THE COMPARISON OF SINGLE FREQUENCY AND DUAL FREQUENCY GPS FOR BRIDGE DEFLECTION AND VIBRATION MONITORING

The use of dual frequency code/carrier phase GPS data has been shown to be a feasible tool for bridge deflection monitoring. This is due to the quick On The Fly integer ambiguity resolution that is possible through using the dual frequency data in order to create the wide lane observable. The applications of OTF dual frequency data are numerous, whereby OTF ambiguities are resolved in seconds. Single frequency code/carrier phase GPS receivers are less expensive than dual frequency receivers however the time taken to resolve integer ambiguities in an OTF manner is in the order of 15 minutes. This is due to the wide lane observable not being available. The following paper details the precision obtainable using single frequency receivers compared to dual frequency, in the context of measuring the deflections of a bridge. Instead of using OTF, a stop and go technique is used to resolve integer ambiguities within a few minutes