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Strong‐Motion Seismogeodesy by Deeply Coupling GNSS Receivers with Inertial Measurement Units
Author(s) -
Geng Jianghui,
Wen Qiang,
Zhang Tisheng,
Li Chenghong
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl087161
Subject(s) - gnss applications , inertial measurement unit , geodesy , amplitude , geology , global positioning system , computer science , displacement (psychology) , acoustics , remote sensing , physics , telecommunications , optics , computer vision , psychology , psychotherapist
Global navigation satellite system (GNSS) displacements at near‐source stations can be biased in both amplitude and phase due to fierce earthquake strike. We propose to inject inertial measurement unit (IMU)‐recorded ground motions into GNSS receivers to compensate their phase‐lock loops (PLLs) for seismic motion stress, aiming at keeping steady carrier‐phase tracking. We use a shake table to replay an acceleration record (0.5–2.0 g) from the 2008 Mw7.9 Wenchuan earthquake to test this IMU‐augmented PLL: It achieves a 1.9‐mm amplitude error (RMS) and an 8.0‐ms phase lag against the shake table's recordings, while the conventional PLL languishes to 6.0 mm and 56.5 ms, respectively. Moreover, the IMU‐augmented PLL enables a six‐degree‐of‐freedom integration among the GNSS and IMU data, where the displacement amplitude error and phase lag decline further to 0.9 mm and 3.5 ms, respectively. We believe that the IMU‐augmented GNSS receivers are ideal strong‐motion seismograph to capture trustworthy broadband displacements in the near fields.