Target identification from radar signatures

Modern high resolution radar techniques and real time digital signal processing advances indicate the feasibility of extracting characteristic features of aircraft targets from their radar signatures. Two basic approaches have been suggested. The low frequency approach utilizes harmonically related radar frequencies with wavelengths comparable to the target dimensions. The microwave approach utilizes spread spectrum techniques to achieve high range resolution. Synthetic aperture processing can produce two dimensional images. Pattern recognition considerations include the development of training set data and selection of an optimum feature space. The development of a passive radar target identification system has application to military surveillance radars and civilian air traffic control systems.