【作者】 李玮；

【导师】 程鹏飞； 秘金钟；

【作者基本信息】 中国测绘科学研究院 ， 大地测量学与测量工程， 2010， 硕士

【摘要】 GPS精密单点定位是利用IGS提供的精密卫星星历和钟差产品,以单台双频GPS接收机的伪距和载波相位观测值来进行精密绝对定位的方法。其定位精度可达到静态厘米级和动态分米级的水平。除位置外,还可同时得到接收机钟差、对流层天顶延迟等产品,使得该技术在坐标框架的维持、高精度导航定位、大气延迟提取及精密授时等领域均具有广阔的应用前景。本文系统研究了精密单点定位理论,着重分析了相关的技术难点,对部分关键问题,如参数估计、误差随机模型确定、实时质量控制等进行了详细论述。主要研究内容包括以下几方面:1、精密单点定位观测方程及其误差源在GPS原始观测方程的基础上,推导了无电离层组合和非组合两种精密单点定位方法的观测方程;详细阐述了精密单点定位过程中影响显著的误差源及相应的处理方案。2、两种精密单点定位方法:参数估计策略及结果分析介绍了两种精密单点定位方法的数学模型、未知参数的估计方案和随机模型,并比较了两种精密单点定位方法的优缺点,分别利用随机游走过程模拟对流层残差随机变化和白噪声过程描述钟差随机变化。分别对静态,仿动态,以及船载低动态数据和机载高动态数据进行处理,表明作者研发的PPP软件能达到较高的精度,在静动态条件下分别能达到厘米级和分米级的定位精度,滤波收敛后定位结果的稳定性可分别达到1～3厘米和6～10厘米。该精度与国内外同类的研究结果相当。首次实验分析了两种PPP算法,比较了各自的特点以及在定位中的应用,实验结果表明,非组合PPP不仅能够有效减少各坐标分量解得滤波收敛时间,且滤波收敛解的稳定性也得到改善。3、精密单点定位的实时质量控制提出GPS精密单点定位的实时质量控制,并将基于预报残差的DIA质量控制过程引入到PPP定位中,通过实例证明:实施DIA质量控制后能加快滤波收敛速度,并提高精密单点定位解的稳定性和精度,实施DIA质量控制策略以后,各坐标分量经过约35分钟即可收敛到1分米以内,且收敛后X、Y、Z三分量的外符合精度可分别达到2、2、4厘米。4、GPS精密单点定位的其他应用利用静态精密单点定位技术,估计得到单站对流层天顶延迟和接收机钟差,通过与IGS发布的最终产品进行比较,分析了其精度。利用IGS跟踪站进行试验,试验结果表明,利用精密单点定位方法,基于单站24小时的双频观测数据,可估计得到无明显系统偏差、精度达毫米级的绝对天顶对流层延迟和实现0.1～0.3ns的时间传递精度,进而拓展了精密单点定位技术的应用范围。更多还原

【Abstract】 Precise Point Positioning (PPP) is a positioning technique using dual-frequency pseudorange and carrier phase observations from a stand-alone GNSS receiver along with the precise orbit and clock solutions published by IGS, one can determine the position of anywhere in the global area with a high precision, decimeter even centimeter. Besides the position, the receive clock corrections, Zenith Troposphere Delays (ZTDs) and float ambiguity estimates could also be obtained with this technique, which broaden applications of PPP techniches in the field of high-precision navigation and positioning, atmosphere delays’determination, precise time and frequency transfer etc.PPP technique and some key problems are discussed in this paper, including parameter estimations, stochastic model determinations, quality control, etc. The main contents and conclusions of this paper are as follows:1. The observation equations of PPP technique and its systematic errorsBased on original dual-frequency GPS code and phase observations, the observation equations of ionosphere-free combination and uncombined PPP techniques are deduced. Several corrections to the systematic errors existing in the measurements, such as relativistic effects, phase wind-up etc, are also presented.2. Two PPP techniques, including parameter estimation strategy and result analysisTwo PPP techniques are introduced, including their math models, unknown parameter estimation strategy and stochastic models. The advantages and disadvantages of each PPP technique are also discussed. Under different conditions such as static, simulated kinematic, low-dynamic offshore and high-dynamic airborne data, the overall performances of PPP techniques are investigated and analyzed. The results show that for both static and kinematic positioning, a position accuracy of 1～3 cm and 6～10 cm could be achieved with the author’s PPP software.The positioning performances of two PPP techniques are compared for the first time. The results show that the convergence behavior and repeatability of filtered solutions can be well improved by comparing the uncombined PPP technique with the traditional one.3. Real time quality control of PPP techniqueReal time quality control of GPS PPP technique is proposed, the recursive DIA-procedure is adopted as quality control strategy to guarantee the reliability of the estimators from PPP technique. The results show that convergence behavior and repeatability of filtered solutions can be well improved after DIA-procedure.4. Some other applications of GPS PPP techniqueThe receive clock corrections and ZTDs can also be obtained with PPP technique, their accuracy are analyzed by comparing with corresponding IGS products. The results show that, based on dual-frequency observations of single station, one can realize millimeter accuracy without systematic bias in ZTDs’determination and 0.1～0.3ns accuracy in time transfer, which demonstrate the wide applications of PPP implementation.更多还原