Abstract:
Digital intercept receivers are currently moving away from Fourier-based analysis and towards classical time-frequency analysis techniques, such as the Wigner-Ville distribution, Choi-Williams distribution, spectrogram, for the purpose of analysing Low Probability of Intercept (LPI) radar signals. The LPI signals are difficult to detect, intercept and recognize, because they have many combined features implemented that help the LPI radar prevent its detection by modern intercept receivers. The instantaneous frequency measurement (IFM) receiver is normally a subunit used in electronic warfare receivers. Its function is to measure the frequency of pulse and continuous wave signals over a very wide bandwidth and power dynamic range. The band of interest can range from 500 MHz to 40 GHz. This is an extremely wide bandwidth. These receivers have a very high resolution (typically 1 MHz) over this very wide bandwidth and the error of these receivers is typically a few megahertz. In this work we use IFM receiver long with prony’s analyses and multiple delay lines to intercept LPI signals. We find that our scheme achieved good results in order to intercept LPI signals even when it appear simultaneously at the receiver and number of simultaneously received signals are function of number of delay lines.
