Sufficient conditions for array calibration using sources of mixed tapes

A summary of results concerning passive array calibration using far-field sources in known/unknown directions and/or near-field sources in known/unknown locations is presented. All possible combinations of the four different types of sources are referred to. For each of them, the minimal number of sources of each kind which enable array calibration is established. Pathological geometries under which array calibration fails are presented. The justification of the results is purely geometrical so no statistical assumptions concerning the source signals and/or the sensor locations uncertainties are needed