Integration of GPS and tiltmeters for structure monitoring

GPS has been studied extensively in recent years for monitoring structural dynamics and deformation. The technology offers a number of advantages in such applications. It is however well known that GPS observations are often affected by error sources such as the GPS signal multipath effects especially on observation sites where there are smooth reflective surfaces such as structure surfaces on a building roof or the suspension cables on a cable stayed bridge. The errors often render the GPS observations inaccurate and unreliable. We investigate in this research into a structure monitoring system where GPS and a tiltmeter are integrated on a common platform so that the GPS and the tiltmeter measurements can be integrated. Since the error sources of GPS and the tiltmeters are different, the combined system makes good use of the complementary natures of the sensors to derive better monitoring results. The integrated system, the data processing and analysis involved and some experimental results are presented.