精密单点定位理论与方法研究

发布时间：2018-07-07 15:52

本文选题：卫星导航系统 + 精密单点定位　；参考：《国防科学技术大学》2015年博士论文

【摘要】：精密单点定位(PPP)集成了标准单点定位和差分定位的优点,利用全球若干跟踪站观测数据计算得到的精密星历和钟差,对单台接收机测量的相位和伪距观测值进行非差数据处理,能达到厘米级的定位精度。目前,精密单点定位面临的主要挑战是其相对较长的初始化时间,通常需要20分钟以上的时间才能使浮点解收敛到厘米级的定位精度,限制了其实时应用。快速确定非差整周模糊度,加快精密单点定位收敛速度,能大大改进精密单点定位的性能,使其得到更广泛的应用。在此背景下,本文从非差模糊度整数特性恢复、电离层延迟提取以及伪距多径误差消除三方面着手,进行了如下研究:(1)根据接收机载波相位测量原理分析了接收机载波小数相位偏差的形成机理及变化特性。理论分析与实验数据表明,小数相位偏差具有长期稳定性,与信号失锁和本地时间调整无关,其开机特性与开机时本地时刻整秒对应的射频本振的相位有关。在接收机设计上可以采用整数倍频法、相位再同步、射频采样等方案来避免接收机小数相位偏差的开机变化。(2)提出一种利用参考站网络估计卫星和接收机小数相位偏差的改进方法。其中宽巷模糊度的获取采用非组合PPP估计得到的双频原始模糊度作差得到,与传统利用Melbourne-Wubbena组合观测值确定宽巷模糊度方法相比,宽巷小数相位偏差的估计精度提高了10%。此外,非组合PPP中将垂向电离层延迟而非斜向电离层延迟作为参数估计,宽巷小数相位偏差的估计精度改善了6%。最后应用参考站估计的小数相位偏差改正进行了模糊度解算,固定解与浮点解相比定位精度有明显提高,其中东向误差改进最显著(约41%)。(3)改进了利用双频PPP提取高精度电离层延迟的方法。为避免建模误差,不采用电离层薄层模型分离差分码偏差,而通过星间单差消除接收机差分码偏差的影响。此外,利用区域参考网估计的小数相位偏差改正修正非差模糊度小数部分,然后进行模糊度解算。模糊度固定后,双频PPP电离层延迟提取的单天平均精度由浮点解的3.84cm提高到模糊度固定解的1.46cm。(4)提出了利用单频PPP加密双频提取星间单差电离层延迟的方法。对单频观测量进行对流层延迟改正、小数相位偏差改正及恒星日滤波伪距多径消除后,可以利用星间单差伪距-相位无电离层组合观测量来固定单频星间单差载波相位模糊度,从而得到基于相位观测值的星间单差电离层延迟。理论分析与实验表明,模糊度固定后,单频PPP提取星间单差电离层延迟单天平均精度达1.74cm,与双频PPP法精度相当。从而可以利用单频接收机来加密区域电离层辅助参考网,减少网络布设成本。(5)针对卫星轨道周期的差异,提出了基于卫星视角(仰角和方位角)的恒星日滤波方法,对每颗卫星每个历元根据视角目标函数确定恒星日滤波的周期,精细了传统恒星日滤波方法,有效消除了伪距多径误差。本文应用恒星日滤波方法改进了实时电离层延迟提取精度和准静态站的动态定位精度,其中实时电离层提取单天误差的平均值从0.185m降为0.028m,动态定位精度东北天方向分别提高了69.2%、72.3%、27.6%,验证了该算法的有效性。
[Abstract]:The precision single point positioning (PPP) integrates the advantages of standard single point positioning and differential positioning. The precise ephemeris and clock difference calculated from the observational data of several tracking stations in the world are used to process the phase and pseudo range observations measured by a single receiver, which can reach the centimeter level positioning accuracy. At present, the precision single point positioning is facing the main position. In order to challenge its relatively long initialization time, it usually takes more than 20 minutes to make the floating-point solution converge to the centimeter level positioning accuracy and limit the actual time application. It can quickly determine the non differential integer ambiguity and speed up the convergence speed of the precise single point positioning, and can greatly improve the performance of the precise single point positioning. In this context, the following studies are carried out from the following three aspects: the restoration of the integer characteristic of the non differential ambiguity, the extraction of the ionosphere delay and the elimination of the pseudo range multipath error. (1) the formation mechanism and the change characteristics of the carrier phase deviation of the receiver carrier are analyzed according to the principle of carrier phase measurement of the receiver. It is not related to the signal locking and local time adjustment, and its opening characteristic is related to the phase of the radio frequency local oscillator corresponding to the local moment at the local time. The receiver design can use the integer doubling, phase resynchronization and RF sampling to avoid the opening of the receiver decimal phase deviation. (2) (2) an improved method of estimating the phase deviation of the decimal fraction of the satellite and the receiver by using the network of reference stations is proposed. The acquisition of the width of the width of the wide lane is obtained by using the original ambiguity of the dual frequency obtained by the non combinatorial estimation. Compared with the traditional method of determining the width of the width of the wide alley with the traditional combination observation value, the width of the width of the wide alley is obtained. The estimation accuracy of the bit deviation is improved by 10%.. The vertical ionospheric delay and not the oblique ionospheric delay are used as parameter estimation in the non composite PPP. The estimation accuracy of the small number phase deviation in the wide lane is improved by 6%.. The resolution of the decimal phase deviation correction in the reference station is calculated. The fixed solution is compared with the floating point solution. The east direction error is improved significantly (about 41%). (3) the method of extracting high precision ionospheric delay using dual frequency PPP is improved. In order to avoid modeling error, the difference code deviation is separated from the ionospheric thin layer model, and the difference of the differential code of the receiver is eliminated by the single difference between the stars. In addition, the regional reference network is used to estimate the difference. The decimal phase deviation correction corrects the fractional part of the non difference ambiguity and then calculates the ambiguity. After the fuzzy degree is fixed, the single day average precision of the double frequency PPP ionospheric delay extraction is raised from the floating point 3.84cm to the 1.46cm. (4) of the fuzzy degree fixed solution. The method is proposed to extract the INTERSTAR single difference ionospheric delay by single frequency PPP encrypted double frequency. The single frequency measurement for tropospheric delay correction, decimal phase deviation correction and stellar diurnal filtering pseudo range multipath elimination can be used to fix the single difference carrier phase ambiguity between single frequency satellites using the INTERSTAR single difference pseudo range and phase unionospheric combination view, thus obtaining the INTERSTAR single difference ionospheric delay based on the phase values. The experiment shows that the single frequency PPP extraction of single frequency single difference ionospheric delay is 1.74cm and the accuracy is equal to the double frequency PPP method. The single frequency receiver can be used to encrypt the regional ionospheric auxiliary reference network and reduce the network layout cost. (5) in view of the difference of the satellite orbit cycle, the satellite angle of view (elevation angle) is proposed. The method of stellar daily filtering is used to determine the period of Star daily filtering for each satellite based on the target function of the angle of view. The traditional star day filtering method is fine. The pseudo range multipath error is eliminated effectively. This paper uses the star day filtering method to improve the precision of the real-time ionization layer delay extraction and the dynamic positioning precision of the quasi static station. The average value of the real-time ionospheric extraction single day error is reduced from 0.185m to 0.028m, and the dynamic positioning accuracy is increased by 69.2%, 72.3%, and 27.6% respectively. The validity of the algorithm is verified.
【学位授予单位】：国防科学技术大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：P228.4

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