New GPS deformation monitoring algorithm applied to Donghai bridge

A real-time, long-round global positioning system (GPS) bridge-deformation monitoring technology was proposed, which processes the carrier phase of multiple GPS receivers in an operation center. It was demonstrated an extended Kalman filter with triple differential ionospheric-free measurement (EKF-TIF) which can eliminate the ionospheric delay, whiten the TIF noise and optimize the results of EKF, consequently, achieves a better performance than existing real time kinematic (RTK) solution. An experiment, which takes an active ionosphere condition into consideration, proves the feasibility of this system by comparing its records to that of a traditional RTK solution, practically, the system installed on the Donghai Bridge has survived a non-break running for five months. The analysis to the monitoring records shows the system achieves the designed accuracy and reliability.