Synthetic Aperture Generated by a Seaborne Target Crossing a Fixed Radar Beam - Some Theoretical Considerations

The report investigates theoretically the problem of synthetic aperture processing of the radar signature of a seaborne target crossing a fexed radar beam. Particular emphasis is placed upon accommodating the modulation from target roll. A two-dimensional target model is used to derive an ambiguity-type function relating combined resolution in height above roll axis and length along target. For sinudoidal roll the function may be calculated analytically. The number of roll periods in the coherent observation time and the roll phase are important in determining the ambiguity surface shape, particularly when the former is 1 or less. Calculated and computed examples of the surface show that it is spread out to such an extent that synthetic aperture processing does not yield a readily interpretable target image under most practical radar-target conditions. (Author)