Empirical SNR-based model of the displacement accuracy for ground-based radar measurements

Abstract

Ground-based radar interferometry offers significant capabilities for the observation of engineering structures and natural objects displacements. The quality of the recorded displacement is significantly influenced by the intensity of the reflected radar signal. In order to determine the actual accuracy of measurement performed in the field, two comparative experiments were carried out. In both cases, referential values were specified using precise instruments: a laser interferometer and a precise total station. This way, the error value equal to 0.1–0.2 mm declared by the manufacturer was confirmed in the field conditions. Furthermore, the relationship between SNR (signal-to-noise ratio) parameter and the actual measurement accuracy was analysed based on the acquired results. Due to the different ways of expressing the parameter, i.e. thermal and estimated SNR values, specific for the applied radar system, both of them were analysed. Finally, the model which allows determining the actual accuracy of displacement measurement in the field was proposed. It includes the SNR value and the distance to the object, so the accuracy can be reliably estimated upon these basic parameters without the need for additional measurement techniques.