Self‐calibration of large phased‐array antennas for radar

Abstract

Self-calibration of a phased antenna array is required when distortions in the array are not known a priori and cannot be measured, or when turbulence in the propagation medium perturbs the radiation field. Two types of self-calibration procedures are discussed that have proved successful in experimental high-resolution two-dimensional microwave radar imaging. Each extracts information from the backscattered reradiation field to deduce a compensating weight vector for the phased array antenna. The first depends upon the presence of a strong reflector in the field of view of the transmitter.The second calibrates the array from correlation estimates of wavefront samples in the array. The basic algorithm in each group is described, along with two more sophisticated algorithms in the latter class. Two-dimensional radar images of airplanes are shown with resolution comparable to human vision. The performance of each algorithm and comparisons between them are illustrated by these images of targets and by simulation experiments. 0 1993 John Wiley 8 Sons, Inc.