A New Method to Improve the Detection of Co-Seismic Ionospheric Disturbances using Sequential Measurement Combination

• Published in: Sensors (Basel, Switzerland) Vol. 19; no. 13; p. 2948
• Main Authors: Kang, Seonho, Song, Junesol, Han, Deokhwa, Kim, Bugyeom, So, Hyoungmin, Kim, Kap-Jin, Kee, Changdon
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 04.07.2019; MDPI
• Subjects: Acoustics; Atmosphere; Bandpass filters; Bias; co-seismic ionospheric disturbances; Delay; Earth; earthquake; Earthquakes; Energy measurement; Engineering Sciences; Global navigation satellite system; Gravitational waves; Gravity; Ionosphere; Ionospheric disturbances; Noise; Signal and Image processing; Signal strength; signal-to-noise ratio; Tsunamis; earthquake; ionosphere; co-seismic ionospheric disturbances; signal-to-noise ratio; Co-seismic Ionospheric Disturbances; Earthquake; Ionosphere; Signal-to-Noise Ratio
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s19132948

Earthquakes generate energy that propagates into the ionosphere and incurs co-seismic ionospheric disturbances (CIDs), which can be observed in ionospheric delay measurements. In most cases, the CID has a weak signal strength, because the energy in the atmosphere transferred from the earthquake dissipates as it travels toward the ionosphere. It is particularly hard to observe at reference stations that are located far from the epicenter. As the number of Global Navigation Satellite System stations and their positions are restricted, it is important to employ weak CID data in the analysis by improving the detection performance of CIDs. In this study, we suggest a new method of detecting CIDs, which mainly uses a sequential measurement combination of the carrier phase-based ionospheric delay data, with a 1-second interval. The proposed method's performance was compared with conventional methods, including band-pass filters and a representative time-derivative method, using data from the 2011 Tohoku earthquake. As a result, the maximum CID-to-noise ratio can be increased by a maximum of 13% when the proposed method is used, and consequently, the detection performance of the CID can be improved.