Accounting for azimuth ambiguities in interferometric performance analysis

Azimuth ambiguities affect the interferometric performance of SAR systems, causing a bias in the interferometric phase and a modulation of the interferometric coherence, as also visible in some TanDEM-X interferograms. This paper provides an explanation for this phenomenon and derives the analytical expressions for the phase bias and the coherence, resorting to the interferogram statistics for jointly circular Gaussian processes. The impact of azimuth ambiguities on the overall system performance is then considered. Plots are provided, which display the standard deviation of the phase bias, as well as the expected value and the standard deviation of the coherence loss component due to azimuth ambiguities. These plots can be useful for interferometric performance analysis.