Research on RTK tilt position measurement method based on UKF

Aiming at coordinates of some points cannot be measured directly due to the limits of terrain and instruments in actual measurement, a novel real-time kinematic (RTK) tilt position measurement method is proposed in this study. Traditional GPS static measurement method cannot gain positioning results real time. In contrast, RTK can provide real-time 3D positioning results of stations in specified coordinate system and the positioning error is centimetre scale. Taking coordinates of points on spherical model as observation, the coordinates of measurement points are got indirectly through estimating positions of sphere centre based on unscented Kalman filter (UKF). Three schemes are designed to verify the performance of the proposed method through convergence and estimated errors. As the semi-physical simulation shows, the proposed method has better performance and is simple and easy to operate. Besides, the proposed method can smooth noise of measurement points and it can realise centimetre-level position accuracy without any auxiliary equipment, which effectively avoids measurement error caused by centering rod tilt.