Effects of signal and noise spectral slopes on time delay estimates in passive localization

In passive localization, target bearing and range are determined by signal arrival-time differences at two pairs of locations. Signal and noise spectral slopes influence time delay estimates (TDE´s), which, in turn, affect the bearing and range accuracy. The variance of the estimate is greater if the signal spectrum falls off faster than the noise spectrum. Analysis shows that the variance is inversely proportional to time-bandwidth product, signal-to-noise ratio (SNR) squared, and band center frequency squared for flat signal and noise spectra. The effects of mismatch of signal and noise spectral slopes on standard deviation of TDE´s are discussed.