1. A magnetic screening system, comprising: an arrangement of gradiometers each including at least three magnetometers; a gradiometer processor in communication with the magnetometers that scales outputs from the magnetometers with unequal weights and combines the scaled outputs to orient a direction of sensitivity of the respective gradiometer toward a volume of interest; and at least one arrangement processor in communication with the arrangement of gradiometers that uses the gradiometers in a collective manner to detect a target object.