High precision displacement measurements in presence of multiple scatterers using a photonics-based dual-band radar

In this work, a dual-band photonics-based radar system is described for precise displacement measures in a multi-target scenario. The radar has been designed for application of monitoring and prevention of possible structural failures of buildings and landslides. The radar system exploits the Stepped Frequency Continuous Wave (SFCW) signal modulation and differential phase measurements are carried out on each range bin to evaluate target displacements. The system effectiveness has been already demonstrated in presence of a single target. Here we present a numerical and experimental evaluation of the displacement estimation accuracy in the case of a multi-target scenario. Our study is focused to understand how the presence of multiple targets impacts on their displacement estimates. Simulation results show a typical accuracy of less than 0.2 mm for distances up to 400 m. These results are confirmed by preliminary experimental outcomes, which take into account different operative conditions in a first measure campaign with multiple targets. Finally, concluding remarks and perspectives draw the agenda for our future investigations.