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.

Cite this article as:

Geng J, Wen Q, Zhang T*, Li C (2020) Strong-motion seismogeodesy by deeply coupling GNSS receivers with inertial measurement units