  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.
