Calibration techniques for an antenna array

A PAA communication system comprising:

• an array of antenna elements;
• at least one digital beamforming circuitry associated with at least one of said antenna elements;
• and
• a control unit configured and operable to
• generate on-line signatures responsive to signals received in one or more of said antenna elements during operation of the system,
• compare said on-line signatures with at least some portion of off-line signatures obtained responsive to signals received in one or more of said antenna elements while the system is under idealized operational conditions, at least one of said on-line and off-line signatures is generated responsive to transmission of one or more predetermined signals from at least one antenna element of said array and receipt of the transmitted signals in at least one other antenna element of said array,
• generate calibration data based on the comparison between said signatures, and
• modify parameters of one or more elements in said at least one digital beamforming circuitry based on said calibration data to compensate flaws induced in the system due to artifacts in analog or digital portions of the system.