Integration of a Geodetic Grade GNSS Receiver and an Android Dual-Frequency Smartphone with Low-Cost IMU for Seismogeodetic Applications

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Gül C., Öcalan T., Damcı E., Şekerci Ç.

FIG Congress 2022, Warszawa, Poland, 11 - 15 September 2022, vol.1, no.11, pp.1-12

  • Publication Type: Conference Paper / Full Text
  • Volume: 1
  • City: Warszawa
  • Country: Poland
  • Page Numbers: pp.1-12
  • Yıldız Technical University Affiliated: Yes


Global Navigation Satellite Systems (GNSS) can effectively provide semi-static and dynamic displacements by kinematic data processing of high rate observables without any numerical integration process unlike classical seismological sensors such as accelerometers. However, the noise amplitude of the high rate GNSS (HR-GNSS) derived displacements is larger than accelerometers due to various error sources mainly originating from residual atmospheric propagation effects and multipath caused by the receiver set-up environment. Recent advances showed that the integration of geodetic grade HR-GNSS displacements with high-quality accelerometers can provide accurate motion tracking for seismogeodetic applications. However, geodetic grade HR-GNSS and high-quality accelerometers are expensive tools together, and seismogeodesy with these high-grade sensors is not cost-effective. In addition to this, in order to perform HR-GNSS/accelerometer loosely-coupled integration, coordinate frames of these sensors must be aligned. In this study, a low-cost Inertial Measurement Unit (IMU) in the Xiaomi Mi8 smartphone was used in the integration of geodetic grade Trimble NetR9 Precise Point Positioning (PPP) HR-GNSS displacements through a Multi-rate Kalman Filter. The 1999 Düzce Earthquake (Mw = 7.2) in Türkiye and the 1989 Loma-Prieta Earthquake (Mw = 6.9) in the United States of America were simulated on a single axis shake table. In order to provide a cost-effective static alignment for the transformation of the smartphone IMU coordinate frame into the local North East Down frame, Singular Value Decomposition (SVD) was used as combining the smartphone accelerometer and the magnetometer sensors. In addition to this, the same procedure was applied for Xiaomi Mi8 dual-frequency GNSS displacements and accelerometer integration. The Root Mean Square (RMS) values of Trimble NetR9 GNSS/smartphone accelerometer for the Düzce and the Loma-Prieta Earthquake experiments are 4.7 mm and 5.4 mm, respectively. The RMS values of Xiaomi Mi8 dualfrequency GNSS/accelerometer integration are 279 mm for the Düzce Earthquake and 96.7 mm for the Loma-Prieta Earthquake experiments. Results indicate that the integration of geodetic grade HR-GNSS with low-cost IMU is suitable for seismogeodetic applications, whereas Xiaomi Mi8 GNSS/accelerometer integration produces large-scale errors due to the high uncertainty of its dual-frequency GNSS solutions.