Interest is recently growing in exploiting the advanced multibaseline operation of synthetic aperture radar interferometry (InSAR) to solve layover effects, that can degrade conventional SAR and InSAR imagery. In this work we report about: experiments of the functionality of "layover-free" or "higher-order" interferometry with the dual-baseline single-pass SAR interferometer AER-II. Non-parametric, parametric and hybrid spatial spectral estimators are applied to process the three-antenna non uniform array data. Calibration issues, first real data results and impact of order selection are discussed for a bridge over the valley scene