Patent ID: 7511656
Filing Date: 2009-03-31
Classification: G01S

Abstract:
1. A spotlight synthetic aperture radar (SAR) system comprising: a receiver to generate input samples with respect to a map center from radar returns by sampling along a flight path; a down-range resample filter to interpolate the input samples in polar-grid coordinates to generate down-range interpolated samples on grid lines parallel to the flight path; and a cross-range resample filter to further interpolate the down-range interpolated samples to generate fully-interpolated samples on grid lines perpendicular to the flight path, wherein the down-range resample filter and the cross-range resample filter are implemented within a single field-programmable gate array (FPGA), wherein the down-range resample filter comprises: a plurality of tables to store data representing a sinc function; circuitry to select coefficients for half of the sinc function on a sample-by-sample basis from the tables for application to the input samples; weighting circuitry to apply the selected coefficients to the down-range interpolated samples provided by the down-range resample filter; a multiplexer to multiplex weighted samples provided by the weighting circuitry; and one or more accumulators to store and combine outputs from the multiplexer to generate output data comprising the fully-interpolated samples.