Analysis of false alarm in heterodyne coherence accumulation based on sequence shifting and the genetic algorithm

As a new method, coherent accumulation based on sequence shifting and the genetic algorithm (GA) has been proposed to detect a weak heterodyne signal. The excellent performance of the new method was proved by an experiment in previous studies. In this paper, the phenomenon of false alarm caused by the method is revealed through numerical simulation. It is found that, when only noise exists or signal-to-noise ratio (SNR) is low, the false alarm will occur with a high probability. Based on the statistical property of the false alarm, a solution approach using multiple GA modules is proposed to avoid the false alarm. According to the approach, only when all search results of the modules are the same, can one determine that there is an actual heterodyne signal in the detection; otherwise, the inputs of the modules will be judged as noise. Thus, the false alarm can be eliminated completely even if the SNR is quite low. The studies of this paper promote the practical application of the new coherent accumulation method.