Limitations on the detectability of spread-spectrum signals

The standard analysis of the radiometric detectability of a spread-spectrum signal assumes a background of stationary white Gaussian noise whose power spectral density can be measured very accurately. This assumption yields a fairly high probability of interception, even for signals of short duration. Using a generalization of the detection scenario, the authors demonstrate that realistic detection of these signals by a wideband radiometer can be considerably more difficult than is indicated by the standard result. The generalized result is then used to consider the realistic effectiveness of optimal detection of low-SNR direct-sequence pseudonoise waveforms