A system for determining the spatial position and orientation of each of a plurality of bodies. Each one of the bodies has at least three markers in a predetermined, relative geometric relationship. The markers are adapted to emit energy in response to an activation signal and/or to reflect energy impinging upon such passive marker from an activatable energy source. A common energy detector is provided for detecting the energy emitted by the active marker and the energy reflected by the passive marker. A common processor is provided. The processor has a memory. The memory has stored therein the predetermined, relative geometric relation of the markers for each one of the bodies. The processor compares the stored predetermined geometric relation of the markers for each of the bodies with the energy detected by the energy detector to identify the bodies emitting/or reflecting the detected energy. With such an arrangement, a body can be tracked using a very simple sequence of operation in real-time with robust positive marker identification by taking advantage of a simple marker placement methodology. Multiple bodies can scan thereby be tracked simultaneously.