A novel approach to design measurement models of single-frequency GPS receivers for cost-effective structural monitoring networks

Abstract

The global positioning system (GPS) has become an effective tool for measuring the dynamics of engineering structures from their absolute displacements. Although dual-frequency GPS receivers are widely adopted for structural monitoring applications to guarantee coordinate accuracy of the order of a few centimetres, the associated cost is too high to place larger number of these sensors. It has been recently recognised that single-frequency GPS receivers have great potential to be the smart sensors for measuring structural displacement due to their low-cost, small form-factor and low power consumption. Hence, the structural monitoring using single-frequency GPS receivers provides a much more cost-effective and compact tool for these applications; however, it remains a challenge to resolve the ambiguities rapidly and reliably. To address such a technical issue, this research focuses on design of GPS measurement models that can be effectively implemented in the structural monitoring networks. The main feature of these models is that they simultaneously model all available observables within the network, including not only GPS satellite ranging signals but also some dynamic constraints of structural monitoring networks, such as nominal coordinates and baselines of the target antennas. A series of tests has been carried out, using simulated satellite geometries and measurements, to assess impact of the proposed models on kinematic positioning performance. The results indicate that overall performance of the models that employ the single-frequency GPS observables and the dynamic constraints can be significantly improved by employing the redundant measurements.