Principles of using integrating GPS and triaxial accelerometers in surveying displacement of large span bridges
Hooshmandzadeh, Mohammed
Detailed information about the characteristic deflections of large structures such as bridges and tall buildings can help to determine the healthh of such a structure as well as to evaluate whether such deflections are the same as those that the structure was designed to tolerate. Due to the ever increasing size of some of these structures, a reliable and accurate health monitoring system could detect uncharacteristic vibrations and deflections, and help prevent disastrous consequences. The use of kinematic GPS has been shown on many occasions to be a viable tool for monitoring the deflections of large structures through its ability to provide cm level precision, at a rate of up to 10 Hz with real time capabilities and with the rover receiver being able to be positioned at a distance of up to ~20 km away from the reference (ideal for long bridges). In addition, accelerometers have been proven useful for such monitoring, allowing precise readings at rates of up to 1,000 Hz. However, both systems have their limitations. GPS is limited partly by multipath and cycle slips as well as the need to have good satellite coverage, whilst accelerometers are limited due to the fact that their readings will drift with time. The integration of the two systems ,however, results in a hybrid arrangement that eliminates the disadvantages of the two separate units. his paper presents an integrated monitoring system, consisting of Leica CRS 1000 series an SR530 dual frequency code/carrier GPS receivers and a Kistler triaxial accelerometer. Two units are physically integrated and their data synchronised. Using spectrum analysis, main natural frequencies are established from the hybrid system. A simple data processing algorithm is presented, as well as the results from field trials to show the potential of such a system .this paper presents the principle of GPS and triaxial accelerometers in large span bridge surveying, advances in realtime GPS deformation monitoring for bridge,GPS satellite geometry and its impacts on bridge deflection monitoring,the principle of deck (of bridge )gemetry adjustment and 3. Coordinate Transformation and Attitude Determination for the Bridge Deck.
Event: XXIII International FIG Congress : Shaping the change
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