理是利用小波变换对检测序列进行多尺度分解,不含周跳时序列是光滑的,若分解之后高频系数出现奇异值,说明存在周跳。对奇异值插值替换,再将替换之后的高频系数和低频系数组合进行重构信号,与原始信号做差,得到周跳位置的差值,进行周跳修复。通过对修复之后的序列再次检测,如果高频系数依然存在奇异值,则继续替换修复。重复以上步骤,直到高频系数不再出现奇异值为止,即完成周跳修复。北斗系统存在地球静止轨道卫星,这是GPS系统中没有的,其对观测值影响较大,因此构造双差检测量时充分考虑到北斗的这一独特性。最后,论文进行具体的实例分析,验证了所提方法的有效性,小波变换可以直接修复周跳。同时发现了其中的不足,即修复过程是逐次完成的。概括了本文所做的工作和取得的成果,为之后的相关研究奠定基础。
[Abstract]:Beidou Navigation system is a self-developed navigation and positioning system in China. When completed, it can provide navigation and positioning services to global users. After the GPS of the United States and GLONASS of Russia, rare's navigation and positioning system. Beidou navigation system has played a great role in many fields of national production and life. Carrier phase observation is an important observation in navigation system, and it is widely used. Cycle slip problem is also a unique problem in carrier phase application technology. The existence of cycle slip affects the accuracy of Beidou navigation and positioning. It is necessary to ensure the "clean" of the observed values when using the carrier phase observations in high precision positioning. Therefore, the cycle slip detection and repair is a very important work in the use of carrier phase observations. Firstly, this paper introduces the Beidou guide. The current development of the navigation system, Starting with the use of carrier phase observations, the cycle slip problem in carrier observations is introduced. The signal characteristics, basic observations and their linear combinations of Beidou navigation system are expounded. The errors existing in navigation and positioning and the methods to deal with them. The basic theory of cycle slip, such as the definition and the causes, the influence of the error on the positioning accuracy, are expounded. The structure of detecting cycle slip is compared and analyzed, and their advantages and disadvantages are summarized. Finally, double difference detection is chosen as the cycle slip detection in this paper. Secondly, Based on the GPS cycle slip detection and repair method, this paper analyzes the current application of wavelet transform in cycle slip detection and repair. Wavelet transform is often used to detect cycle slip instead of cycle slip repair. In this paper, the wavelet transform method is studied, and the method of detecting cycle slip and repairing cycle slip directly by wavelet transform method is put forward. The basic principle of this method is to decompose the detection sequence by wavelet transform. The sequence without cycle hopping is smooth, if the singular value of the high frequency coefficient appears after decomposition, the existence of cycle slip is indicated. For the interpolation substitution of singular value, the combination of the high frequency coefficient and the low frequency coefficient after the replacement is used to reconstruct the signal, which is different from the original signal. By detecting the sequence after repair, if the high frequency coefficient still exists singular value, continue to replace the repair. Repeat the above steps until the high frequency coefficient no longer have singular value, That is, complete cycle slip repair. Beidou system has a geostationary orbit satellite, which is not found in the GPS system, which has a great influence on the observational values. Therefore, this uniqueness of Beidou is fully taken into account in the construction of double difference detection. Finally, In this paper, the effectiveness of the proposed method is verified by a concrete example analysis, and the wavelet transform can directly repair the cycle slip. At the same time, the shortcomings of the method are found, that is, the repair process is completed one by one. The work done and the results obtained in this paper are summarized. To lay the foundation for the related research.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P228.4

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