Pinciples of Using Integrating GPS and Triazial Accelerometers in Surveying Displacement of Large Span Bridges

Detailed information about the characterisitic deflections of large structures such as bridges and tall buildings can help to determine the “health” 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 everincreasing 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 defections 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 ben proven useful for such monitoring , allowing precise readings at rates of up to, 1.000 Hz. However , both systems have their limitations , this paper presents the principle deformation monitoring for bridge, GPS satellite geometry and its impacts on bridge deflection monitoring , the principle of deck (of bridge) geometry adjustment and 3.Coordinate Transformation and Attitude Determination for the Bridge Deck.