CIF: Small: Theory, Methods and Algorithms for Synthetic Aperture Interferometry Using Ultra-Narrowband Waveforms

Rensselaer Polytechnic Institute, Troy NY

Investigators

Abstract

Synthetic Aperture Radar (SAR) Interferometry is a unique sensor that can provide all-weather, day-and-night, high resolution information about Earth's dynamic processes on a global scale. This sensor is now an integral part of many disciplines with a wide range of applications including environmental remote sensing, geosciences and climate research, earthquake and volcanic research, 3D and 4D mapping of Earth's topography, ocean surface current monitoring, hazard and disaster monitoring, as well as defense and security related tasks. The trend in user requirements show an increasing demand for information content with the ultimate goal of global monitoring of Earth's surface and dynamic phenomena continuously. Ever-increasing demand on information requires higher bandwidth transmission, higher transmit power and consequently more complex and larger system design. This project develops a fundamentally new theory and subsequent methods and algorithms for synthetic aperture interferometry using ultra-narrowband continuous waveforms (UNB-CW). Unlike pulsed systems, UNB-CW systems are low-power, low-cost, robust, environmentally friendly, lightweight and suitable for low-payload platforms, such as micro-satellites. Central to our approach is an alternative imaging paradigm, which we refer to as Doppler-SAR imaging. Conventional SAR relies on wideband waveforms to image scatterers that lie on high resolution range contours. Doppler-SAR takes advantage of high Doppler resolution and images scatterers that lie on Doppler contours. The objective of this project is to establish the basic interferometric observable equations in the Doppler-SAR paradigm. The investigators study the interferometric phase relationships; the sensitivity to underlying parameters and topography; corresponding appropriate coherence relations; and study the effect of noise, clutter and ambiguities for the Doppler-SAR across-track interferometry.