【作者】 姚宜斌；

【导师】 刘经南； 陶本藻；

【作者基本信息】 武汉大学 ， 大地测量学与测量工程， 2004， 博士

【摘要】 卫星精密定轨是卫星对地观测技术发展和应用的基础,没有先进的定轨技术和相应的软件保证获得高精度轨道,就不可能进行精密定位和开拓其它领域的应用。我国卫星定位技术的应用已有20多年的历史,但是目前卫星精密定轨、定位软件还主要依靠引进的软件,这种依赖国外软件的状况很难取得突破性的创新成果。只依靠国外软件已无法满足我国快速发展的卫星计划的实际需要,也不利于国防安全的保障,所以应尽快开发具有我国特色和自主知识产权的卫星精密定位定轨软件系统。 卫星精密定位定轨研究实际包含两部分的内容,一部分是利用原始观测数据进行地面站间基线单天解和单天轨道确定;另一部分是后处理部分,即利用单天解的轨道和基线处理结果进行多种参数联合估计和轨道综合。高精度定位定轨后处理的数据源包括轨道参数、各类地球动力学模型参数、站坐标参数、站速度参数、对流层参数、整周模糊度参数乃至卫星和接收机参数等,各类参数具有复杂的函数相关性和误差相关性,处理起来比较复杂。 本文研究的内容主要涉及卫星精密定位定轨研究的后处理部分,主要是研究利用单天解的轨道和基线处理结果进行多类参数(测站坐标参数、测站速度参数、地球自转参数、定轨参数等)的联合估计和轨道综合问题,在此领域国内尚没有开展系统性的研究。本论文研究的成果和内容具体包括: (1)提出利用SINEX(Solution INdependent EXchange Format)文件作为GPS精密定位定轨后处理的主要输入文件,讨论了SINEX文件结构及其与法方程的相互转换问题。SINEX文件作为数据解文件的标准格式,包含GPS、VLBI、SLR等所提供的基线解算或者是网平差后的点位坐标、点位协方差、点位先验坐标、点位先验方差信息,可以通过SINEX文件恢复法方程,通过法方程叠加实现多期、多类、多子网数据的联合处理。 (2)在分析基于基线模式的常用的GPS网平差模型的基础上,提出直接以所涉及的测站坐标信息、地球自转参数信息等为观测量的基于坐标模式的广义网平差模型。分析了基于基线模式和基于坐标模式的模型之间的相互联系和区别,总结了基于坐更多还原

【Abstract】 Satellite precise orbit determination(POD) play a very important role in Earth Observing System (EOS). Precise positioning can’t be done without advanced POD technique and software, which ensure to achieve the accurate orbit of satellite. In the past twenty years, the technology of satellite positioning has been widely developed and applied in china. But the software of precise orbit determination and precise positioning we used always comes from foreign country. Such situation will impede us to make outstanding and creative achievement. Just relying on the imported software can’t meet the practical need of developing the satellite plan in our country, and also make against national defense safety guarantee. In a word, we should develop the satellite precise orbit determination and precise positioning software with our own property and characteristic as soon as possible.Research on satellite precise positioning and orbit determination includes two main parts: The first part is to process the raw observation data of tracking stations on the earth to get the baseline single day solution and single day orbit determination. The second one is post-processing part, which use the single day orbit resolutions and baseline solutions to estimate the parameters and integrate orbit. The parameters to be estimated in the post-processing include orbit parameters, geodynamic model parameters, station coordinate and velocity parameters, tropospheric parameters, ambiguity parameters, satellite and receiver clock parameters and so on. Complicated functional correlation and error correlation between these parameters cause complex post-processing.The post-processed part of precise position and precise orbit determination is mainly studied in the dissertation. Using the single day solution orbit and the single day baseline solution to estimate various parameters such as station coordinate parameters, station velocity parameters, earth rotation parameters, orbit parameters and to integrate the satellite orbit is investigated in detail. Such study has not been developed systematically yet in our country before. The main achievements and concerned items of the dissertation are as following:(1) Using SINEX(Solution INdependent EXchange Format) files as the main input files in post-processing of GPS POD and precise positioning is proposed in the dissertation. The SINEX file structure and transformation between SINEX file and the normal equation are discussed. SINEX file is the standard format of solution file, baseline solutions derived from GPS, VLBI, SLR etc. and points coordinates, points covariance, a■ priori coordinates and a priori variance information can be found in SINEX file. Data processing combined multi-stages, multi-types and multi-subnets can be done by adding normal equations recovered from SINEX files.(2) Based on the analysis of traditional GPS network adjustment model with baseline pattern, a new generalized network adjustment model with coordinate pattern is brought forward, station coordinates, earth rotation parameters (ERP) etc. are used directly as observations in the new model. The relationship and the different of the two models are analyzed. The advantages of the generalized network adjustment model with coordinate pattern in parameters estimation of multi-types and multi-stages are summarized. The common ways of dada processing of the ne.w model are generalized. The robustified least squares estimator on equivalent variance-covariance method is used to solve the outliers problem on the generalized network adjustment model with coordinate pattern.(3) The influence of the a priori constraint in parameter estimation are analyzed in detail with consideration of function model error and stochastic model error. The influence of the error of the a priori constraint value and the a priori constraint covariance on estimated parameters is derived. This study also demonstrates that the elimination of the a priori constraint is the inverse process of additional constraint. The algorithm of elimination the a priori constraint is presented.(4) Based on indirect adjustment model with additional constraint condition, the influence of additional extra constraint conditions on adjustment results is deduced. With the condition of decreasing the variance of unit weight (variance factor) <x0, the conditionof that adding extra constraint brings plus is analyzed. The conclusion is that the quality of solution can’t be improved with additional constraints all the time.(5) Using the way of parameters transformation to unify the basic algorithms such as unification of the a priori initial value of parameters, the parameters merging, normal equations adding, unknown parameters introducing, normal equation normalization and so on is proposed. Some key issues in the algorithms realization of generalized network adjustment model with coordinate pattern are deduced in details, which is the theoretic base used to realize generalized net adjustment model with coordinate pattern.(6) The parameters estimation issues of the new model have been mainly investigated. The estimated parameters include stations coordinate, station velocity, earth rotation and so on. In addition, the software has been developed in the research. The examples demonstrate that there is difference between the true fact and estimated velocity if weassume the station velocity keep constant when we estimate the stations velocity. Moreover, the empirical model of the velocity variation of the station has been established by regressive analysis method based on week solution coordinate series of the station. With respect to the velocity of IGS tracking station, it had better to model the variation periodically or to give a velocityperiodically using piece-wise linear function rather than using a linear variable to estimate its bias.(7) The algorithm of using single day solution to integrate multi-day solution by the way of orbit overlaying are conducted in details. An example is given, which proves that the orbit integration method can improve the accuracy of orbit efficiently. Especially in local area orbit determination, orbit integration can greatly improve the accuracy of the orbit. Finally, Multi-days orbits integrated solutions from different analysis centers are investigated in details. Comparison has been made between the solution of IGS analysis center and integrated orbit solution from the above model.更多还原