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

94is unacceptable with one term. The DCT and DFT techniques were performed withp = 5. In this case, the DCT's performance is similar to the SMI. The DFT is alsosimilar to the SMI with the exception of several spikes at low SNR as the pointingerror is increased. These are due to the way that the DFT processes the input signal.Additional terms in the DFT processing will reduce these effects.Figure 5.10 show the effects of the phase and pointing errors. There are noamplitude errors and the phase errors are modeled as a zero-mean Gaussian randomvariable. The phase errors were evaluated using 50 Monte Carlo runs. The SMIexhibits a larger degradation in the array gain than the eigencanceler in the caseof both pointing and phase errors. The eigencanceler exhibits almost no loss ofperformance for phase errors up to 8° while the SMI gain is decreased to 1/2 forphase errors with a standard deviation of 5°. The CSM shows good performancefor phase errors up to 6°. The DCT gain is decreased to 1/2 for phase errors witha standard deviation of 8'. The DFT's performance is similar to that of the SMI.As illustrated before, the eigencanceler's pointing error is less than that of the othertechniques.5.2 Mountain-Top DataThe performance of the various reduced-rank methods are compared to oneanother when applied to the Mountain-Top dataset . This data was collectedfrom commanding sites (mountain tops) and radar motion is emulated using atechnique developed at Lincoln Laboratories [58]. The sensor consists of 14 elementsand the data is organized in coherent pulse intervals (CPI) of 16 pulses. For thedataset analyzed here, the clutter was located around 245 degrees azimuth andthe target was at 275 degrees and at a Doppler frequency of 156 Hz. A synthetictarget was introduced in the data at 275 degrees and 156 Hz. Note that the clutterand target have the same Doppler frequency, hence separation is possible only in