Terrestrial mobile gravimetry using a temperature stabilized IMU

Abstract Terrestrial mobile gravimetry using temperature-stabilized inertial measurement units (IMUs) is emerging as an efficient technique for acquiring high-accuracy gravity data in dynamic environments. This study explores the integration of the iCORUS-2 IMU system with GNSS along the Cebeci-Elmadağ route in Ankara, Türkiye. The iTempStab technology was incorporated into the iCORUS-2 system to stabilize temperature variations to enhance the accuracy of gravity measurements. Notably, this research represents the results of vehicle-based terrestrial mobile gravimetry using a thermally stabilized IMU. An extended Kalman filter (EKF) was applied to integrate IMU and GNSS data. The advantage of terrestrial mobile gravimetry over airborne methods is the ability to make static updates for vertical gravity, zero gravity gradient and zero velocity measurements, which can be introduced into the EKF as measurement updates. The method was tested by analysing the statistical impact of these updates at varying intervals: without any gravity measurement updates, and by applying updates at approximately 2 km, 3 km, 4 km, 5 km, 6 km, and 7 km intervals. Results indicated that without updates, a root mean square error (rmse) value between external terrestrial gravity data and mobile gravimetry estimates is 1.362 mGal. However, with updates at approximately 2 km intervals, the rmse value significantly decreased to 0.948 mGal, representing a %30.4 reduction in rmse and achieving sub-mGal accuracy. The inclusion of temperature stabilization and frequent gravity measurement updates demonstrated a marked improvement in data accuracy and consistency. These advancements not only validate the potential of mobile gravimetry for geophysical surveys but also broaden its applications in fields requiring precise gravity data acquisition.