For the purpose of phase center estimation by taking into account the deformation of wing conformal antenna array

a new approach which performed in three stages is proposed.The first stage is carried out at range-Doppler images to estimate the primary eigen-vector associated with a given range-Doppler bin by adopting subspace tracking algorithm.Secondly

the initial estimation of phase center is obtained by fitting the unwrap phase of primary eigen-vector with least square algorithm.Finally

we calculate the deformation parameters based on these initial estimation with total least square algorithm

and the fine estimation of phase center is achieved.The most advantage of the proposed methodology is that none of the auxiliary calibration sources are needed.The effectiveness is confirmed by performance analysis and extensive simulation.