Wenyao Zhu

Co-seismic ionospheric and deformation signals on the 2008 magnitude 8.0 Wenchuan Earthquake from GPS observations

The 8.0 magnitude Wenchuan Earthquake occurred at the Longmenshan Fault along the eastern boundary between the Tibetan Plateau and the western Sichuan Basin in southwestern China on 12 May 2008, killing tens of thousands of people in several cities along the western Sichuan Basin. In this paper, co-seismic ionospheric and deformation signals from the mainshock of this event are extracted from national global positioning system (GPS) network observations, which provide unique insights into this event. The co-seismic deformation moves towards the earthquake epicentre, and the largest magnitude reaches 2.3 m in Beichuan. The total moment of the co-seismic rupture is 2.4 × 1021 nm, equivalent to a magnitude of 8.1 and nearly identical to the seismological estimate. Furthermore, co-seismic ionospheric disturbances indicate a shock-acoustic wave propagation at a mean velocity of about 600 m s−1 towards the rupture direction.

Estimation of differential code biases for Beidou navigation system using multi-GNSS observations: How stable are the differential satellite and receiver code biases?

Differential code biases (DCBs) are important parameters that must be estimated accurately and reliably for high-precision GNSS applications. For optimal operational service performance of the Beidou navigation system (BDS), continuous monitoring and constant quality assessment of the BDS satellite DCBs are crucial. In this study, a global ionospheric model was constructed based on a dual system BDS/GPS combination. Daily BDS DCBs were estimated together with the total electron content from 23 months’ multi-GNSS observations. The stability of the resulting BDS DCB estimates was analyzed in detail. It was found that over a long period, the standard deviations (STDs) for all satellite B1–B2 DCBs were within 0.3 ns (average: 0.19 ns) and for all satellite B1–B3 DCBs, the STDs were within 0.36 ns (average: 0.22 ns). For BDS receivers, the STDs were greater than for the satellites, with most values

Analysis of the ionosphere wave-motion with GPS

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Micro-plate tectonics and kinematics in Northeast Asia inferred from a dense set of GPS observations

<2 ns. The DCBs of different receiver families are different. Comparison of the statistics of the short-term stability of satellite DCBs over different time intervals revealed that the difference in STD between 28- and 7-day intervals was small, with a maximum not exceeding 0.06 ns. In almost all cases, the difference in BDS satellite DCBs between two consecutive days was

Present‐Time Crustal Deformation in China and its Surrounding Regions by GPS

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Monitoring of Small-Scale Ionospheric Irregularity Using Local GPS Network

<0.8 ns. The main conclusion is that because of the stability of the BDS DCBs, they only require occasional estimation or calibration. Furthermore, the 30-day averaged satellite DCBs can be used reliably for the most demanding BDS applications.