Computer simulation of synthetic aperture sonar or radar for classroom demonstration: Part II

Abstract

In our presentation, a Mathematica® simulation of Synthetic Aperture Acoustic Radar will demonstrate how point-like targets placed on a smooth surface can be imaged from a collection of acoustic echoes. The transmitter and receiver are collocated and modeled as a single element that stops along a linear track at collection points and hops to the next location (stop and hop approximation). The transmitter on the hypothetical apparatus will transmit a linear frequency modulated LFM chirp pulse that reflect off the targets and are recorded as echoes by the receiver at discrete locations along the track. A matched filter correlation process will perform a pulse compression of the LFM chirp. A series of still frames from the animated simulation will be displayed. These frames show the echoes arriving at different times from the targets in conjunction with a receiver wave recorder screen. The time correlation backprojection algorithm is motivated when pulse compressed arrivals are displayed (at various track locations) including the echo arrival of a hypothetical point target adjusted in the x,y plane on or near one of the actual point targets. [See Yegulap, “Fast backprojection algorithm for SAR,“ in Proc. 1999 IEEE Radar Conf., Waltham, MA, April 20–22, 1999, 60–65].