GNSS广播电离层精度监测评估方法研究

发布时间：2018-03-09 14:45

本文选题：GNSS　切入点：广播电离层模型　出处：《长安大学》2015年硕士论文　论文类型：学位论文

【摘要】：广播电离层模型是削弱电离层延迟误差的重要手段,是单频接收机提高导航、定位精度的有效途径。GNSS(包括GPS/BDS/Galileo)通过向用户发播电离层参数实现电离层延迟修正,同时GNSS系统通过不断完善监测网与处理策略优化和发展其全球广播电离层模型。随着GNSS应用日益广泛,各系统之间的兼容与互操作也相继开展。因此,在统一标准下开展卫星导航系统性能评估十分必要,其中,广播电离层精度监测评估是一项主要内容。为及时、准确地评估广播电离层精度需选择精度更高、可靠性更强的电离层评估基准以及适当的评估方法。目前,主要采用IGS(CODE)电离层格网(GIM)作为GNSS广播电离层精度评估的基准,然而考虑到CODE模型在我国区域内布站的不足,本文开展了基于改进CODE模型电离层格网评估,以及基于基准站实测电离层评估等方法的研究,并对GNSS广播电离层精度监测评估展开试验。主要研究内容与成果概括如下:(1)详细阐述了GNSS电离层建模及评估的基本理论,分析了电离层延迟误差的影响,给出了GNSS电离层延迟改正的模型与方法。(2)开展了以CODE GIM为基准的广播电离层精度的监测评估,分析了GPS/BDS/Galileo广播电离层模型改正精度。(3)顾及CODE模型在我国境内布站的不足,提出改进CODE模型(亦称CODE+模型)电离层格网评估法,通过增加国内监测站数据,提高了我国及周边地区的电离层建模精度,在此基础上开展了GPS/BDS/Galileo广播电离层精度监测评估试验。(4)基于实测数据建立的全球电离层基准,以基准站实测站星视线上电离层延迟为参考,实现了基于基准站实测电离层的GNSS广播电离层精度评估。(5)比较了基于CODE GIM、改进CODE模型GIM,以及基准站实测电离层评估三种GNSS广播电离层精度监测评估的优缺点。通过试验分析,结果表明三种方法评估结论一致,中国及周边区域BDS广播电离层模型精度高于GPS与Galileo,改正率平均75%左右,GPS模型精度最差;Klobuchar模型中、高纬度精度高于低纬度,表现出电离层明显的纬度相关特性。
[Abstract]:Broadcast ionospheric model is an important means to weaken the ionospheric delay error, and it is an effective way for single-frequency receiver to improve navigation and positioning accuracy. GNSS (including GPS / BDS / Galileo) realizes ionospheric delay correction by broadcasting ionospheric parameters to users. At the same time, the GNSS system optimizes and develops its global broadcast ionospheric model by continuously improving the monitoring network and processing strategy. With the increasing application of GNSS, the compatibility and interoperability among the various systems are carried out one after another. It is necessary to carry out the performance evaluation of satellite navigation system under the unified standard, in which the monitoring and evaluation of broadcast ionospheric accuracy is a main content. In order to evaluate the broadcast ionospheric accuracy in a timely and accurate manner, it is necessary to select a higher accuracy. Ionospheric evaluation datum with higher reliability and appropriate evaluation methods. At present, the ionization grid (GIMM) is mainly used as the benchmark for the accuracy evaluation of the GNSS broadcast ionosphere. However, considering the shortage of the CODE model in the regional distribution of stations in our country, In this paper, the methods of ionospheric grid evaluation based on the improved CODE model and the ionospheric evaluation based on the reference station are studied. The main research contents and results are summarized as follows: (1) the basic theory of GNSS ionospheric modeling and evaluation is described in detail, and the influence of ionospheric delay error is analyzed. The model and method of GNSS ionospheric delay correction are given. The monitoring and evaluation of broadcast ionospheric accuracy based on CODE GIM are carried out. The correction accuracy of GPS/BDS/Galileo broadcast ionospheric model is analyzed. An improved CODE model (also called CODE model) is proposed to evaluate the ionospheric grid. The accuracy of ionospheric modeling in China and its surrounding areas is improved by increasing the data of monitoring stations in China. On this basis, the GPS/BDS/Galileo broadcast ionospheric accuracy monitoring and evaluation test. 4) the global ionospheric datum is established based on the measured data, and the ionospheric delay at the satellite line of sight of the reference station is taken as the reference. The accuracy evaluation of GNSS broadcast ionosphere based on the measured ionosphere at the reference station is realized. The advantages and disadvantages of the three kinds of GNSS broadcast ionospheric accuracy monitoring and evaluation are compared based on the CODE Gims, the improved CODE model and the base station ionospheric evaluation. The results show that the accuracy of BDS broadcast ionospheric model in China and its surrounding regions is higher than that of GPS and Galileo, and the average correction rate is about 75%. In Klobuchar model, the accuracy of high latitude is higher than that of low latitude. The ionospheric latitudinal correlation is evident.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P228.4

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