Noncoherent radar moving target indicator using fiber optic delay lines

A prime candidate for detection of low flying targets over the sea surface is high resolution radar with a noncoherent delay line canceller. Fiber optic delay lines are capable of providing the required large timebandwidth (TB) product. Optimum information capacities in the spectral region around m are estimated theoretically to correspond to timebandwidth products of and for single-mode (based on source spectral width) and graded-index multimode fibers, respectively. Pulse-to-pulse subtraction with 17-dB cancellation has been experimentally demonstrated using a 940- graded-index multimode fiber as delay line. Higher cancellation ratios are anticipated from the use of wider bandwidth fibers.