A Novel Range-Spread Target Detection Approach for Frequency Stepped Chirp Radar
This paper presents a novel range-spread target detection algorithm for frequency stepped chirp radar (FSCR) which transmits a chirp-pulse train with frequency stepped carriers. FSCR achieves high range resolution by synthetic wide-band technique, and its process includes intra-pulse matched filtering and pulse-to-pulse inverse discrete Fourier transform (IDFT) or wavelet transform. For FSCR, the high resolution range profile (HRRP) of a target is obtained by target extraction from overlapping HRRPs which is caused by oversampling. During the target extraction (sometimes called de-correlation), some strong scattering points of target echo are discarded, as the result, the signal-to-clutter ratio (SCR) might be reduced and the target detection capability is degraded. To solve this problem for FSCR, a novel detection algorithm without target extraction is addressed. The new algorithm based on the power spectrum of radar echo uses not only the amplitude information, but also the phase information of overlapping HRRPs of a target to improve the SCR, therefore, has significant performance. Moreover, the test statistic and the false alarm probability of the detector are derived, and the implementation procedure and the flow chart of the detection algorithm are designed. Finally, the detection performance is assessed by Monte-Carlo simulation, and the results indicate that the proposed algorithm has about 3 dB detection improvement in SCR compared with the spatial scattering density generalized likelihood ratio test (SSD-GRLT) detector, and at the same condition, is superior to the integrator detector. In addition, the proposed algorithm is robust and easy to implement.