Multiple reflectivities estimation for multibaseline InSAR imaging of layover extended sources

In this paper, the problem of retrieving radar reflectivity of natural layover areas is addressed. It is formulated as the problem of estimating a multicomponent sinusoidal spatial signal corrupted by multiplicative complex correlated noise - the speckle in the radar imaging jargon - and by additive white Gaussian noise. Application of nonparametric adaptive and parametric spectral estimators for amplitude estimation is investigated for a multiple looks scenario. Performance analysis is investigated through Cramer-Rao lower bound calculation and Monte Carlo simulation. The method of least squares (LS), coupled with Capon's approach for interferometric phase estimation, multilook-RELAX and multilook-APES outperform conventional beamforming and provide accurate reflectivity estimates for undistorted image formation of layover areas.