Space/time/frequency methods in adaptive radar - New Jersey ...

92Figure 5.7 Probability of detection for reduced-rank methodsThe average probability of detection is then expressedIn the simulations, we found the threshold yT (p) such that P1 (p) = 10 andaveraged the thresholds over 200 runs to obtain an average threshold value. Thisvalue was then used to compute Pd (p) as a function of the SNR. For each SNR andeach method, 200 values of Pd (p) are averaged to serve as a point on the curves inFigure 5.7. The figure illustrates the same trends as Figure 5.5(a); best detectionperformance is provided by the eigencanceler and CSM, followed by DCT and DFT(indistinguishable), and finally the full-rank SMI.The effect of the CNR on performance is illustrated in Figure 5.8. The CSNR isplotted as a function of the input CNR. The CSNR is computed for a rank-reducingtransformation with r 4. As the CNR increases, the interference power spillsover more than 3-4 principal values. Thus the rank reducing transformations areinadequate in capturing the interference power and performance is degraded.