By calculating the hourly standard deviation of the first-order differences of the horizontal geomagnetic com- ponent minute data, a new index Vr to represent the variation rate of the geomagnetic field was introduced...By calculating the hourly standard deviation of the first-order differences of the horizontal geomagnetic com- ponent minute data, a new index Vr to represent the variation rate of the geomagnetic field was introduced. Vr-indices show similar trends in the temporal change at different observatories and have simultaneous peak values at the observatories cov- ering a large span geographically, which reveals that the source of geomagnetic disturbances represented by Vr is in the mag- netosphere. Based on the comparison among Vr, Kp and ap, it is found that generally Vr changes linearly with Kp and ap, which means that the rapid changes of magnetic field usually exist together with magnetic disturbances. But there are excep- tions. As Vr can be easily produced by individual observatory in quasi real time and is more sensitive to the variation rate of geomagnetic field rather than the field itself, it can be expected to serve for monitoring or predicting the geomagnetic-induced event in a quick and intuitive way.展开更多
针对直方图方法分选脉间参差雷达信号能力不佳且无法解析其调制模式的问题,结合参差信号的交织特性,提出联合到达时间差值(Difference of Time Of Arrival,DTOA)的一阶差分曲线和相关分析的分选方法.该方法基于DTOA一阶差分曲线提取DTO...针对直方图方法分选脉间参差雷达信号能力不佳且无法解析其调制模式的问题,结合参差信号的交织特性,提出联合到达时间差值(Difference of Time Of Arrival,DTOA)的一阶差分曲线和相关分析的分选方法.该方法基于DTOA一阶差分曲线提取DTOA关注项,然后基于关注项的自相关和交叠率识别参差调制模式、基于关注项的互相关分析参差调制模式,最后结合参差分析结果进行序列检索.实验结果表明,所提方法所需计算量较少,可以有效分选参差信号并解析其完整的调制模式,对脉冲丢失表现出较强的适应性,对子周期分布的均匀程度和干扰脉冲有较好的稳健性.展开更多
文摘By calculating the hourly standard deviation of the first-order differences of the horizontal geomagnetic com- ponent minute data, a new index Vr to represent the variation rate of the geomagnetic field was introduced. Vr-indices show similar trends in the temporal change at different observatories and have simultaneous peak values at the observatories cov- ering a large span geographically, which reveals that the source of geomagnetic disturbances represented by Vr is in the mag- netosphere. Based on the comparison among Vr, Kp and ap, it is found that generally Vr changes linearly with Kp and ap, which means that the rapid changes of magnetic field usually exist together with magnetic disturbances. But there are excep- tions. As Vr can be easily produced by individual observatory in quasi real time and is more sensitive to the variation rate of geomagnetic field rather than the field itself, it can be expected to serve for monitoring or predicting the geomagnetic-induced event in a quick and intuitive way.
文摘针对直方图方法分选脉间参差雷达信号能力不佳且无法解析其调制模式的问题,结合参差信号的交织特性,提出联合到达时间差值(Difference of Time Of Arrival,DTOA)的一阶差分曲线和相关分析的分选方法.该方法基于DTOA一阶差分曲线提取DTOA关注项,然后基于关注项的自相关和交叠率识别参差调制模式、基于关注项的互相关分析参差调制模式,最后结合参差分析结果进行序列检索.实验结果表明,所提方法所需计算量较少,可以有效分选参差信号并解析其完整的调制模式,对脉冲丢失表现出较强的适应性,对子周期分布的均匀程度和干扰脉冲有较好的稳健性.
