【作者】 徐维梅；

【导师】 卢秀山； 郑作亚；

【作者基本信息】 山东科技大学 ， 大地测量学与测量工程， 2009， 硕士

【摘要】 GPS精密单点定位技术利用IGS精密星历和卫星钟差,以单台接收机采集的非差相位观测数据在全球范围内静态或动态独立作业,并且直接得到高精度的ITRF框架坐标。因此,它在高精度的坐标框架维持、区域性或全球性的科学考察、低轨卫星定轨及海岛(礁)测图等方面都具有不可估量的前景,是今后GPS研究的热点之一。在GPS精密单点定位中,GPS卫星钟差是影响定位精度的主要因素之一,由于GPS原子钟频率高,非常敏感,极易受到外界及其本身因素的影响,从而很难掌握其复杂细致的变化规律,如何提高GPS卫星钟差的加密及预报精度成为GPS精密单点定位急需解决的关键问题之一。针对这一问题,本文提出了在精密单点定位中GPS卫星钟差内插方法、预报模型及其精度分析的研究。本文首先简要介绍了精密单点定位的特点和发展现状,分析了精密单点定位中获取实时高精度的卫星钟差的重要性。在此基础上,分析了GPS非差精密单点定位的原理、GPS非差观测模型、误差改正模型和非差精密单点定位的关键技术问题。论文主要研究内容分为两部分,首先是对卫星钟差内插的研究,详细叙述了六种常用内插拟合算法的原理,并编程实现各种算法,通过算例对载有不同钟类型(铷、铯)卫星的钟差内插结果进行了比较,分析了各种算法的特点和优劣得出,对存在很大抖动的卫星钟钟差,三次样条插值的内插效果最稳定;然后是对卫星钟差预报方面的研究,主要阐述了线性模型、二阶多项式模型、灰色模型和狄色残差模型、二次多项式+周期项模型等各种预报模型的原理及公式推导,并编程实现各种算法,通过算例和大量数据分析对各种模型和方法的钟差预报精度进行了比较分析,其中尝试研究了递推遗忘因子最小二乘算法作为钟差预报模型的预报精度,分析了各种模型的特点和适用性,灰色模型和灰色残差模型适宜对钟差变化不稳定的钟差进行较长时间的预报,而二次多项式+周期项模型和递推遗忘因子最小二乘算法较适合对变化稳定的卫星钟差进行短时间预报。更多还原

【Abstract】 Precise Point Positioning(PPP) uses un-differenced pseudorange and carrier phase observations along with IGS precise orbit and satellite clock bias,for stand-alone precise geodetic point positioning(static or kinematic) and to get the high precise ITRF coordinates directly.It plays a very important role in accessing the terrestrial reference frame,regional or global scientific expedition,LEO’s orbit determination,and surveying and mapping of island. Also it is one of the key techniques to be studied in the future.In the PPP methods,it needs to overcome several key technical problems.Due to the high frequency and high sensitivity of GPS atomic clocks and the impact of external or its own factors,how to interpolate and predict high quality GPS satellite clock bias becomes one of the key technical problems.In response, this paper mainly makes a study on the interpolation methods and prediction models of PPP.In this paper,it firstly describes the PPP approach and its development status at home and abroad,the importance of solving how to get the high quality real-time GPS satellite clock bias.Then it discusses the theory of the PPP,GPS un-differential model,its error correcting model,and its key technique.The paper analyzes the main problem in two parts.Firstly,it introduces six popular interpolation methods in details,and has programmed processing procedure of these algorithms.And it has made much experiment to compare the interpolation results of satellite clock bias from two different atomic clocks(Rb or Cs),and analyze the features and merits of these algorithms.The results show spline interpolation is the best. Secondly,it discusses the principles and formulas of five algorithms:linear model,quadratic polynomial model,grey model and grey residual model,quadratic polynomial+periodic function model,and the recursive forgetting factor least squares method.And it has made much experiment to compare and analyze the prediction precision of satellite clock bias from two atomic clocks(Rb or Cs),and analyze the features and applicability of these models.It shows that grey model and grey residual model are useful for the little longer time prediction. Quadratic polynomial+periodic function model and recursive forgetting factor least squares method are suitable for short time prediction for satellite clock bias of stability changes.更多还原