VLF signal dataset radiated by NWC transmitter

VLF signal sources include lightning and some submarine communication systems. There are many artificial very low frequency communication stations worldwide, with operating frequencies ranging from 1kHz to 50kHz. The VLF electromagnetic waves emitted by ground based very low frequency artificial sources can be reflected back and forth between the ground and the ionosphere, and propagated to a distance using the Earth ionosphere Waveguide (EIWG). During the propagation process, some energy can also penetrate upwards into the ionosphere and propagate in the form of right-handed polarized whistler waves towards the top of the ionosphere and the magnetosphere, ultimately being received by satellites. Numerous studies have shown that the main energy attenuation of VLF electromagnetic waves propagating upwards occurs in the low ionosphere region, and after passing through the low ionosphere, their energy almost no longer decays. Therefore, the VLF signals received by satellites can effectively reflect low ionospheric information. The dataset used in this study is sourced from the electric field instrument data of the domestically launched Zhangheng-1 satellite, which can be downloaded and obtained from public websites. By processing the raw data, the dataset used in this study was obtained.

甚低频（VLF）信号源包括闪电和部分潜艇通信系统。全球范围内存在众多人工甚低频通信站，其工作频率范围为1kHz至50kHz。地面人工甚低频源发射的甚低频电磁波可在地面与电离层之间来回反射，并借助地球电离层波导（Earth Ionosphere Waveguide, EIWG）向远距离传播。在传播过程中，部分能量还可向上穿透进入电离层，并以右旋极化哨声波的形式向电离层顶部及磁层传播，最终被卫星接收。大量研究表明，向上传播的甚低频电磁波的主要能量衰减发生在低电离层区域，且穿过低电离层后，其能量几乎不再衰减。因此，卫星接收到的甚低频信号可有效反映低电离层信息。本研究使用的数据集来源于国内发射的“张衡一号”卫星的电场仪器数据，该数据可从公共网站下载获取。通过对原始数据进行处理，得到了本研究使用的数据集。