GNSS精密单点定位算法研究与实现

发布时间：2018-10-26 22:05

【摘要】：高精度GNSS单点定位是空间测量技术的热点，GNSS精密单点定位（PPP）数据处理模型的不断完善使其在测绘等各个领域得到广泛应用，但其周跳探测及修复和模糊度解算两大关键问题仍存在不足。本文研究GNSS PPP的周跳探测及修复和模糊度解算的新方法，并自主开发GNSS PPP软件以验证提出的新方法的可靠性和有效性，主要研究内容如下： 1）精密单点定位与差分定位主要区别之一在于精密单点定位需要对更多的误差源进行改正。本文首先分析了GNSS PPP各项误差特性及其对解算精度的影响机理，给出了各项误差源的量级。通过不同模型实验结果对比，确定最优改正模型，以提高GNSS PPP导航定位精度； 2）数据预处理方法直接影响卡尔曼滤波的收敛速度和GNSS PPP的解算精度与可靠性，周跳探测及修复是其关键问题之一。研究GNSS PPP非差观测值周跳探测及修复问题，提出基于经验模态分解（EMD）异常值检测的周跳探测方法。该方法分析观测信息的信号特征及信号的异常值特性，通过检测信号的异常值判断周跳发生的位置与大小，并通过实例验证该方法的适用性； 3）研究了TECR/M-W组合周跳探测及修复算法，针对电子含量变化率（TECR）无法准确探测采样间隔较大（如30s）数据周跳的问题，提出利用TECR预测值与实测值的残差作为检验量进行周跳探测方法，消除TECR算法中时间项的影响。实验结果表明：改进的TECR/M-W组合周跳探测及修复算法充分利用两种算法的优点，提高了周跳探测及修复效率，对任意采样间隔、大小和不同组合的周跳均能有效探测并修复； 4）介绍了目前常用的PPP模糊度解算方法，在此基础上通过推导浮点模糊度、宽巷组合模糊度与窄巷模糊度三者之间关系，提出无基站PPP模糊度解算方法。利用SOPAC提供的ITRF坐标以及GAMIT解算结果作为真值，对全球IGS站数据与实测数据解算结果与之对比，验证提出的无基站PPP模糊度解算方法的解算精度和可靠性。实验结果表明：提出的PPP模糊度算法在定位精度和与参考坐标的绝对偏差上相对于浮点解都有明显提高； 5）研究GLONASS与GPS数据处理差异，分析GPS/GLONASS PPP与GPSPPP的区别，建立了GPS/GLONASS PPP解算模型。实验结果表明GPS/GLONASS组合定位可以优化卫星分布，在GPS卫星较少时提高PPP适用性，但受制于GLONASS精密星历和钟差的精度影响，GPS/GLONASS PPP的定位精度相对于GPS PPP并没有得到明显提高； 6）自主开发GNSS PPP软件，实现GPS PPP、GNSS PPP的浮点解和固定解两种解算模式，，验证提出的非差观测值周跳探测及修复和无基站模糊度算法的有效性和准确性。
[Abstract]:High precision GNSS single point positioning is a hot spot in spatial measurement technology. With the improvement of (PPP) data processing model of GNSS precise single point positioning, it has been widely used in many fields, such as surveying and mapping. However, its cycle slip detection and restoration and ambiguity resolution are still two key problems. In this paper, a new method of cycle slip detection and restoration and ambiguity resolution of GNSS PPP is studied, and GNSS PPP software is developed to verify the reliability and effectiveness of the proposed method. The main research contents are as follows: 1) one of the main differences between precision single point positioning and differential positioning is that precision single point positioning needs to correct more error sources. In this paper, the error characteristics of GNSS PPP and its influence mechanism on the accuracy of solution are analyzed, and the order of magnitude of each error source is given. By comparing the experimental results of different models, the optimal correction model is determined to improve the accuracy of GNSS PPP navigation and positioning. 2) the data preprocessing method directly affects the convergence rate of Kalman filter and the accuracy and reliability of GNSS PPP. Cycle slip detection and repair is one of its key problems. In this paper, the problem of cycle slip detection and repair of GNSS PPP nondifferential observations is studied, and a cycle slip detection method based on empirical mode decomposition (EMD) (EMD) outliers detection is proposed. This method analyzes the signal characteristics of the observation information and the abnormal value characteristics of the signal, judges the position and size of the cycle slip by detecting the abnormal value of the signal, and verifies the applicability of the method by an example. 3) the combined cycle slip detection and repair algorithm of TECR/M-W is studied. Aiming at the problem that the electronic content change rate (TECR) can not accurately detect the cycle slip of data with large sampling interval (such as 30s), In order to eliminate the influence of time term in TECR algorithm, a cycle slip detection method based on the residual of TECR prediction value and measured value is proposed. The experimental results show that the improved TECR/M-W combined cycle slip detection and repair algorithm makes full use of the advantages of the two algorithms and improves the efficiency of cycle slip detection and repair. The cycle slips of different sizes and combinations can be detected and repaired effectively. 4) this paper introduces the PPP ambiguity calculation method which is commonly used at present. On this basis, by deducing the relationship among floating-point ambiguity, wide-lane combination ambiguity and narrow roadway ambiguity, a method for calculating PPP ambiguity without base station is put forward. Using the ITRF coordinates provided by SOPAC and the results of GAMIT as the true values, the accuracy and reliability of the proposed PPP ambiguity resolution method without base station are verified by comparing the global IGS station data with the measured data. The experimental results show that the proposed PPP ambiguity algorithm can improve the positioning accuracy and the absolute deviation from the reference coordinates obviously compared with the floating point solution. 5) the difference between GLONASS and GPS data processing is studied, the difference between GPS/GLONASS PPP and GPSPPP is analyzed, and the GPS/GLONASS PPP solution model is established. The experimental results show that GPS/GLONASS combined positioning can optimize the satellite distribution and improve the applicability of PPP when the GPS satellite is less, but it is limited by the precision of GLONASS precise ephemeris and clock error. The positioning accuracy of GPS/GLONASS PPP is not obviously improved compared with GPS PPP. 6) GNSS PPP software is developed independently to realize the floating-point solution and fixed solution of GPS PPP,GNSS PPP. The validity and accuracy of the proposed algorithm for detecting and repairing cycle slips and ambiguity without base station are verified.
【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：P228.4

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