A drilling combination positioning method based on geomagnetic/inertial navigation combined with PSD improved unscented Kalman filtering algorithm*

Abstract During the drilling process, the accuracy of measuring drilling tool attitude is severely affected by measurement drift errors in the inertial device itself and the significant interference noise generated by the impact vibration of the drill bit. To address these issues and achieve precise measurement of drilling trajectory, this paper proposes a combined positioning method based on geomagnetism/inertial navigation combined with PSD improved unscented Kalman filtering. An experimental platform was constructed, and a sensor system was installed in the vicinity of the drill bit for short section measurements. Experimental verification was conducted using actual drilling data. The results demonstrate that, compared to general unscented Kalman filtering, the average position error using PSD improved unscented Kalman filtering was reduced from 0.122 m to 0.088 m, and the average velocity error was reduced from 0.019 m s −1 to 0.005 m s −1 . By comparing and matching with the drilling trajectory drawn in the logging process, the overall positioning accuracy of the combined positioning method is as high as 90.8%, yielding positioning results that are highly authentic and effective, thereby meeting the on-site usage requirements.