【作者】 吕志伟；

【导师】 郝金明；

【作者基本信息】 解放军信息工程大学 ， 大地测量学与测量工程， 2010， 博士

【摘要】 基于连续运行基准站的动态定位技术也称为网络动态定位技术、多基准站动态定位技术,是近年来在常规动态定位、通讯、网络、计算机等技术的基础上发展起来的一种高精度动态定位新技术,是卫星导航定位技术的发展趋势之一。本文系统地研究了基于连续运行基准站的动态定位理论,设计并编程实现了基于连续运行基准站的动态定位的核心算法,通过大量算例验证了本文所涉及理论与方法的正确性。本文的主要工作和创新点概括如下:1、研究和归纳了卫星定位的观测模型、误差模型和随机模型。给出了基本观测量和组合观测量的观测方程、线性化方程,分析了常用组合观测量的特点。分析了卫星相对定位中系统误差和偶然误差的定义、特性、影响量以及常用的改正方法。系统误差包括卫星星历误差、电离层延迟、对流层延迟;偶然误差包括多路径效应、观测噪声。推导了形式简单明了、用单差矩阵表示的观测量随机模型。2、研究了基于连续运行基准站的动态定位的数学模型。把动态定位计算分成了三个主要步骤:基准站间的基线解算、虚拟参考站观测数据的构建和流动站用户的定位计算。中长距离基线的模糊度解算、误差改正数据的内插算法是动态定位的关键。在此基础上,改进了常见的动态定位数学模型:一是将综合误差处理改进成与卫星相关的站间单差电离层延迟、与基准站相关的对流层延迟,这样处理有利于不同物理性质的分离和精化处理,有利于后续虚拟参考站观测数据的构建;二是将双差整周模糊度参数分成了两个站间单差模糊度,这样处理有利于流动站用户定位解算切换参考星时更顺畅,使得定位结果更连续性。不过这种改进数学模型会增加待估参数的数量。3、研究了GNSS观测数据的周跳探测与修复。在分析了几种较实用方法的基础上,设计了适用于动态定位的周跳探测与修复方法:电离层残差和TurboEdit组合法,并分析了方法的探测精度、适用性、可靠性。用基准站数据的算例表明该方法能够探测并修复0.5周以上的周跳。4、研究了基准站观测数据的质量分析方法。GNSS观测中的观测噪声和多路径效应属偶然误差,对定位质量的影响不能忽略,但不易分离。针对这一问题,设计了一种接收机观测噪声分析的实验方法,推导了接收机观测噪声估计的数学模型,算例也表明:接收机的噪声大小与高度角相关,伪距观测噪声和载波相位观测量噪声有一定比例关系。提出了一种载波相位观测量多路径效应的分析方法,设计了实验方法,推导了多路径的解算模型。用实际观测数据比较了不同类型观测量、不同频点的观测量多路径效应的异同,分析了多路径效应与卫星高度角的关系。5、本文使用Kalman滤波作为动态定位的参数估计方法,推导了Kalman滤波用于动态定位数据处理的数学模型,并顾及观测模型是非线性模型、待估参数常常发生变化给出了解决方法。将Kalman前向滤波和双向滤波应用到基于连续运行基准站的动态定位中,前向滤波可用于实时定位应用,后者可用于事后的高精度应用。通过算例比较了前向滤波和双向滤波的性能。提出了一种顾及基准站已知坐标的参数估计方法,这种方法在参数估计时固定基准站的坐标。算例表明该方法在中长距离基准站相对定位数据处理时能够提高整周模糊度解算成功率和固定解比例,验证了方法的正确性和有效性。还对算法的适应性进行了比较分析。6、本文将整周模糊度解算分成了两个主要步骤:模糊度的实数估计和整周模糊度的搜索。介绍了常用的整周模糊度搜索方法,并分析了各种方法的特点。考虑到LAMBDA方法在数学上更严密,充分利用了方差协方差阵提供的信息,能够提供整周模糊度的最优无偏估计,并且优化了搜索空间,能偶提高搜索效率,本文采用了LAMBDA方法进行模糊度搜索,RATIO值进行模糊度确认。7、将虚拟参考站的观测量构建分成基准站间电离层延迟与对流层延迟估计、虚拟参考站处误差内插两个主要步骤。分析了电离层延迟、对流层延迟估计的确定性模型和随机性模型,提出了一种考虑观测量残差的? 2检验的整周模糊度固定方法。算例表明,该方法能够解决卫星观测数目变化等原因导致的整周模糊度的固定情况发生变化时,所估计的电离层延迟和对流层延迟出现不连续的情况。比较分析了虚拟参考站处误差内插的常用方法。算例表明:电离层延迟内插值和参数估计值的最大差值为2厘米,对流层延迟的最大差值为0.8厘米,验证了电离层延迟、对流层延迟估计算法以及内插算法的正确性。8、推导了流动站用户动态定位的数学模型,比较分析了基准站间定位与流动站用户动态定位在应用需求、观测条件、观测模型和动态模型等方面的异同。编程实现了流动站用户定位解算,用不同载体、不同距离的动态定位算例,验证了本文采用的流动站动态定位数学模型的正确性。9、结合不同载体观测数据的特点,分析了动态定位中的多种数据处理策略。研究了数据采样率和载体动态性能的相互关系,建议中低动态用户定位的数据处理可考虑适当降低数据的间隔;比较了单双频数据定位结果,对于观测条件好的中低动态用户,用单频接收机代替双频接收机也能达到厘米级定位精度;研究了基准站和流动站高差较大时的动态定位结果,距离较远时或高差较大都应估计对流层延迟影响;研究分析了不同解算模式对定位结果的影响,动态定位数据处理应尽量减少未知量的个数,有利于提高解的成功率和固定解的比率。更多还原

【Abstract】 Technology based on continuously operating reference stations is also known as network real-time kinematic positioning technology or multi-reference stations kinematic positioning technology, which is a new high-precision kinematic positioning technologies based on other technologies such as conventional kinematic positioning, communications, networking and computers in recent years. Network real-time kinematic technology is one of the trends of the satellite navigation and positioning technology development. This thesis systematically studies the kinematic positioning and programs the algorithm based on continuously operating reference stations. Extensive example results verify that the theories and methods involved in this thesis are correct. the main work and innovation are summarized as follows:1、The observation model, the error model and the stochastic model for satellite positioning are studied and summarized. The observation equation and linear equation of raw observation data and their combinations were given and the characteristics of some commonly used combinations are analyzed. The definition, characteristics, affect value and correction of systematic errors and accidental errors in satellite relative positioning are analyzed. The systematic errors include satellite ephemeris error, ionospheric delay, tropospheric delay; accidental errors include multi-path effect, observation noise. The observation stochastic model with simple form using the single-difference matrix is derived.2、The mathematical model of dynamic positioning based on continuously operating base station is studied. The dynamic positioning calculation is divided into three main processes: baseline solution between base stations, constructing observation data of the virtual reference station and positioning calculation of moving station users. The ambiguity resolution of medium-to long-range baseline and the interpolation algorithm of error correction data are two vital factors of dynamic positioning. On this basis, the common mathematical model of dynamic positioning has been improved: First, the synthesis error processing has been improved into the single-difference Ionosphere delay between stations related to satellites and the troposphere delay related to base station. It is beneficial to separate and refine different physical properties and construct successive observation data of virtual reference station; second, double-difference ambiguity parameters has been changed into single-difference ambiguity between two stations. It is beneficial that positioning calculation of moving station users become smoother when switching reference satellite so that the positioning result become more continuous. However, this improved mathematical model will increase the number of parameters to be estimated. 3、This thesis analyses the cycle-slip detection and repair of GNSS observation data. Analyzed several practical methods the combination method using ionosphere residual error and TurboEdit is designed for cycle-slip detection and repair of kinematic positioning. Accuracy, applicability, and dependability of this method are analyzed. The example with reference station data shows that this method can detect and repair cycle-slip more than 0.5 cycle.4、The analysis method of the quality of reference stations observation data is studied. The observation noise and multi-path effect of GNSS observation belong to accidental errors, the influence of which on positioning can not be neglected but hard to be separated. To solve this problem, a experimental method of receiver noise analysis is designed, and the mathematical model of receiver noise estimation is derived, the example results show: The magnitude of the receiver noise is related to the elevation angle. Pseudo-range observation noise and carrier phase observation noise have a relationship of certain percentage. An analysis method of carrier-phase measurement multi-path effects is proposed. The experimental method is designed, and multi-path solution model is deduced. Actual observation data is used to analyze the difference and relation of multi-path effects among different types of measurement or measurement at different frequency points, the relation between multi-path effects and satellite elevation angle is analyzed.5、This thesis uses the Kalman filter as a kinematic positioning parameter estimation method, and derives the mathematical model of Kalman filter used for kinematic positioning data processing, furthermore, gives the solution though the observation model is non-linear and the estimated parameters change frequently. Next, the forward and the bi-directional filter are applied in kinematic positioning based on continuously operating reference stations, the former one can be used for real-time positioning and the latter can be used for high-precision applications. The performance of the forward filter and the bi-directional filter are compared by the results of calculative experiments. The parameter estimation method taking the known coordinates of base station into account is proposed which fix the base station coordinates when parameters are estimated. The results show that this method can improve the success rat of the ambiguity solution and the proportion of the fixed solution in the relative positioning data processing of the medium and long distance, and this method is correct and valid. Besides, the adaptability of this algorithm is analyzed in this thesis.6、In this paper ambiguity solution is divided into two main steps: a real ambiguity estimation and integer ambiguity search. The common integer ambiguity search method are described. and the characteristics of various methods are analyzed. Taking into account that the LAMBDA method is more mathematically rigorous, takes full advantage of the variance-covariance matrix, provides information to provide the optimal Ambiguity unbiased estimate,and optimize the search space and can even improve the search efficiency, this paper adopts the LAMBDA method in ambiguity search and RATIO value as a confirmation.7、Building measurement of virtual reference station consist of two main steps. One is estimation of ionospheric and tropospheric delays,the other is error interpolation (of virtual reference station) . Deterministic model as well as stochastic model of ionospheric and tropospheric delays are analyzed, and then a procedure considering ? 2testing residuals of observables for ambiguity fixation is proposed. Experimental result indicated that when changes of tracked satellite number cause conditions of ambiguity fixing change,this procedure can solve the uncontinuous estimation of ionospheric and tropospheric delays.Experimental result indicated that the maximum difference between interpolation of ionospheric delay and parameter estimates is 2 cm. For tropospheric delays, this difference is 0.8. In experiment, the ionospheric and tropospheric delay estimation algorithms as well as interpolation algorithm are verified to be correct.8、The mathematic model is derived. The differences between base stations relative positioning and rover user kinematic positioning are compared and analyzed in application requirement, observational condition, observation model and kinematic model. The solution program of rover user positioning is made. And then the mathematic model of rover user kinematic positioning is validated through the example of kinematic positioning with regard to different vehicle and different distances.9、Considering the characteristic of observational data of different carriers, numbers of data proceeding strategies are analyzed in kinematic positioning. The correlation between data sampling rate and vehicle dynamic performance, and reducing data interval is proposed in data proceeding of moderate and low user kinematic positioning. The positioning results of single and dual frequency data are compared, and to moderate and low kinematic user in the good observational condition, the accuracy of centimeter is reached if dual-frequency receiver is replaced by single-frequency receiver. The kinematic positioning results are researched when the height difference between base station and rover station are too large, and the tropospheric delay must be estimated when the distance is too far or height difference is to large. The effects to positioning results of different resolution mode are researched and analyzed. The number of unknown quantity should be reduced in kinematic data proceeding, that is beneficial to advance success rate of solution and fixed solution.更多还原