Small target detection in sea clutter using all-dimensional Hurst exponents of complex time sequence

In this paper, nonstationary sea clutter time sequence, and corresponding amplitude sequence and phase sequence are modeled as statistically similar fractional-order Brownian motion (fBm) processes at different time scales. Their Hurst exponents form an all-dimensional description of fractal characteristics of sea clutter time sequence. Radar returns with targets and sea clutter exhibit salient differences in the all-dimensional description. Averaging three Hurst exponents followed by an adaptive threshold decision gives a simple but effective detector of sea-surface small targets. Experimental results on the recognized IPIX radar database show that the proposed detector attains much better performance than the detectors using single amplitude features and is competitive in performance with the tri-feature-based detector that requires time-consuming learning and decision processes. (C) 2020 Elsevier Inc. All rights reserved.