This paper presents a signal preprocessing and target tracking system based on the Multi-Frequency Continuous Wave technique, enabling the perception of targets using Commercial Off-The-Shelf high-frequency microphones and speakers. The algorithm incorporates circular fitting and subspace methods to achieve static clutter suppression, target selection, distance imaging, and gesture tracking with the aid of particle filters. Experimental results demonstrate that the integration of the subspace method and particle filters results in a reduction of the measurement distance span error by 40% compared to the traditional phase measurement approach.