Simulated analysis and optimization of a three-antenna airborne InSAR system for topographic mapping

A three-antenna synthetic aperture radar interferometer (InSAR) with a statistically optimal data processor for three-dimensional (3-D) terrain mapping has been proposed recently to reduce the phase ambiguity and data-noise drawbacks of the conventional two-antenna SAR interferometry technique. In this paper, a numerical simulator is developed to assess the achievable performance and various design tradeoffs of the three-antenna InSAR. The most critical conditions for the new reduced-ambiguity system operating on realistic scenes are taken into account. The phase-unwrapping procedure is included in the simulator to compare the new and the conventional technique in terms of both phase and height-estimation accuracy. The performance achievable by a three-antenna airborne InSAR system on a given site are analyzed, and the parameter optimization of the new system is investigated. The results of several case studies show that the new technique can outperform the conventional one significantly for a typical airborne configuration, especially for high-terrain steepness. It provides reduced-phase aliasing and better estimation accuracy. So, the phase unwrapping is simplified and high-quality maps of terrain height can be obtained. As a limit, absolute phase retrieval can be achieved with good accuracy and the unwrapping procedure can be avoided.