Identification of intra pulse modulation signal in the presence of noise

In Electronic Warfare systems, Low Probability of Intercept (LPI) radar signals are used for identifying the targets in the selected region of operation. LPI radars are designed to minimize the chances of being intercepted or detected by passive radar receivers. Advanced signal processing techniques become an essential requirement when these signals are used for the detection and separation of multiple targets in a noisy environment. In this work, a noisy Stepped Frequency Modulated (SFM) waveform is detected by using high resolution spectrum estimation techniques. To improve the detection capability of the noisy SFM, two level filtering is used as pre-processing step. The filtered SFM signal is analysed using Root MUSIC and Eigenvector algorithms and the multiple target frequencies are estimated. The proposed method is successful in detecting the parameters of the SFM signal in the low Signal Noise Ratio conditions up to -9dB with an accuracy of 99%.