Disclosed is a cooperative element location system especially useful for locating a cellular telephone making a call from an unknown location. The call may be a request for emergency assistance, or for location-based commercial services, for example. Various embodiments may optionally include a mobile location component, a cellular telephone enabled to chirp-on-demand, and/or an interferometer link. A mobile location component may include a directional antenna. The directional antenna may be mounted on an antenna boom on top of an emergency vehicle, for example. The mobile location component may alternately or additionally comprise a hand-held unit. System elements may cooperate to generate a situation awareness map or other display. The mobile location component may be moved in the general direction of a first location calculation associated with a first circular error of probability. After being moved in the general direction, the mobile location component may cooperate with other elements to determine a second location calculation associated with a second circular error of probability. Second and subsequent location calculations are of increasing precision, enabling an emergency vehicle or attendant to zero in on a cellular telephone.