Real-time deformation monitoring by a wireless network of low-cost GPS

Monitoring small size area deformations calls for increasingly precise data with greater space and time resolution. To this aim, a GPS data processing method designed for wireless networks of mono-frequency GPS receivers is proposed. The different steps of the method are explained: the GPS processing is first detailed with the design of parametric and stochastic models, their inversion by an extended Kalman filter and the mitigation of the main errors: multipath. A parsimonious radio data transfer protocol is then proposed. It allows a real-time positioning thanks to a wireless transfer of GPS carrier phases data from receivers to a processing computer. Finally the method is tested on a network of mono-frequency receivers developed by the French National Mapping Agency (IGN). Tests prove its ability for real-time positioning with a fifteen receivers network, and a precision under the centimeter level is reached.