基于时域特征分布的核爆电磁脉冲识别算法

In order to discriminate nuclear electromagnetic pulse (NEMP) and lightning electromagnetic pulse (LEMP), an automatic time-domain algorithm at a range of 500 km was proposed. First, for time series of multiple stations emitted by identical source, a method combined of threshold triggering and correlation operation was developed to choose start time of each series. In addition, end time was located according to the height of reflecting layer in the ionosphere, which was estimated through the time difference of direct wave and reflected wave at about 1 000 km distance. Then four parameters were defined to character waveforms. By fitting statistics result with proper probability density function, the four parameters' distribution of LEMP was drawn. Contrasting the distribution with parameters calculated from NEMP data, finally, a discrimination algorithm was obtained. A test was performed to verify the algorithm, which can identify NEMP data and more than 99% of LEMP data at a range of 500 km.