Performance Improvement of Self-Holography Based Aperture Array Station Calibration

The Mid-Frequency Aperture Array (MFAA) of the Square Kilometre Array will consist of around 250 stations (subarrays). Each of these stations will have between 10
³
and 10
⁴
receive paths. Calibration of the complex valued receive path gains is usually done based on the full array correlation matrix which, at this scale, can be extremely computationally expensive. To solve this problem a self-holography method is suggested in which the complex gains are calculated by correlating the receive paths with a reference signal obtained from the same station. Initial simulation results proved its feasibility, but it was concluded that their is an avenue for improvement in the rate of convergence and the bias level of the estimated gains. This paper explores two methods to remove/ reduce the bias and to improve convergence. Simulations of these two methods are performed and the results are discussed.