12:00 PM - 12:15 PM
[PEM12-30] Enhanced HF-START Web System for Visualizing HF Radio Wave Propagation in the Variable Atmosphere-Ionosphere Coupled System
Keywords:HF-START, short wave propagation, ionosphere, space weather
HF-START (High Frequency Simulator Targeting for All-users' Regional Telecommunications) is a high-frequency (HF) radio wave propagation simulator designed for HF communication and space weather applications. The system is accessible via a web interface at https://hfstart.nict.go.jp. The simulator visualizes HF radio wave propagation paths between arbitrary two points within Japan estimated by raytracing method using electron density information derived from real-time GNSS observations. Additionally, it provides global propagation with predictions up to approximately one day in advance using electron density data from a global atmosphere-ionosphere coupled model, GAIA (Ground-to-Topside Model of Atmosphere and Ionosphere for Aeronomy). The website also displays real-time propagation conditions. The service commenced in March 2021, and recent access statistics indicate approximately 20-80 visits per day, with peak usage reaching approximately 400 visits.
The HF-START website is scheduled to release an updated version in March 2025, incorporating the following three major improvements. First, the estimation of total attenuation is added. HF radio waves are attenuated during ionosphere passage and ground reflections, and the ability of radio waves to reach their destination depends on the amount of attenuation. The system considers (i) ionospheric attenuation, estimated using collision frequency derived from GAIA along with the aforementioned electron density information, and (ii) attenuation by ground reflections. Second, a long-path calculation function is added. Long-path propagation —which is a path ~180 degrees opposite to the great circle course (short-path) that connects two points on Earth via the shortest distance— can sometimes provide more effective communication than short-path propagation, depending on ionospheric conditions. Third, real-time propagation conditions for amateur radio frequency bands have been added in response to user requirements.
In this presentation, we will introduce the framework for these improvements and demonstrate characteristic propagation patterns corresponding to ionospheric variations.
The HF-START website is scheduled to release an updated version in March 2025, incorporating the following three major improvements. First, the estimation of total attenuation is added. HF radio waves are attenuated during ionosphere passage and ground reflections, and the ability of radio waves to reach their destination depends on the amount of attenuation. The system considers (i) ionospheric attenuation, estimated using collision frequency derived from GAIA along with the aforementioned electron density information, and (ii) attenuation by ground reflections. Second, a long-path calculation function is added. Long-path propagation —which is a path ~180 degrees opposite to the great circle course (short-path) that connects two points on Earth via the shortest distance— can sometimes provide more effective communication than short-path propagation, depending on ionospheric conditions. Third, real-time propagation conditions for amateur radio frequency bands have been added in response to user requirements.
In this presentation, we will introduce the framework for these improvements and demonstrate characteristic propagation patterns corresponding to ionospheric variations.