Improved target detection with ultra wideband radars using efficient coded waveforms

摘要

Performance evaluation of ultra wideband (UWB) radar in terms of target detection, resolution, recognition, and clutter and interference rejection depends on the structure of the radar waveform. The chirp waveform, which is commonly used in radar applications, has high time sidelobes in the level of -20 dB. Another limitation is the excessive range-Doppler cross coupling, which occurs, when the Doppler shifted signal is correlated with the original signal, and this gives a different time of arrival. In this paper, a wideband chirp-Gaussian waveform with phase coding is proposed to overcome these drawbacks. A mathematical formulation for the proposed waveform is introduced. Plots of the power spectral density, delay-Doppler Ambiguity Function (AF), and autocorrelation function are presented. These plots reveal that the chirp-Gaussian waveform reduces the sidelobe level to - 55 dB, and its AF has the property of low-level sidelobes resembling the "thumbtack" AF, the ideal ambiguity function for high resolution radar.