基于kalman滤波的近实时电离层TEC监测与反演

发布时间：2018-05-15 21:15

本文选题：电离层 + GPS　；参考：《长安大学》2013年博士论文

【摘要】：电离层是近地空间环境的重要组成部分，电离层的研究可以促进人们认识日地空间系统的整体行为，进而更好地为人类的空间活动服务，因此电离层的研究具有重要的意义。近年来，随着人类空间活动和卫星通讯系统的增多，对电离层各种变化特征及规律（尤其是时空变化）的监测和反演的需求也越来越强烈。目前，利用GPS解算电离层总电子含量（Total Electron Content,TEC）已经成为监测电离层活动的主要技术，而国内外大大小小不同尺度、密度的连续运行GPS观测站网为电离层的局域、区域、全球特性研究提供了平台。国际GNSS服务中心（InternationalGNSS Service,IGS）从1998年开始提供每天的全球电离层TEC分布图（Global IonosphereMap，缩写为GIM），，但是IGS各数据处理中心发布的电离层IONEX文件在时间和空间上的分辨率都不高，由于在中国范围内IGS的观测站数目不多，因此它的精度也不理想，并且IONEX文件并不是GPS特定的格式,它是非GPS用户使用IGS电离层产品的一种接口。因此通过建立一个区域的GPS观测站网，利用实时的GPS电离层观测数据建立电离层模型，监测、现报/预报电离层活动，可以为区域内单频GPS用户提供电离层延迟改正信息。本文正是基于这一背景，在西安地区选取4个GPS双频观测站网，采用kalman滤波对电离层的时空变化实时监测，并且选择地质统计学中常用的kriging方法重构了西安区域电离层TEC地图。本文的主要研究工作和成果如下： 1.系统研究了GIPSY (GNSS-Inferred Positioning System)中周跳探测与修复的Turboedit算法，在此基础上对TurboEdit方法的周跳探测条件进行分析，对于该方法中每一历元之前的所有宽巷模糊度整体求平均的方法，采用滑动平均的方法替代，同时在电离层残差组合中，采用了相邻历元的载波相位电离层残差组合求差的方法，从而避免引入观测噪声较大的伪距电离层残差组合。实验表明：改进后的TurboEdit法对于发生在观测数据质量不好的周跳、Turboedit法的探测盲点以及频繁周跳的探测能力都有所提高。 2.进行倾斜路径电离层实时提取时，利用伪距提取的TEC P修正载波相位提取TEC的方法，实例结果表明：修正后的电离层TEC与伪距提取的倾斜路径电离层TECP吻合较好，能够反映出的伪距观测提取电离层TEC P的趋势走向，但是修正后的电离层TEC数据更加平滑、集中；采用切比雪夫（Chebyshev）多项式对GPS卫星轨道进行拟合内插；计算了电离层穿刺点的位置坐标。 3.采用Kalman滤波估计出每个观测历元的电离层模型系数以及测站和卫星的硬件延迟，达到了实时监测电离层活动的目的。将GPS观测数据直接解算的电离层TEC与kalman滤波算法处理后的垂直TEC进行比较，结果表明：kalman滤波解算的电离层垂直TEC能够实时反映电离层TEC的活动变化。 4.采用Kriging方法对西安区域电离层TEC地图进行了重构，并通过CODE分析中心提供的最终TEC产品对本文解算结果进行了验证，结果表明本文解算结果与CODE的结果基本相当。
[Abstract]:The ionosphere is an important part of the near earth space environment. The study of ionosphere can promote people to understand the overall behavior of the solar terrestrial space system and serve the human space activities better. Therefore, the study of the ionosphere is of great significance. In recent years, with the increase of human space activities and satellite communication systems, the ionosphere has been applied to the ionosphere. The demand for monitoring and inversion of various change characteristics and laws, especially spatio-temporal changes, is also increasing.
At present, using GPS to calculate Total Electron Content (TEC) has become the main technology to monitor the activity of the ionosphere, and the continuous operation of GPS observation station network of density is a platform for the study of the local, regional and global characteristics of the ionosphere. The international GNSS Service Center (InternationalGNSS). Service, IGS) has provided a daily global ionospheric TEC distribution map (Global IonosphereMap, abbreviated as GIM) from 1998, but the resolution of the ionospheric IONEX files issued by the IGS data processing centers is not high in time and space. Because the number of IGS observation stations in China is low, its accuracy is not ideal, and I is not ideal. And I ONEX file is not a specific GPS format, it is an interface for non GPS users to use IGS ionospheric products. So by establishing a GPS observation station network in a region, using real-time GPS ionospheric observation data to establish the ionospheric model, monitoring, present / forecast ionospheric activities, which can be considered as a single frequency GPS user in the region to provide the ionospheric delay. Based on this background, this paper selects 4 GPS dual frequency Observatory networks in Xi'an area, uses Kalman filtering to monitor the spatio-temporal changes of the ionosphere in real time, and reconstructs the TEC map of the ionosphere in the Xi'an region by selecting the Kriging method commonly used in geostatistics.
The main research work and achievements of this paper are as follows:
1. systematically studies the Turboedit algorithm for detecting and repairing the cycle jump in GIPSY (GNSS-Inferred Positioning System). On this basis, the detection conditions of the cycle jump of the TurboEdit method are analyzed. The method of averaging all the wide alley ambiguities before each epoch in this method is replaced by a sliding mean method and at the same time in the electricity. In the residual residual combination, the difference combination method of the carrier phase ionosphere residual combination of adjacent epochs is adopted to avoid the introduction of the pseudo range ionosphere residual combination with large observation noise. The experiment shows that the improved TurboEdit method is for the week jump, the blind spot of the Turboedit method and the frequent cycle jump in the poor observation data quality. The detection ability has been improved.
2. in the real-time extraction of the inclined path ionosphere, the method of extracting TEC from the carrier phase of the pseudo distance extracted TEC P is used. The example shows that the corrected ionosphere TEC is in good agreement with the pseudo distance extraction of the inclined path ionosphere TECP, and can be reflected by the pseudo distance observation to extract the trend trend of the ionospheric TEC P, but the corrected ionization is used. The layer TEC data are more smooth and concentrated, and the GPS satellite orbit is interpolated with Chebyshev (Chebyshev) polynomials, and the position coordinates of the ionospheric puncture point are calculated.
3. the Kalman filter is used to estimate the ionosphere model coefficient of each observation epoch and the hardware delay of the station and satellite. The purpose of real-time monitoring of the ionospheric activity is achieved. The ionospheric TEC calculated directly by the GPS observation data is compared with the vertical TEC processed by the Kalman filtering algorithm. The results show that the ionosphere is calculated by Kalman filtering. Vertical TEC can reflect the changes of ionospheric TEC in real time.
4. the Kriging method is used to reconstruct the Xi'an regional ionosphere TEC map, and the final TEC product provided by the CODE analysis center is verified by the results of this paper. The results show that the results of this paper are basically equivalent to the results of CODE.

【学位授予单位】：长安大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：P352;P228.4

【引证文献】