Manifold curve fitting in the presence of channel gain phase inconsistency and mutual coupling for uniform circular array

The manifold vector of an assembled Uniform Circular Array (UCA) usually differs from its theoretical value, and a calibration algorithm for the array manifold model is proposed on the basis of array amplitude phase response when a single signal source is incident into the UCA from different directions. Firstly, considering the existence of channel gain phase inconsistency and mutual coupling, the relationship between the amplitude phase response and the array manifold error parameters is derived. Then utilizing the feature that the mutual coupling matrix can be separated from the array manifold in the modal domain, the relational expressions about error parameters is reduced to a linear equation. Finally, the least squares estimation of the error parameters is made by combining multiple data from different directions. For the special case where there is only one kind of error, an estimation method corresponding to high accuracy and low complexity is given. Finally, the numerical method is used to evaluate the fitting accuracy of the proposed method, and the estimated array manifold error distance is reduced to the order of 10^-2. The experimental data of the pool also verify the feasibility of the algorithm in practical applications.