Abstract: A system for locating electromagnetic signal sources via the rotational Doppler effect whereby a radar station generating electromagnetic signals, such as radar frequency signals, initially scans the sky for aircraft. An aircraft having the system operationally installed thereon and utilizing apparatus or navigational systems already present on the aircraft receives radar signals. The system is programmed to capture radar signal parameters and extract the rotational Doppler frequencies induced by the motion of the aircraft. The angular velocity of the host platform is often the dominant source of this frequency; however, lateral velocity is not detrimental to the process. The measurement of the rotational Doppler frequency is accomplished through antennas presently installed on large numbers of military aircraft with no requirement for phase calibration of the electrical paths between antennas and receiver.

Abstract: A system for locating electromagnetic signal sources via the rotational Doppler effect whereby a radar station generating electromagnetic signals, such as radar frequency signals, initially scans the sky for aircraft. An aircraft having the system operationally installed thereon and utilizing apparatus or navigational systems already present on the aircraft receives radar signals. The system is programmed to capture radar signal parameters and extract the rotational Doppler frequencies induced by the motion of the aircraft. The angular velocity of the host platform is often the dominant source of this frequency; however, lateral velocity is not detrimental to the process. The measurement of the rotational Doppler frequency is accomplished through antennas presently installed on large numbers of military aircraft with no requirement for phase calibration of the electrical paths between antennas and receiver.