A CLEAN-Based Synthetic Aperture Passive Localization Algorithm for Multiple Signal Sources

In passive localization, the received signal may come from multiple signal sources with different modulations. The modulations are usually resolved by high-order spectrum (HOS) processing. However, the processing causes multiple intersignal cross terms, resulting in a degradation of localization performance. To resolve the problem, this article proposes a CLEAN-based synthetic aperture passive positioning algorithm for multiple signal sources. The main idea is to locate the same modulated signal by focusing and then filtering out the located signal. Signals with the same modulation are located through the synthetic aperture passive localization method. Then, the located signals are removed and the remaining signals are recovered through inverse focusing. The multiple signals are focused, extracted, and separated according to the modulation. The effect of cross terms and multiplicative noise in the HOS is dramatically reduced. The simulation experiments show that the proposed algorithm can effectively improve localization accuracy.