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

摘要

The Akebono satellite was launched in 1989 to observe the Earth'smagnetosphere and plasmasphere. Omega was a navigation system with 8 groundstations transmitter and had transmission pattern that repeats every 10 s. From1989 to 1997, the PFX on board the Akebono satellite received signals at 10.2kHz from these stations. Huge amounts of PFX data became valuable for studyingthe propagation characteristics of VLF waves in the ionosphere andplasmasphere. In this study, we introduce a method for automatic detection ofOmega signals from the PFX data in a systematic way, it involves identifying atransmission station, calculating the delay time, and estimating the signalintensity. We show the reliability of the automatic detection system where weable to detect the omega signal and confirmed its propagation to the oppositehemisphere 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 andelectric field, respectively, and demonstrated that the proposed method ispowerful enough for the statistical analyses.