Slow structural deformation monitoring using Locata - a trial at Tumut Pond Dam.

Locata Corporation's positioning technology 'Locata' is a terrestrial-based RF-ranging technology that provides high accuracy position solutions using a network (LocataNet) of time synchronised pseudolite-like transceivers (LocataLites). This technology provides centimetre level accurate position solutions for static positioning using carrier phase measurement data which provides an advantage over other technology for monitoring structural movement in many applications. The Locata network can be deployed in such a configuration around a structure that optimal network geometry could be ensured despite site constraints. This paper describes the first deformation trial using Locata technology carried out at Tumut Pond Dam, in the state of New South Wales, Australia. This trial was run for 22 hours and yielded millimetre-level precision for horizontal positions, and centimetre-level vertical precision for all observed epochs. The accuracy of the coordinate solutions was at the few millimetre level with standard deviations of 2.5 mm, 2.1 mm and 18 mm for the east, north and height components respectively. The position solutions were generated by an iterative least squares estimation process of Locata carrier phase observations per epoch. Then mean of sixty seconds coordinate solutions was used as input for a Kalman filter. Standard deformation detection methods were applied. No significant displacement was observed during this trial. [ABSTRACT FROM AUTHOR]