A system (110, 210, 310) for airborne collision avoidance configured to mount on an ownship aircraft, the system comprising: a phased-array radar device (120, 220, 320) configured to transmit radar signals and receive returned radar signals; a surveillance transponder (140, 240, 340) configured to: transmit surveillance signals indicating a position and velocity of the ownship aircraft; and receive surveillance signals from another vehicle; and processing circuitry (130, 330) configured to: detect an object based on the returned radar signals; and determine a position of the other vehicle and a velocity vector of the other vehicle based on the received surveillance signals, wherein the processing circuitry (130, 330) includes common signal and data processing circuitry configured to: process data from the phased-array radar device (120, 220, 320); and process data from the surveillance transponder (140, 240, 340), wherein the processing circuitry (130, 330) is configured to determine if coordinates and speed of a detected object, as measured by the radar device, match coordinate and speed data of another vehicle as received by the surveillance transponder (140, 240, 340), and, if the processing circuitry (130, 330) determines that the detected object, as sensed by the radar device, is the same as the vehicle that has transmitted surveillance signals to the surveillance transponder, the processing circuitry is configured to determine that the object is a cooperative vehicle; wherein the processing circuitry (130, 330) is further configured to stop tracking the cooperative vehicle with the radar device, once it has been determined that said object is a cooperative vehicle but continue tracking the cooperative vehicle with the surveillance transponder, to conserve radar scan time resources for non-cooperative targets. a phased-array radar device (120, 220, 320) configured to transmit radar signals and receive returned radar signals; a surveillance transponder (140, 240, 340) configured to: transmit surveillance signals indicating a position and velocity of the ownship aircraft; and receive surveillance signals from another vehicle; and processing circuitry (130, 330) configured to: detect an object based on the returned radar signals; and determine a position of the other vehicle and a velocity vector of the other vehicle based on the received surveillance signals, wherein the processing circuitry (130, 330) includes common signal and data processing circuitry configured to: process data from the phased-array radar device (120, 220, 320); and process data from the surveillance transponder (140, 240, 340), transmit surveillance signals indicating a position and velocity of the ownship aircraft; and receive surveillance signals from another vehicle; and processing circuitry (130, 330) configured to: detect an object based on the returned radar signals; and determine a position of the other vehicle and a velocity vector of the other vehicle based on the received surveillance signals, wherein the processing circuitry (130, 330) includes common signal and data processing circuitry configured to: process data from the phased-array radar device (120, 220, 320); and process data from the surveillance transponder (140, 240, 340), detect an object based on the returned radar signals; and determine a position of the other vehicle and a velocity vector of the other vehicle based on the received surveillance signals, wherein the processing circuitry (130, 330) includes common signal and data processing circuitry configured to: process data from the phased-array radar device (120, 220, 320); and process data from the surveillance transponder (140, 240, 340), process data from the phased-array radar device (120, 220, 320); and process data from the surveillance transponder (140, 240, 340), wherein the processing circuitry (130, 330) is configured to determine if coordinates and speed of a detected object, as measured by the radar device, match coordinate and speed data of another vehicle as received by the surveillance transponder (140, 240, 340), and, if the processing circuitry (130, 330) determines that the detected object, as sensed by the radar device, is the same as the vehicle that has transmitted surveillance signals to the surveillance transponder, the processing circuitry is configured to determine that the object is a cooperative vehicle; wherein the processing circuitry (130, 330) is further configured to stop tracking the cooperative vehicle with the radar device, once it has been determined that said object is a cooperative vehicle but continue tracking the cooperative vehicle with the surveillance transponder, to conserve radar scan time resources for non-cooperative targets.