Use of Stepped Carrier Frequency in Fast Scan Mode to Detect Small Targets on the Sea Surface

To detect a small target on the sea surface, we propose a detection algorithm that operates in three steps: 1) representation of a 3-D complex cube in the (radial range, pulse time, and scan time) domain by using stepped carrier frequency in fast scan mode; 2) intrascan integration to transform complex cube from the pulse time domain to the radial velocity domain by using Fourier transform; and 3) interscan integration to detect a small target by using a conventional optimal coherent detector with a Fourier relationship between stepped carrier frequency and initial radial range, and a discriminator between a true target and false targets. The proposed method improves the ability to detect a small target and reduces the sensitivity to sea clutter despite relatively low radial range resolution. In experiments, our proposed method could perform accurate and robust detection of a small target.