Robust detection of coherent radar signals in nearly Gaussian noise

A robust test for detection of coherent radar signals of unknown amplitude, frequency, and phase in contaminated Gaussian noise of unknown scale is proposed. The test preserves the structure of the quadrature-matched filter which is the uniformly most powerful test for purely Gaussian noise. In the new test, the sample-mean estimators are replaced by robust alpha-trimmed estimators, with an adaptive threshold derived from noise-reference samples. It is asymptotically constant false alarm rate and maximun optimal-robust for various signal amplitude models and for arbitrary signal level. Monte Carlo results demonstrate that the asymptotic analysis is also valid for small samples sizes.