Multi-dimensional aperture design and analysis for SAR using the Cramer-Rao theorem

Abstract

We are applying the Cramer-Rao theorem to synthetic aperture radar (SAR) processing in order to establish flight paths that permit height estimation and minimize errors in reflectivity measurements. The Cramer-Rao bound (CRB) establishes a lower bound on the error variance of unbiased estimates. Error bounds are developed for multi-dimensional synthetic apertures that improve the overall performance and efficiency of monostatic, single-pass SAR missions. A computationally efficient means for the design and analysis of SAR waveforms is proposed using simulated scattering models that are limited in size. A comparison made with the error bounds for standard SAR show that estimates of scatterer range and cross-range positions are sufficiently accurate for multi-dimensional aperture SAR, even with the additional estimator for height.