| 摘要 |
For moving target indication, in a three-pulse system, the radar returns to a rotating antenna 64 are detected (74), range sampled (76) and converted (80) to digital words in both in-phase (I) 70 and quadrature (Q) filters 110. The digital words following first and second pulses are stored in stores 82, 84 and fed with the words following the third pulse to three velocity filters 26, 28, 30 with different patterns of weighting coefficients for A, B and C channels corresponding to the three pulses. Filter 26 producing a signal F1 corresponds to a conventional MTI filter. The other filters for F2 and F3 have orthogonal weights so that noise is uncorrelated. The I and QF1signals are squared (112) and summed (114) with conversion to logarithms to provide an output F1 signal fed to video output circuits 116, the F2 and F3 signals being similarly treated. F1 also updates a leaky bucket clutter map store 32 whose contents are subtracted above zero, 20 dB and 40 dB thresholds respectively from the F1, F2 and F3 signals before these are combined and converted back to a video output for a PPI display 54. <IMAGE> |
