Unknown target motion compensation for spotlight-mode synthetic aperture radar imagery

In spotlight-mode synthetic aperture radar (SAR), a long integration time is required to achieve a high cross-range resolution. Unfortunately, target motion during this long integration time will lead to undesirable smeared SAR images. The effect of subaperture integration time (SIT) on motion compensation for spotlight-mode SAR is investigated. Subaperture images are used to estimate the target velocity via object´s centroid measurements. The estimated velocity is used to achieve motion compensation. The target is assumed to have a constant translational motion. The results demonstrate how the accuracy of motion compensation depends on the SIT and target velocity. With the analysis in this paper, we can optimize the choice of the SIT