An Adaptive Spectrogram and Accelerogram Algorithm for Electronic Warfare Applications

This paper presents a novel adaptive approach to spectrogram and accelerogram calculation based on the signal chirp rate (CR). Such a method may be useful in electronic intelligence (ELINT), electronic warfare (EW) and electronic reconnaissance (ER) or in passive bistatic radar (PBR) systems where waveform parameters are unknown. Precise signal parameter estimation is important to correctly reconstruct and use the received signal for different purposes. However, due to the non-stationary nature of the analyzed waveforms, time-frequency (TF) analysis is often employed. Thanks to numerous types of TF representation techniques, various advantages can be reached. In addition, adaptive approaches allow greater accuracy and resolution to be achieved, which is essential in signal parameter estimation. In this paper, an adaptive spectrogram and accelerogram are presented for which the calculation of the CR estimation in the TF domain was used. An analysis window was changed individually with respect to the obtained instantaneous CR, which ensured optimal resolution over the TF plane. The proposed approach was tested and verified using real-life signals coming from the Air Traffic Control (ATC) radar.