PRECISION TRACKING ALGORITHMS FOR ISAR IMAGING

The simultaneous imaging and tracking of a moving target is one of the most difficult problems in inverse synthetic aperture radar (ISAR) si gnal processing. The problem is addressed here using a two-antenna ima ging radar. The target range shift is sensed with an exponentially ave raged envelope correlation algorithm, while the angle change is measur ed with a differential phase shift algorithm The three state Kalman fi lters are used in range and azimuth dimensions to provide both a filte red estimate and a one-sample-ahead prediction for the purpose of targ et tracking. The filtered range shift provides an accurate information for range bin alignment, and the target angle change provides the ang ular positions of the synthetic array elements. Therefore, the ISAR im aging simply becomes processing of a circular-are aperture. The algori thms are verified both by computer simulations and also with experimen tal data processing.