TDOA Based Direct Positioning of Co-Channel Signals Using Cyclic Cross-Spectral Functions

Passive positioning of co-channel transmitters is a major challenge in radio monitoring. Co-channel signals overlap in both the time and frequency domains but have different cyclic frequencies. A direct localization method of multiple co-channel signals is proposed in this letter based on the relative time delay information of collected signals and cyclic cross-spectral functions. It can estimate the number and cyclic frequencies of co-channel signals and separate co-channel signals through spectral slicing for direct positioning. A joint spectral function is constructed with a set of randomly generated position points, and the position estimate for each co-channel signal can be determined by searching for the maximum value of the function. Additionally, an iterative sampling method is proposed to improve the positioning accuracy with only a few additional iterations. The simulation results demonstrate the superiority of the proposed algorithm over other joint positioning algorithms in the presence of co-channel interference.