Deflections and frequency responses of the Forth Road Bridge measure by GPS

Using kinematic GPS to monitor the deflections of large suspension bridges is an area of joint research at the University of Nottingham and Brunei University, The technique to enable the magnitude of both the deflections and frequencies to be measured is well established. Many novel techniques have been developed which tackle the issues of multipath on such structures as well as tropospheric issues and integration of the GPS with pseudolites and accelerometers to enhance the satellite signals.

The following paper reports some elements of experiments carried out using the Forth Road Bridge in Scotland in February 2005. 46 hours of data were collected on a continuous basis. Two GPS reference stations were located on the south side of the north-south orientated bridge. A further 5 GPS receivers were placed upon the bridge's deck, situated in an optimum layout, and two GPS receivers were placed on top of the southern support towers. The receivers were Leica survey grade SR530 and 510 receivers, and data was gathered at a rate of 10Hz.