Radar separation of closely spaced targets

The capability of a hypothetical radar against attacks by closely spaced aircraft may be examined in geometric terms and the results can be plotted graphically. It is seen that a pulse Doppler type radar, which provides information about target velocity as well as range and angle, is essential in this kind of environment. When the targets are so closely spaced that all else fails, then separation or at least knowledge of the number of targets present is still possible if sufficient Doppler resolution is available to permit the measurement of the small changes in velocity that will be required for the aircraft to maintain formation.