Hervás Marcos, Bergadà Pau, Alsina-Pagès Rosa Ma
GTM-Grup de recerca en Tecnologies Mèdia, La Salle-Universitat Ramon Llull, c/Quatre Camins, 30, 08022 Barcelona, Spain.
Wavecontrol, c/Pallars, 65-71, 08018 Barcelona, Spain.
Sensors (Basel). 2020 Apr 28;20(9):2486. doi: 10.3390/s20092486.
High Frequency (HF) communications through ionospheric reflection is a widely used technique specifically for maritime, aeronautical, and emergency services communication with remote areas due to economic and management reasons, and also as backup system. Although long distance radio links can be established beyond line-of-sight, the availability, the usable frequencies and the capacity of the channel depends on the state of the ionosphere. The main factors that affect the ionosphere are day-night, season, sunspot number, polar aurora and earth magnetic field. These effects impair the transmitted wave, which suffers attenuation, time and frequency dispersion. In order to increase the knowledge of this channel, the ionosphere has been sounded by means of narrowband and wideband waveforms by the research community all over the world in several research initiatives. This work intends to be a review of remarkable projects for vertical sounding with a world wide network and for oblique sounding for high latitude, mid latitude, and trans-equatorial latitude.
通过电离层反射进行的高频（HF）通信是一种广泛应用的技术，由于经济和管理原因，以及作为备用系统，它特别适用于与偏远地区的海事、航空和应急服务通信。尽管可以建立超视距的长距离无线电链路，但信道的可用性、可用频率和容量取决于电离层的状态。影响电离层的主要因素有昼夜、季节、太阳黑子数、极地极光和地磁场。这些效应会削弱发射波，使其遭受衰减、时间和频率色散。为了增进对该信道的了解，世界各地的研究团体在多项研究计划中通过窄带和宽带波形对电离层进行了探测。这项工作旨在回顾利用全球网络进行垂直探测以及针对高纬度、中纬度和跨赤道纬度进行斜向探测的重要项目。
