Dim moving target detection method based on time-frequency analysis

The signal-to-clutter ratio couldn't be improved effectively for conventional spatial or temporal high-pass filter is difficult to remove clutter, especially clutter edge, and a dim moving target detection method based on the time-frequency characters difference among target, noise and clutter is presented in this paper. Theoretical analysis shows that the waveform at the target location in time-frequency domain is a small wave packet, the magnitude of the wave packet is consistent with the target amplitude, and the width of the packet is inversely proportional to target speed; the waveform at clutter edge is an "uphill" or "downhill". This target detection method takes two-stage filters to detect dim target. At first, a threshold based on false alarm ratio criteria in the time-frequency is adopted to remove noise, and then the ratio between "main lobe" and "side lobe" in the wave packet is counted to remove clutter and detect target. The dim target detection experiment under cloud is included and the result shows that the method is effective.