DOA estimation for a multi-frequency signal using widely-spaced sensors

The estimation of sub-sample time-delay from the phase of the cross-power spectrum (CPS) of signals received by widely-spaced receivers requires unwrapped phase. Conventional phase unwrapping methods require a continuous CPS that starts at zero frequency or at a frequency with a known unwrapped phase. A novel phase unwrapping method is proposed herein that is capable of carrying out the task without these requirements. The proposed method is applied to direction-of-arrival (DOA) estimation for a bandpass signal - a case that conventional methods are unable to handle. Analytical performance and experimental results confirm the effectiveness of the proposed method.