Suspension Cable Bridge Deflection Determination Using Kinematic PPP with High-Rate GPS Satellite Clock Corrections

Abstract

Many previous studies have utilized the advantages of GPS for structural health monitoring however high data rate (higher than 1 Hz) is required for structures’ vibration detection using GPS. This paper investigates the advantages of utilizing high-rate satellite clock in a kinematic PPP processing strategy specifically applied to the detection of bridge displacement. Global distributed IGS stations high rate observations were used for GPS satellite clock estimations. The Uncalibrated Phase Delay (UPD) and the Zenith Total Delay (ZTD) parameters were firstly estimated using PPP in static mode. The GPS satellite clock product with 1 Hz sampling rate were successfully estimated by applying the UPD and tropospheric delays as compensations to the carrier phase. The deformation of the suspension cables (20 Hz datasets) and towers (10 Hz datasets) were estimated using both the kinematic PPP, using the 1 s, 30 s, 300 s clocks, and the DD data processing method. The 1 s GPS satellite clock gave the most precise and stable solution when compared with the 30 s and 300 s clocks obtained from IGS. Correlation coefficient of PPP solution and DD solution reflects bridge displacement waveform using 1 s PPP is more consistency and accuracy. The 1 s PPP is an alternative method for suspension cable bridge deflection determination, particular in the scenario that DD is impossible due to failure of reference station.