Propagation characteristics of power line harmonic radiation in the ionosphere

Theoretical model and solutions on power line harmonic radiation （PLHR） propagating in the ground, air, and anisotropic homogeneous ionosphere are presented, The theoretical model is verified by the PLHR events observed by the DEMETER satellite. Some propagation characteristics of PLHR based on the model are obtained. This paper is bene- ficial to quantitatively interpret the formation mechanism of PLHR phenomenon.     

Global characteristics of the second-order ionospheric delay error using inversion of electron density profiles from COSMIC occultation data

It is a well known fact that ionospheric delay error is a predominant factor which influences the positioning accuarcy of GNSS.Although the main part of the first-order ionospheric delay error can be removed by the frequency-dependent behaviors of the ionosphere,the second-order ionospheric delay error must be eliminated to achieve millimetre-scale positioning accuracy.Due to COSMIC occultation providing electron density profiles on the global scale,the paper presents the first-order and the second-order ionospheric delay error analysis on the global scale using the inversion of electron density profiles from COSMIC occultation data during 2009–2011.Firstly,because of the special geographical location of three ISR(incoherent scatter radar),the first-order and the second-order ionospheric delay errors are calculated and discussed;the paper also shows and analyzes the diurnal,seasonal,semi-annual variation of ionospheric delay error with respect to signal direction.Results show that for the L1 signal path,the first-order ionospheric delay error is the largest near the equator,which is circa 7 m;the maximum second-order ionospheric delay error are circa 0.6 cm,0.8 cm and 0.6 cm respectively for L1 signals coming from the zenith,the north and the south at 10 degree elevation angles.The second-order ionospheric delay error on the L1 signal path from zenith are the symmetry between 15°and 15°with respect to magnetic equator,and are nearly zero at the magnetic equator.For the first time,the second-order ionospheric delay error on the global scale is presented,so this research will greatly contribute to analysing the higher-order ionospheric delay error characteristics on the global scale.     

天波雷达电离层信道可用度统计方法研究

分析了影响天波超视距雷达(OTHR)可用度的电离层信道因素,依据一个太阳活动周期(11年)的电离层不稳定性数据,统计了中纬、中低纬和低纬地区的电离层信道可用度,OTHR频率管理系统综合考虑了电离层的基本特性以及高频干扰频谱分布特性,首次提出了基于频率管理系统工作频率表数据的电离层信道可用度的短期统计方法,并对太阳活动低年特定月份典型时刻(日出、日落、正午和夜间)的电离层信道可用度进行了统计分析.     

中国大陆14次强震前电离层异常统计分析

地震电离层扰动规律统计分析对开展地震监测、预测意义重大。利用四分位数法对中国大陆地区14次Ms≥7.0地震前电离层foF2进行了统计,进一步证实了地震电离层异常的存在,并分析了地震电离层异常扰动的时间、空间分布规律以及扰动形态特点,给出电离层foF2扰动与地震各要素之间的关系。统计结果表明:85.7%(12次)的地震在震前出现电离层异常,并且大部分分布在震前7天以内的11∶00LT～17∶00LT;此外,电离层foF2扰动幅度与即将发生的地震震级、震源深度、震中距离存在不同程度的相关性。