Comparison of backscattered signal statistics as derived from indoor scatterometric and SAR experiments

A comparison between indoor scatterometric and SAR measurements of distributed targets is presented. In particular, the backscattered signal statistics (in amplitude and phase) obtained in these two types of measurements are compared for different surface parameters (roughness and correlation length) and varying spatial resolutions in the SAR images. Experimental data have been taken in the European Microwave Signature Laboratory (EMSL) at JRC, an indoor facility which is able to measure extended targets both in scatterometric and linear SAR mode under the same conditions. The results confirm that, with spatial resolutions in the SAR image smaller than two autocorrelation lengths (ACL), the statistics of the backscattered signal depends significantly on the resolution cell size. For larger resolution cells, the experimental data are consistent with the Rayleigh model. This experimental finding substantially confirms the results based on numerical simulations, previously presented in the literature.