Automatic Detection of Omega Signals Captured by the Poynting Flux Analyzer (PFX) on Board the Akebono Satellite

TL;DR

This paper presents an automatic detection method for Omega signals captured by the PFX instrument on the Akebono satellite, enabling large-scale analysis of VLF wave propagation in Earth's magnetosphere.

Contribution

The study introduces a systematic, reliable detection algorithm for Omega signals in satellite data, facilitating extensive statistical analysis of signal propagation.

Findings

Detected over 43,000 magnetic field signals and 111,000 electric field signals.

Confirmed propagation of Omega signals along Earth's magnetic field lines.

Demonstrated the method's effectiveness for long-term statistical studies.

Abstract

The Akebono satellite was launched in 1989 to observe the Earth's magnetosphere and plasmasphere. Omega was a navigation system with 8 ground stations transmitter and had transmission pattern that repeats every 10 s. From 1989 to 1997, the PFX on board the Akebono satellite received signals at 10.2 kHz from these stations. Huge amounts of PFX data became valuable for studying the propagation characteristics of VLF waves in the ionosphere and plasmasphere. In this study, we introduce a method for automatic detection of Omega signals from the PFX data in a systematic way, it involves identifying a transmission station, calculating the delay time, and estimating the signal intensity. We show the reliability of the automatic detection system where we able to detect the omega signal and confirmed its propagation to the opposite hemisphere along the Earth's magnetic field lines. For more than three years (39 months), we detected 43,734 and 111,049 signals in the magnetic and electric field, respectively, and demonstrated that the proposed method is powerful enough for the statistical analyses.