Phase Ambiguity Resolution for Underwater Direction Finding Based on Minimum Norm

The underwater target direction finding based on phase comparison can achieve high-precision real-time performance with fewer receivers, but faces the problem of phase ambiguity. In this regard, a minimum norm (MN) based phase ambiguity resolution method using a non-uniform linear array is proposed. The ambiguity resolution model is constructed with vectors of ambiguity number estimation residual errors. The ambiguity number corresponding to the residual error vector with the minimum norm is selected as the estimated value of the true ambiguity number. Using the phase difference observations corresponding to multiple baselines for fusion phase ambiguity resolution, the proposed method has a higher tolerance for phase difference measurement errors. Simulation results verify the effectiveness of the method.