Abstract: A target detection method was presented based on the processing of array signal with unknown frequency. First, the received signals were processed using FFT. Then the beam-forming of every frequency unit was processed. The target was detected by calculating statistically the direction-of-arrival (DOA) results of every frequency unit, as DOA of noise frequency unit is random, and DOAs of target are nearly consistent. The simulation results shows that the detection performance of the method is consistent with the performance of processing the signal with known frequency. And the trial results prove that the algorithm is valid. A new idea is provided for the detection of weak line spectrum target.

Key words: information processing, FFT analyzing, frequency line detecting, direction-of-arrival estimation